Configurable illumination source for optical metrology and related methods

Abstract

The present disclosure relates to an illumination source for optical metrology. The source includes a matrix including 25 light emitting diodes (LEDs) arranged in 12 groups associated with 12 peak wavelength ranges. The peak wavelength range of the group is in the range of 400 to 1000 nanometers. Each group of LEDs is independently controlled, and each LED has a controllable intensity. The illumination source also includes a controller configured to selectively activate any combination of the LEDs and control the matrix based on a metrology method. The claims also include a method of illuminating a sample using the illumination source.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Serial No. 63 / 496,946, filed April 18, 2023, which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of optical metrology, and more specifically, to an illumination source comprising an array of light-emitting diodes (LEDs) arranged in different groups associated with different peak wavelength ranges. Background Technology

[0004] Optical metrology is a key field that involves using light to measure a wide range of properties of objects. This field has broad applications, from inspecting semiconductor wafers to analyzing biological samples.

[0005] Optical critical dimension (OCD) is a metrology technique used in the semiconductor industry to measure and characterize the dimensions of features on semiconductor wafers. It plays a crucial role in ensuring the quality and performance of integrated circuits.

[0006] OCD relies on the principle of optical scattering measurement, which involves analyzing light scattered from the surface of a patterned wafer to extract information about its dimensions. By measuring the intensity and phase of the scattered light, OCD can determine key dimensions such as linewidth, space, and height with high precision and accuracy.

[0007] A key advantage of OCD is its non-destructive nature, allowing for in-line measurements during the semiconductor manufacturing process without physical contact with the wafer. This enables real-time monitoring and control of critical dimensions, ensuring that manufactured equipment meets required specifications.

[0008] OCD can provide valuable information about dimensional variations on wafers and variations between different wafers within a batch. This data is crucial for process optimization, yield improvement, and quality control. By detecting and quantifying deviations from desired dimensions, OCD helps identify process variations and potential problems early on, allowing for corrective actions.

[0009] OCD is particularly valuable in advanced semiconductor manufacturing processes where feature sizes are becoming increasingly smaller, and measuring them using conventional techniques becomes more challenging. As industry continues to push the limits of miniaturization, OCD provides a critical tool for ensuring the quality and performance of nanoscale devices.

[0010] A key component in an optical metrology system is the illumination source, which provides light that interacts with the sample being measured.

[0011] QTH lamps, also known as quartz halogen tungsten lamps, are a type of incandescent lamp commonly used in a variety of applications, including photography, microscopy, and industrial lighting. These lamps are known for their high color temperature, excellent color rendering, and long lifespan.

[0012] A key feature of QTH lamps is the use of a tungsten filament encased in a quartz housing. This design allows the lamp to operate at higher temperatures, producing a higher color temperature compared to standard incandescent lamps. The quartz housing also provides better thermal stability and chemical resistance, making QTH lamps suitable for harsh environments.

[0013] QTH lamps emit a continuous spectrum, which is important in applications requiring accurate color reproduction, such as photography and microscopy. The high color rendering index (CRI) of QTH lamps ensures that colors are natural and vibrant, making them ideal for applications where color accuracy is critical.

[0014] Quartz tungsten halide (QTH) lamps provide broad-spectrum light, making them suitable for a variety of applications. However, these sources have certain limitations. These QTH lamps are broadband light sources and require follow-up bandpass filters to selectively filter out unwanted wavelengths and confine the emission to a narrow range. However, these filters have fixed filtering capabilities. Therefore, there is a need for an improved illumination source that can provide a general and customizable light output for optical metrology applications. Summary of the Invention

[0015] According to one embodiment, an illumination source for optical metrology is provided. The illumination source includes a matrix comprising at least 25 light-emitting diodes (LEDs) arranged in at least 12 different LED groups associated with at least 12 peak wavelength ranges. Each LED in any group is controlled independently of any other LED in the matrix. The illumination source also includes a controller configured to selectively activate any combination of any LEDs in the matrix and control the matrix based on a metrological method.

[0016] According to the implementation method, the matrix may include 25 or more LEDs. For example, it may include 6×6 LEDs, 7×7 LEDs, 8×8 LEDs, 6×5 LEDs, 5×7 LEDs, etc.

[0017] According to the implementation, the LEDs are arranged in a rectangular array, a square array, or any other shape.

[0018] According to the implementation method, the number of groups exceeds 12.

[0019] According to the implementation method, the matrix may include 25 or more LEDs. For example, it may include 36 LEDs, 48 ​​LEDs, etc.

[0020] According to an embodiment, a method for illuminating a sample is provided. The method involves irradiating the sample with radiation using an illumination source comprising a matrix of 25 light-emitting diodes (LEDs) arranged in 12 different LED groups associated with 12 peak wavelength ranges. Each LED in any group is managed independently of any other LEDs in the structured arrangement.

[0021] It has been found that specific combinations of the wavelength ranges of the 12 LED groups are well-suited for metrology of a wide range of samples and structures. Attached Figure Description

[0022] Figure 1 An example of the method is shown;

[0023] Figure 2 An example of a lighting source is shown; and

[0024] Figure 3 Examples of images generated using different lighting schemes are shown. Detailed Implementation

[0025] According to an embodiment, an illumination source for optical metrology is provided, the illumination source comprising a matrix including 25 light-emitting diodes (LEDs) arranged in 12 different groups of LEDs associated with 12 peak wavelength ranges, wherein (i) the peak wavelength range of the first and second groups is in the range of 400 to 500 nanometers, (ii) the peak wavelength range of the third group is in the range of 500 to 600 nanometers, (iii) the peak wavelength range of the fourth group is in the range of 600 to 700 nanometers, (iv) the peak wavelength range of the fifth, sixth and seventh groups is in the range of 700 to 800 nanometers, (v) the peak wavelength range of the eighth and ninth groups is in the range of 800 to 900 nanometers, and (vi) the peak wavelength range of the tenth, eleventh and twelfth groups is in the range of 900 to 1000 nanometers.

[0026] According to the implementation method, the peak wavelength range of the first group is in the range of 400 to 405 nanometers, the peak wavelength range of the second group is in the range of 450 to 455 nanometers, the peak wavelength range of the third group is in the range of 525 to 530 nanometers, the peak wavelength range of the fourth group is in the range of 670 to 680 nanometers, the peak wavelength range of the fifth group is in the range of 700 to 705 nanometers, and the peak wavelength range of the sixth group is in the range of 725 to 750 nanometers.

[0027] According to the implementation method, the peak wavelength range of the seventh group is 785 to 790 nanometers, the peak wavelength range of the eighth group is 825 to 830 nanometers, the peak wavelength range of the ninth group is 860 to 870 nanometers, the peak wavelength range of the tenth group is 905 to 910 nanometers, the peak wavelength range of the eleventh group is 940 to 950 nanometers, and the peak wavelength range of the twelfth group is 985 to 990 nanometers.

[0028] According to the implementation method, each of the third to eleventh groups consists of more LEDs than the first to fourth groups, and the twelfth group has the highest number of LEDs among any of the groups.

[0029] According to the implementation method, each of the first to fourth groups consists of a single LED, each of the fifth to tenth groups consists of a pair of LEDs, the eleventh group consists of three LEDs, and the twelfth group consists of six LEDs.

[0030] According to the implementation method, each LED in any group of the matrix is ​​controlled independently of any other LED in the matrix.

[0031] According to the implementation method, the group is controlled independently of any other group in the matrix.

[0032] According to the implementation method, each LED in the matrix has a controllable intensity.

[0033] According to one implementation, the lighting source includes a controller.

[0034] According to the implementation, the controller is configured to selectively activate any combination of any LEDs in the matrix.

[0035] According to an implementation, the controller is configured to select from a first plurality of red light illumination combinations, a second plurality of infrared illumination combinations, and a third plurality of blue light illumination combinations.

[0036] According to the implementation, the controller is configured to control at least one of the control groups to continuously illuminate the sample.

[0037] According to the implementation, the controller is configured to control at least one of the non-continuous lighting samples in the control group.

[0038] According to the implementation method, the controller is configured to control the matrix based on a metering method.

[0039] According to the implementation, the controller is configured to control the matrix to illuminate the sample with different combinations of LEDs during different lighting pulses.

[0040] A lighting source is provided that can replace the currently used QTH lamp with a filter wheel used in the pattern recognition and autofocus (AF) module of an integrated metering tool.

[0041] The lighting source is cost-effective. Some costs are reduced by replacing the continuously operating QTH lamps with LEDs that are off most of the time and activated during image acquisition, which is a very short period of time.

[0042] The lighting source is compact and can replace existing QTH lamp lighting modules.

[0043] Based on the advantageous use of LEDs (e.g., by increasing / amplifying wavelength / range—e.g., IR, blue, power consumption, etc.) for pattern recognition (PR), the lighting source exhibits improved performance (compared to QTH lighting modules).

[0044] Light sources can emit radiation of different colors—such as red (IR) radiation as well as other colors of radiation.

[0045] The lighting source supports patterns that match current and future challenges, allowing for maximum flexibility in the shortest time, improving reliability, having sufficient power to illuminate a single color sample, and exhibiting a large dynamic range that allows for a wide range of lighting configurations.

[0046] The lighting source can use an LED matrix that can change and / or mix emission colors, with each LED or group of LEDs being independently controlled.

[0047] At least one LED in the matrix can be a multi-color LED.

[0048] The versatility of illumination sources allows for support of multiple metrology methods, which is an advantage in addressing pattern recognition challenges. Compared to current practices where methods should be generated for each layer, illumination sources allow for the generation of methods with more baseline combinations.

[0049] During the evaluation of a sample, the lighting can be changed rapidly, thus providing a wealth of information about the sample.

[0050] Figure 1 An example of method 100 is shown.

[0051] According to one implementation, method 100 includes step 110 of configuring the lighting matrix by determining which LEDs of the matrix will operate during an evaluation iteration, when any LEDs of the matrix will operate, and at what intensity. Step 110 may be performed at LED resolution or a set of LED resolutions.

[0052] According to the implementation, step 110 is followed by step 120, which involves illuminating the sample during the evaluation iteration.

[0053] According to one implementation, step 120 involves directing radiation from a matrix comprising 25 light-emitting diodes (LEDs) onto the sample for measurement purposes. This matrix is ​​organized into twelve groups, each corresponding to a specified wavelength range. The purpose of this configuration is to provide an adjustable light source to meet the specific requirements of the metrology task.

[0054] This matrix allows for independent control of each LED, enabling adjustment of intensity and wavelength combinations. The controller is responsible for activating any combination of LEDs and can be programmed to illuminate the sample continuously or discontinuously based on predetermined parameters, or to vary the illumination during different pulses.

[0055] The matrix is ​​designed to enable independent management of each LED, allowing for fine-tuning of light output to achieve a desired illumination distribution. This feature is crucial for obtaining accurate measurements in metrology, where the precision of the characterization can depend on the specificity of the light source.

[0056] Steps 110 and 120 include the configuration and operation of a matrix designed for metrology, providing each LED with a customizable and precise illumination source capable of emitting light over a wide wavelength range with independently controllable intensity.

[0057] Step 120 involves the independent management of each LED within the structured arrangement. This step allows for adjustment of the intensity, on / off state, and illumination duration of each LED. The purpose of this capability is to customize the light output to meet specific metrology task requirements. For example, if a specific feature on a sample requires illumination with a specific wavelength and intensity, only LEDs corresponding to that wavelength range can be activated at the desired intensity level.

[0058] Method 100 involves using a matrix and a controller, along with software executed by the controller for the lighting process. The controller executes instructions specifying which LEDs should be activated, their intensity levels, and their lighting timing. This allows the lighting source to produce various combinations of wavelength ranges and intensities, which is essential for high-quality measurements where different materials and structures may require different lighting conditions.

[0059] The parameters set in step 110 include electrical characteristics related to the operation of each LED, such as voltage and current, which are adjusted to determine the intensity of the emitted light. The controller is configured to modify these parameters for each LED without affecting other LEDs. Furthermore, timing control is precise to ensure that LEDs are activated and deactivated at predetermined times, especially in cases of discontinuous lighting.

[0060] Therefore, step 120 involves the independent adjustment of each LED (or each group) in the matrix to provide specific illumination for measurement. This step is necessary to achieve the flexibility and control required for accurate measurement of a variety of samples under different conditions.

[0061] Step 110 can benefit from having one or more groups comprising more than one LED, with the number of LEDs in each group affecting the intensity and coverage of the light that can be emitted, where a higher count allows for stronger illumination capabilities within their respective wavelength ranges.

[0062] The intensity of each LED (or the intensity of each group) can be adjusted individually, allowing for precise control of the illumination pattern. This capability enables the adjustment of light output to meet the specifications of different metrology processes, which may require specific combinations of intensity and wavelength for optimal measurement accuracy.

[0063] In practice, these steps are achieved through the engineering and production of the LED matrix, the programming of controllers to manage the intensity and activation of each LED, and the integration of the illumination source into the optical metrology system. The controller's ability to selectively activate and modulate LEDs enables the system to adapt to various measurement scenarios, providing a flexible and effective tool for sample characterization.

[0064] Figure 2 This is an example of illumination source 200, which can be used as a component in optical metrology, enabling precise sample illumination with customizable wavelength ranges and intensities. LED matrix 202, part of illumination source 200, consists of 25 LEDs organized into 12 groups, each group corresponding to a specific wavelength range. This arrangement allows for independent control and intensity adjustment of each LED, facilitating customized illumination for metrological applications.

[0065] LED matrix 202 serves as the core of illumination source 200, with its 25 light-emitting diodes grouped into 12 LED groups. Each group is associated with a peak wavelength range identified by a wavelength range, enabling the selection of specific wavelengths for different metrological tasks. The ability to operate each LED independently (or at least each group independently) allows for customized illumination patterns, which is necessary for accurate measurements to achieve the desired contrast and resolution on the surface of a sample. The intensity of each LED is adjustable, providing control over the illumination conditions.

[0066] System controller 204 communicates with lighting source 200 to manage the activation and modulation of LEDs. It can activate any combination of LEDs, allowing for a range of lighting scenarios. The controller can execute continuous or pulsed lighting sequences according to the measurement strategy. It also follows predefined metrology methods to ensure the repeatability and consistency of measurements. The controller's ability to select from various lighting combinations, including red, infrared, and blue light, enables the system to adapt to different metrology challenges. By controlling the matrix according to these methods, the system can illuminate the sample under optimal lighting conditions in each measurement cycle, improving the reliability and accuracy of the metrology process.

[0067] The LED matrix 202 serves as the core of the illumination source for optical metrology. It consists of 25 light-emitting diodes arranged in 12 groups, each group corresponding to a specific peak wavelength range. The first and second groups emit in the 400 to 500 nanometer range, while subsequent groups cover a wavelength range up to 1000 nanometers, extending from the visible spectrum to the infrared.

[0068] Each LED in the matrix can be controlled independently, allowing for the selection of individual LEDs or groups of LEDs to be activated. This feature enables the customization of the illumination pattern to match the requirements of the metrology task, whether continuous or pulsed light, single wavelength or combination. The intensity of each LED is adjustable, providing a way to fine-tune the illumination power for the sample being tested.

[0069] The system controller 204 interfaces with the LED matrix to execute the metrology method. It selects appropriate combinations of LEDs and controls their operation, whether for continuous operation in steady-state measurements or pulse operation in time-resolved analysis. This adaptability is key to adjusting the metrology system to suit various samples and measurement conditions, ensuring accurate data acquisition.

[0070] The system controller 204 is a component in the optical metrology illumination source that can precisely control the LED matrix 202. It manages the individual LED groups and their wavelength ranges to achieve the specific illumination conditions required for sample analysis.

[0071] The system controller (204) is responsible for the operation of the LED matrix 202, including the ability to independently manage the intensity of each LED. This capability allows for customized illumination distribution, enabling the selection of specific wavelengths for target sample analysis. The controller can activate any combination of LEDs within the matrix, which is essential when different metrology methods are required. This feature allows for rapid switching between LED combinations without significantly impacting throughput.

[0072] According to the implementation method, some LEDs meet at least one of the following requirements:

[0073] 1. Reach full intensity within 100μs.

[0074] 2. After the shutdown operation, reduce to 10% of their full intensity. -5 .

[0075] Table 1 shows examples of the properties of 12 groups of LEDs.

[0076]

[0077] Table 1

[0078] According to the implementation method, the matrix can be operated in any one or more ways:

[0079] a. Operation of one or more groups of LEDs.

[0080] b. Operation of one or more LEDs in a group or multiple groups of LEDs.

[0081] c. Continuous operation of one or more LEDs.

[0082] d. Discontinuous operation of one or more LEDs.

[0083] e. Continuous operation of one or more groups of LEDs.

[0084] f. Discontinuous operation of one or more groups of LEDs.

[0085] Furthermore, the controller is configured to support continuous and discontinuous illumination modes, providing flexibility in the temporal domain of sample exposure. It can also execute complex illumination strategies, such as varying the LED combination during different illumination pulses, which is crucial for optimizing the quality of images captured during metrology and ensuring reliable feature detection.

[0086] The system controller 204 acts as the command center for the LED matrix 202, specifying the operating modes and intensity levels of the LEDs. This enables the lighting source 200 to provide customized lighting conditions for precise optical measurements.

[0087] According to one embodiment, the LED matrix 202 is optically coupled to an optical coupling and homogenizing optics 206, such as an adapter, which includes a homogenizer and terminates at an optical fiber coupler interface 208 that interfaces with an optical fiber or fiber bundle 210.

[0088] Examples of fiber optic bundles are fiber optic bundles 945-00760-00 or 945-01468. Both have an effective diameter of 4 mm. Other diameters are available.

[0089] The lighting configuration may change during the evaluation iteration or during the testing of the matrix.

[0090] Test sequences may include:

[0091] 1. 800ms continuous operation of IR LED.

[0092] 2. 11-second pulse operation in either the red group or the infrared group.

[0093] - Pulse duration 4-30 milliseconds.

[0094] - Continuous pulses, with at least a 10ms off time between pulses.

[0095] - There is a minimum 200ms off time between up to four such pulse groups.

[0096] -1, 2 The 8-second shut-off time between the sequence described and the next sequence.

[0097] Table 1 shows examples of different lighting configurations for 12 groups of LEDs:

[0098] Figure 3 Examples of images of samples obtained under different lighting conditions are shown, collectively referred to as 300.

[0099] The detailed description sets forth numerous specific details to provide a thorough understanding of this application. However, those skilled in the art will understand that this application can be practiced without these specific details. In other instances, well-known methods, processes, and components have not been described in detail to avoid obscuring this application.

[0100] The subject matter of this application is specifically pointed out and explicitly claimed in the concluding section of the specification. However, the organization and operation of this application, as well as its purpose, features, and advantages, can be best understood by referring to the detailed description when read in conjunction with the accompanying drawings.

[0101] It should be understood that, for the sake of simplicity and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to others for clarity. Furthermore, reference numerals may be repeated in the figures where deemed appropriate to indicate corresponding or similar elements.

[0102] Because the embodiments shown in this application can be implemented in most cases using electronic components and circuits known to those skilled in the art, the details will not be explained to a greater extent than is deemed necessary above in order to understand and appreciate the basic concepts of this application and to avoid confusing or distracting attention from the teachings of this application.

[0103] Any references to methods in the specification should be applied in the same way as to systems capable of executing those methods.

[0104] Any references to the system in the specification should be applied in the same way as methods that can be executed by the system.

[0105] Any value (such as time value, size, signal value, frequency, standard) is merely a non-limiting example.

[0106] In the foregoing specification, specific examples of embodiments of this application have been described with reference to them. However, it will be apparent that various modifications and changes may be made therein without departing from the broader spirit and scope of this application as set forth in the appended claims.

[0107] Furthermore, the terms “front,” “rear,” “top,” “bottom,” “upper,” “lower,” etc., as used in the specification and claims (if any) are for descriptive purposes and are not necessarily used to describe permanent relative positions. It should be understood that the terms thus used are interchangeable where appropriate, such that embodiments of the present application described herein can be operated, for example, in orientations other than those shown or otherwise described herein.

[0108] The connections discussed herein can be of any type suitable for transmitting signals from or to a corresponding node, unit, or device, for example, via an intermediate device. Therefore, unless otherwise implied or stated, a connection can be, for example, a direct connection or an indirect connection. Connections can be described or illustrated with reference to a single connection, multiple connections, unidirectional connections, or bidirectional connections. However, different implementations can change how a connection is implemented. For example, a separate unidirectional connection can be used instead of a bidirectional connection, and vice versa. Furthermore, multiple connections can be replaced by a single connection that transmits multiple signals serially or in a time-multiplexed manner. Similarly, a single connection carrying multiple signals can be separated into various connections carrying subsets of those signals. Therefore, there are many options for transmitting signals.

[0109] Although a specific type of conductivity or polarity of the potential has been described in the examples, it should be understood that the type of conductivity and polarity of the potential can be reversed.

[0110] Each signal described herein can be designed as either positive or negative logic. In the case of a negative logic signal, the signal is active low, where a true logic state corresponds to logic level zero. In the case of a positive logic signal, the signal is active high, where a true logic state corresponds to logic level one. Note that any signal described herein can be designed as either a negative or positive logic signal. Therefore, in alternative implementations, those signals described as positive logic signals can be implemented as negative logic signals, and those signals described as negative logic signals can be implemented as positive logic signals.

[0111] Furthermore, when it comes to presenting a signal, status bit, or similar device as its logical true or logical false state, this document uses the terms “assert” or “set” and “deny” (or “deassert” or “clear”). If a logical true state is logic level one, then a logical false state is logic level zero. If a logical true state is logic level zero, then a logical false state is logic level one.

[0112] Those skilled in the art will recognize that the boundaries between logic blocks are merely illustrative, and that alternative implementations may combine logic blocks or circuit elements, or apply alternative decompositions of functionality to various logic blocks or circuit elements. Therefore, it should be understood that the architecture described herein is merely exemplary, and many other architectures implementing the same functionality can actually be implemented.

[0113] Any arrangement of components that perform the same function is effectively “associated” to achieve the desired function. Therefore, any two components combined in this paper to achieve a specific function can be considered “associated” with each other to achieve the desired function, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered “operably connected” or “operably coupled” to each other to achieve the desired function.

[0114] Furthermore, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations can be combined into a single operation, a single operation can be distributed among additional operations, and operations can be performed with at least partial overlap in time. Moreover, alternative implementations may include multiple instances of a particular operation, and the order of operations can be varied in various other implementations.

[0115] Similarly, for example, in one implementation, the illustrated example can be implemented as circuitry located on a single integrated circuit or within the same device. Alternatively, the example can be implemented as any number of discrete integrated circuits or discrete devices interconnected with each other in a suitable manner.

[0116] However, other modifications, variations, and substitutions are also possible. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

[0117] In the claims, any reference numerals placed between parentheses should not be construed as limiting the claims. The word “comprising” does not exclude the presence of other elements or steps besides those listed in the claims. Furthermore, the terms “a” or “an” as used herein are defined as one or more. Moreover, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed as implying that the introduction of another claim element by the indefinite article “a” or “an” limits any particular claim containing such an introduced claim element to an application containing only one such element, even when the same claim includes the introductory phrase “one or more” or “at least one” and the indefinite article such as “a” or “an.” The same applies to the use of definite articles. Unless otherwise stated, terms such as “first” and “second” are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate the time or other priority of these elements. The fact that certain measures are recited in dissimilar claims does not mean that combinations of these measures cannot be advantageously used.

[0118] Although certain features of this application have been described and illustrated herein, many modifications, substitutions, alterations, and equivalents will now occur to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and alterations that fall within the true spirit and scope of this application.

Claims

1. An illumination source for optical metrology, the illumination source comprising: The matrix comprises 25 light-emitting diodes (LEDs) arranged in 12 different groups of LEDs associated with 12 peak wavelength ranges, wherein (i) the peak wavelength range of the first and second groups is in the range of 400 to 500 nanometers, (ii) the peak wavelength range of the third group is in the range of 500 to 600 nanometers, (iii) the peak wavelength range of the fourth group is in the range of 600 to 700 nanometers, (iv) the peak wavelength range of the fifth, sixth and seventh groups is in the range of 700 to 800 nanometers, (v) the peak wavelength range of the eighth and ninth groups is in the range of 800 to 900 nanometers, and (vi) the peak wavelength range of the tenth, eleventh and twelfth groups is in the range of 900 to 1000 nanometers.

2. The lighting source according to claim 1, wherein, The peak wavelength range of the first group is 400 to 405 nanometers, the peak wavelength range of the second group is 450 to 455 nanometers, the peak wavelength range of the third group is 525 to 530 nanometers, the peak wavelength range of the fourth group is 670 to 680 nanometers, the peak wavelength range of the fifth group is 700 to 705 nanometers, and the peak wavelength range of the sixth group is 725 to 750 nanometers.

3. The lighting source according to claim 1, wherein, The peak wavelength range of the seventh group is 785 to 790 nanometers, the peak wavelength range of the eighth group is 825 to 830 nanometers, the peak wavelength range of the ninth group is 860 to 870 nanometers, the peak wavelength range of the tenth group is 905 to 910 nanometers, the peak wavelength range of the eleventh group is 940 to 950 nanometers, and the peak wavelength range of the twelfth group is 985 to 990 nanometers.

4. The lighting source according to claim 1, wherein, Each of the third to eleventh groups consists of more LEDs than the first to fourth groups, and the twelfth group has the highest number of LEDs among all the groups.

5. The lighting source according to claim 1, wherein, Each of the first to fourth groups consists of a single LED, each of the fifth to tenth groups consists of a pair of LEDs, the eleventh group consists of three LEDs, and the twelfth group consists of six LEDs.

6. The lighting source according to claim 1, wherein, Each LED in any group of the groups is controlled independently of any other LED in the matrix.

7. The lighting source according to claim 1, wherein, This group is controlled independently of any other group in the matrix.

8. The lighting source according to claim 1, wherein, Each LED in the matrix has a controllable intensity.

9. The lighting source according to claim 1, wherein, It also includes the controller.

10. The lighting source according to claim 9, wherein, The controller is configured to selectively activate any combination of any LEDs in the matrix.

11. The lighting source according to claim 9, wherein, The controller is configured to select from a first plurality of red light illumination combinations, a second plurality of infrared illumination combinations, and a third plurality of blue light illumination combinations.

12. The lighting source according to claim 9, wherein, The controller is configured to control at least one of the groups to continuously illuminate the samples.

13. The lighting source according to claim 9, wherein, The controller is configured to control at least one of the groups to provide discontinuous illumination of the samples.

14. The lighting source according to claim 9, wherein, The controller is configured to control the matrix based on a metering method.

15. The lighting source according to claim 9, wherein, The controller is configured to control the matrix to illuminate the sample with different combinations of LEDs during different lighting pulses.

16. The lighting source according to claim 1, wherein, The matrix includes more than 25 LEDs.

17. A method for illuminating a sample, the method comprising: The sample was illuminated using a radiation source comprising a matrix of 25 light-emitting diodes (LEDs) arranged in 12 different groups of LEDs associated with 12 peak wavelength ranges, wherein (i) the peak wavelength range of the first and second groups is in the range of 400 to 500 nanometers, (ii) the peak wavelength range of the third group is in the range of 500 to 600 nanometers, (iii) the peak wavelength range of the fourth group is in the range of 600 to 700 nanometers, (iv) the peak wavelength range of the fifth, sixth and seventh groups is in the range of 700 to 800 nanometers, (v) the peak wavelength range of the eighth and ninth groups is in the range of 800 to 900 nanometers, and (vi) the peak wavelength range of the tenth, eleventh and twelfth groups is in the range of 900 to 1000 nanometers.

18. The method according to claim 17, wherein, The peak wavelength range of the first group is 400 to 405 nanometers, the peak wavelength range of the second group is 450 to 455 nanometers, the peak wavelength range of the third group is 525 to 530 nanometers, the peak wavelength range of the fourth group is 670 to 680 nanometers, the peak wavelength range of the fifth group is 700 to 705 nanometers, and the peak wavelength range of the sixth group is 725 to 750 nanometers.

19. The method of claim 17, wherein, The peak wavelength range of the seventh group is 785 to 790 nanometers, the peak wavelength range of the eighth group is 825 to 830 nanometers, the peak wavelength range of the ninth group is 860 to 870 nanometers, the peak wavelength range of the tenth group is 905 to 910 nanometers, the peak wavelength range of the eleventh group is 940 to 950 nanometers, and the peak wavelength range of the twelfth group is 985 to 990 nanometers.

20. The method of claim 17, wherein, Each of the third to eleventh groups consists of more LEDs than the first to fourth groups, and the twelfth group has the highest number of LEDs among all the groups.

21. The method according to claim 17, wherein, Each of the first to fourth groups consists of a single LED, each of the fifth to tenth groups consists of a pair of LEDs, the eleventh group consists of three LEDs, and the twelfth group consists of six LEDs.

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