Equipment for processing wafers and methods for controlling such equipment

Abstract

An apparatus for processing a wafer includes: a rotatable chuck for receiving a wafer; a heating assembly including an array of light-emitting heating components configured to heat the wafer received by the rotatable chuck by irradiating the wafer; and one or more light sensors configured to detect light emitted by the array of light-emitting heating components.

Description

Technical Field

[0001] This invention relates to a wafer processing apparatus and a method for controlling the apparatus. Background Technology

[0002] Semiconductor wafers can undergo various surface treatment processes, such as etching, cleaning, polishing, and material deposition. To perform these processes, the wafer can be mounted on a rotating chuck so that various processes can be performed on the wafer's surface.

[0003] For example, the surface of a wafer can be cleaned by applying a cleaning solution (e.g., isopropanol or deionized water) to the wafer surface. The wafer surface can then be dried by rotating the wafer using a chuck and heating it to cause the cleaning solution to evaporate. This cleaning process is commonly referred to as a rotary cleaning process.

[0004] An example of a device that can be used to clean the surface of a wafer is described in US 2017 / 0345681A1, the contents of which are also incorporated herein by reference.

[0005] The apparatus described in US2017 / 0345681 A1 includes a rotatable chuck and a liquid dispenser on which a wafer can be mounted, and the liquid dispenser is used to dispense liquid onto the upper surface of the wafer when the wafer is mounted on the rotatable chuck. The apparatus also includes an array of heating components arranged below and configured to heat the wafer when it is mounted in the rotatable chuck. After liquid is dispensed onto the surface of the wafer, the array of heating components is controlled to heat the wafer, causing the liquid to evaporate. Summary of the Invention

[0006] In its most general sense, the present invention provides a wafer processing apparatus comprising: a light-emitting heating assembly configured to heat a wafer mounted in the apparatus; and one or more light sensors configured to detect light emitted by the light-emitting heating assembly. Therefore, the apparatus of the present invention is capable of measuring the light emitted by the light-emitting heating assembly.

[0007] Measuring the light emitted by the light-emitting heating component can be useful for several different reasons. For example, the measurement can be used to identify degradation, errors, or failures in one or more of the light-emitting heating components, or to achieve more accurate control over the intensity distribution of the light emitted by the component. This can improve reproducibility between different semiconductor wafers heated by the device, or between different individual devices.

[0008] In particular, the inventors have discovered that the light emitted by the light-emitting heating component may vary over time, for example, due to the failure or degradation of one or more of the light-emitting heating components. This can lead to variations in heating conditions between different processing steps and from wafer to wafer. This can cause problems, for example, because the processes performed on semiconductor wafers may be highly sensitive to processing conditions (e.g., temperature).

[0009] The device of the present invention can be used to solve this problem because any change in the light emitted by the light-emitting component (e.g., a change in intensity) can be detected by the one or more light sensors.

[0010] The present invention can also improve the reproducibility of device-to-device wafer heating by measuring and comparing the light emitted by light-emitting heating components in different devices.

[0011] The device of the present invention can also facilitate equipment maintenance and troubleshooting. For example, the one or more light sensors can be used to detect changes in light emitted by one or more of the light-emitting components over time, which may be caused by degradation of one or more of the light-emitting components. The one or more light sensors can be used to determine which component or group of components is causing the change in emitted light, so that the faulty component can be replaced or repaired.

[0012] In some cases, the amount of power supplied to the light-emitting heating component can be adjusted based on the output from one or more sensors to compensate for changes in illumination of the light-emitting heating component.

[0013] Conventional techniques for monitoring arrays of heating components involve using a test wafer with an array of temperature sensors configured thereon. The test wafer can be mounted on the array of heating components, and the array of temperature sensors can be used to monitor the temperature at different points on the test wafer. Algorithms can then be used to adjust the power supplied to the heating components until the desired temperature is reached throughout the test wafer.

[0014] One advantage of the device of the present invention over the use of such a test chip is that the one or more light sensors can detect the light emitted by the array of light-emitting heating components in situ. In contrast, the test chip can only indirectly measure the output of the heating component by measuring the temperature of the test chip, which may also be affected by various other variables and environmental factors. Therefore, the present invention can provide more accurate and faster monitoring and control of the output of the array of light-emitting heating components.

[0015] Therefore, according to a first aspect of the present invention, a wafer processing apparatus is provided, the apparatus comprising: a rotatable chuck for receiving a wafer; a heating assembly comprising an array of light-emitting heating elements configured to irradiate the wafer received by the rotatable chuck to heat the wafer; and one or more light sensors configured to detect light emitted by the array of light-emitting heating elements.

[0016] As described above, the one or more photosensors are capable of detecting light emitted by the array of light-emitting components in situ. This facilitates the maintenance and troubleshooting of the device and / or provides improved control over the heating conditions of the wafer.

[0017] The device according to a first aspect of the invention may have any of the following optional features or (where compatible) any combination thereof.

[0018] The term “rotatable chuck” (or rotating chuck) may refer only to a wafer carrier, which is designed to hold the wafer and rotate it.

[0019] The rotatable chuck can be configured to rotate the wafer relative to a rotation axis of the rotatable chuck, the rotation axis being substantially perpendicular to a surface of the wafer.

[0020] When viewed from above, the rotatable chuck is essentially circular.

[0021] The rotatable chuck may include mechanisms (such as clamps, screws, vacuum holders, etc.) for receiving the wafer and holding it securely in place relative to the chuck.

[0022] This rotatable chuck can be used to receive wafers of a predetermined size, such as wafers with a diameter of 300 mm or 450 mm.

[0023] The rotatable chuck may include a motor for driving the rotation of the chuck relative to the rotation axis.

[0024] Alternatively, the rotatable chuck can be rotated by an external drive (e.g., via magnetic induction).

[0025] The heating assembly is used to heat a wafer mounted on the rotatable chuck. The heating assembly includes an array of light-emitting heating elements configured to illuminate the wafer received by the rotatable chuck.

[0026] Therefore, the light-emitting heating component heats the chip by using the radiation of light.

[0027] The term “array” may simply refer to multiple light-emitting and heating components, and does not necessarily mean that the light-emitting and heating components are arranged in any particular order.

[0028] When the wafer is received by the rotatable chuck, the array of light-emitting heating components can be configured to face the wafer.

[0029] The array of the light-emitting heating components can be configured to face a first surface of the wafer, which is opposite to a second surface of the wafer, on which processes (such as cleaning, material deposition, etc.) are performed.

[0030] The light-emitting heating component can be configured on a substantially flat surface (e.g., on a plate, such as a circuit board).

[0031] When the wafer is received by the rotatable chuck, the plate can be configured to be substantially parallel to the wafer.

[0032] The light-emitting heating component can be substantially uniformly distributed on the flat surface to irradiate the wafer in a uniform manner, which can cause uniform heating of the wafer.

[0033] When viewed from above, the heating element can have a circular shape.

[0034] The array of the light-emitting heating components can be configured to cover an area that is substantially the same as the area of ​​the wafer, or within 10% of the area of ​​the wafer.

[0035] All of these light-emitting heating components can be of the same type (e.g., they can all have the same characteristics).

[0036] Generally speaking, a light-emitting heating component is a component (or part) that uses light to perform radiative heating.

[0037] The light emitted by this light-emitting heating component can be visible light.

[0038] The heating element can be mounted relative to the rotatable chuck so that it does not rotate with the rotatable chuck as the rotatable chuck rotates about the axis of rotation. In other words, the array of light-emitting heating elements remains stationary as the rotatable chuck rotates about the axis of rotation. This facilitates the provision of electrical connection to the array of light-emitting heating elements.

[0039] Here, the light-emitting heating component can refer to a light source that emits light with a wavelength suitable for heating the wafer. For example, the light-emitting heating component can emit light with the maximum intensity in the wavelength range from 380 nm to 650 nm.

[0040] In some implementations, one or more of the light-emitting heating components may be light-emitting diodes (LEDs).

[0041] The light-emitting heating component can be arranged in a concentric circle manner (concentric with the center of the heating component).

[0042] Within each concentric circle, the heating element can be divided into different groups. In other words, the heating element within each concentric circle can be distributed non-uniformly around that concentric circle.

[0043] Each of these different groups may contain the same number of heating components, for example, 16 heating components.

[0044] The one or more light sensors are configured to detect light emitted by the array of the light-emitting heating components.

[0045] The one or more light sensors can therefore output a signal relating to the amount (or intensity) of light emitted by the array of the light-emitting heating components.

[0046] In this way, the amount of light emitted by the array of the light-emitting heating components can be compared with a predetermined value (such as a target value, a previous measurement value, or a reference value) to determine whether the array is operating at the desired level.

[0047] The one or more optical sensors can be calibrated (e.g., relative to a reference light source). This ensures reproducibility between different devices.

[0048] Here, a light sensor can be a sensor capable of detecting light and outputting a signal related to the amount of light detected. For example, a suitable light sensor can be a photodetector, such as a photodiode.

[0049] The one or more light sensors can be configured to detect light having a wavelength corresponding to the wavelength of light emitted by the array of the light-emitting heating components.

[0050] One or more light sensors may be located in a fixed position within the device relative to the array of light-emitting and heating components. This enables reproducible measurement of the amount of light emitted by the array of light-emitting and heating components.

[0051] In use, the array can be controlled by supplying power to the array of the light-emitting heating elements (e.g., via a power source connected to the array). This causes the light-emitting heating elements to emit light.

[0052] The signals (or signals) obtained from the one or more light sensors can be used to determine whether the array of the light-emitting heating components is emitting light at the desired intensity, for example by comparing the signal with a previous measurement or a reference signal or a target value.

[0053] The signal from the one or more light sensors can be used to calibrate the array of the light-emitting heating components. For example, the power supplied to the array of the light-emitting heating components can be adjusted until the signal indicates that the desired intensity has been reached. This can also compensate for the degradation of the light-emitting heating components over time.

[0054] The signal from the one or more light sensors can be monitored over time to check for deterioration of the array of light-emitting heating components or the occurrence of faults in the array.

[0055] In some implementations, individual groups of light-emitting and heating components in the array can be controlled separately. In this way, it can be determined whether each group is emitting light at the desired intensity.

[0056] Similarly, in some implementations, each individual light-emitting heating element can be controlled separately so that the amount of light emitted by each individual light-emitting heating element can be detected.

[0057] These implementations can further facilitate the maintenance of the equipment because they can identify a single luminescent heating element or a group of luminescent heating elements that are not functioning correctly.

[0058] The one or more light sensors may include light sensors (or more than one light sensor) arranged relative to the array of the light-emitting heating component.

[0059] The light sensor is positioned relative to the array of light-emitting and heating components, facing the array of light-emitting and heating components directly or at a certain angle.

[0060] In this way, the light emitted by the array of the light-emitting heating components can be directed toward one or more light sensors.

[0061] This enables direct detection of the light emitted by each of the light-emitting heating components in the array.

[0062] This improves the accuracy of detecting changes in the amount of light produced by the array of the light-emitting heating component. Therefore, it also improves the reproducibility of heating conditions across different devices.

[0063] The light sensor facing the array of the light-emitting heating component can mean that the light-receiving surface of the light sensor is directly or at a certain angle facing the array.

[0064] When the wafer is received by the rotatable chuck, the light sensor, which is positioned relative to the array of light-emitting and heating components, can be positioned on the opposite side of the wafer.

[0065] In other words, the light sensor, which is positioned relative to the array of light-emitting and heating components, can be configured on the opposite side of the wafer, relative to one side of the wafer illuminated by the array of light-emitting and heating components.

[0066] This can facilitate the integration of the light sensor into existing devices, as the structure of the rotatable chuck and the heating assembly does not need to be modified to accommodate the light sensor.

[0067] Furthermore, this configuration of the sensor relative to the array of light-emitting and heating components means that the sensor can be positioned further away from the array of light-emitting and heating components. Therefore, the light sensor can detect light emitted from a larger number of light-emitting and heating components, thus potentially requiring fewer light sensors to measure the light emitted by the entire array, or even a single light sensor may be sufficient to detect the light emitted by the entire array.

[0068] The light sensor, which is positioned relative to the array of light-emitting heating components, may be located on the rotation axis of the rotatable chuck and / or centered on the rotation axis of the rotatable chuck.

[0069] The array of light-emitting heating components can be symmetrically arranged around the rotation axis of the rotatable chuck. In this way, the light sensor disposed on or centered on the rotation axis of the rotatable chuck can also be centered relative to the array of light-emitting heating components.

[0070] This facilitates the detection of light emitted by all components in the array of the luminescent heating component.

[0071] The light sensor, which is positioned relative to the array of light-emitting and heating components, can be located at a predetermined fixed position opposite to the array of light-emitting and heating components.

[0072] In the case where there are more than one light sensor provided relative to the array of the light-emitting heating components, each of the light sensors provided relative to the array of the light-emitting heating components can be provided at a corresponding predetermined fixed position opposite to the array of the light-emitting heating components.

[0073] This ensures reproducibility between measurements of light emitted by the array of the light-emitting heating components.

[0074] The position of the light sensor is predetermined, which means that the distance between the light sensor and each of the light-emitting heating components is also predetermined.

[0075] The intensity of the light emitted by the array of the light-emitting heating components can be calculated based on the output signals from the one or more light sensors.

[0076] In some embodiments, the device may include a cover configured to prevent stray light from reaching the light sensor positioned relative to the array of the light-emitting heating components.

[0077] This prevents the light sensor, positioned relative to the array of light-emitting and heating components, from detecting stray light not emitted by the array of light-emitting and heating components.

[0078] Therefore, the measurement accuracy of the light emitted by the light-emitting heating component can be improved.

[0079] The light sensor, which is positioned relative to the array of light-emitting and heating components, can be located inside the cover or attached to the inside of the cover.

[0080] The cover thus provides a convenient location for mounting the light sensor. This avoids the need to modify the structure of the rotatable chuck or the array of light-emitting and heating components to accommodate one or more light sensors. This facilitates the integration of one or more light sensors into existing devices.

[0081] The cover can be installed on the frame of the equipment's processing chamber.

[0082] For example, the device may include a processing chamber in which the rotatable chuck and heating assembly are disposed. The processing chamber may be a chamber in which various processes, such as etching, material deposition, cleaning, etc., are performed on the wafer. The cover may be configured to prevent stray light from entering the processing chamber when it is mounted on the frame of the processing chamber. Therefore, the cover may be mounted on the frame of the processing chamber when measuring the light emitted by the array of the light-emitting heating assembly. Once the measurement is completed, the cover can be removed, for example, to install other equipment in the processing chamber.

[0083] The cover may include a set of alignment features to ensure that the photosensor, positioned relative to the array of light-emitting and heating components, is located at a predetermined position opposite the array of light-emitting and heating components. This ensures that the measurement of light emitted by the array of light-emitting and heating components is reproducible.

[0084] In some embodiments, the device may include only a single light sensor positioned relative to the array of light-emitting and heating components. This simplifies the device and / or facilitates the detection and / or measurement of light emitted by the array of light-emitting and heating components, since only the output signal from this single light sensor needs to be analyzed. In this way, the single light sensor positioned relative to the array of light-emitting and heating components can detect the light emitted by the entire array of light-emitting and heating components.

[0085] In some embodiments, the one or more light sensors may include light sensors configured to detect light from the array of the light-emitting heating assembly, the light being reflected from the wafer when the wafer is received by the rotatable chuck.

[0086] Therefore, when the wafer is received by the rotatable chuck, the light sensor configured to detect the reflected light can be placed on the same side of the wafer as the array of the light-emitting heating components.

[0087] When the wafer is received by the rotatable chuck, the light emitted by the array of light-emitting heating components can be reflected by the wafer. Then, some or all of the reflected light can be detected by the light sensor configured to detect the reflected light.

[0088] In this way, when the chip is received by the rotatable chuck, the light emitted by the array of light-emitting components can be detected and monitored.

[0089] This allows the light emitted by the array of light-emitting heating components to be monitored while the wafer is being processed. Therefore, in-situ compensation for degradation of the light-emitting heating components can be performed during wafer processing. This can be used to ensure that desired heating conditions are maintained during wafer processing.

[0090] The light sensor, configured to detect the reflected light, is positioned on the same plane as the array of the light-emitting heating components.

[0091] This prevents the photosensor from blocking the light emitted by the light-emitting heating component, while simultaneously ensuring that the photosensor is properly configured to receive the reflected light.

[0092] The light sensor configured to detect the reflected light and the array of the light-emitting heating components can be integrated into the same board of the device, such as a circuit board.

[0093] In this way, the sensor configured to detect the reflected light and the array of the light-emitting heating components can both be mounted on the same plate (or support). This simplifies the structure of the device.

[0094] For example, multiple light sensors configured to detect the reflected light can be distributed throughout the array of the light-emitting heating assembly. This ensures that the sensors can detect reflected light from the entire array of the light-emitting heating assembly.

[0095] This board can be a circuit board.

[0096] In some cases, the plate may include a heat sink, which is configured to dissipate the heat generated in the light-emitting heating assembly.

[0097] As described above, the device may include a plurality of light sensors configured to detect light from an array of light-emitting heating components, the light being reflected from the wafer when the wafer is received by the rotatable chuck.

[0098] This allows the light from more or all of the light-emitting heating components to be detected by the light sensor.

[0099] The foregoing has discussed embodiments in which the one or more photosensitive sensors comprise one or more photosensitive sensors disposed relative to the array of the light-emitting heating components, and embodiments in which the one or more photosensitive sensors comprise one or more photosensitive sensors configured to detect light from the array of the light-emitting heating components and reflected from the wafer. However, in some embodiments, the one or more photosensitive sensors may comprise two types of photosensitive sensors; that is, the one or more photosensitive sensors may comprise one or more photosensitive sensors opposite to the array of the light-emitting heating components and one or more photosensitive sensors configured to detect light from the array of the light-emitting heating components and reflected from the wafer.

[0100] In some embodiments, one or more of the light-emitting heating components may be light-emitting diodes (LEDs) configured to emit light having a predetermined wavelength or a wavelength within a predetermined wavelength range, and the one or more photosensors may be used to detect light having the predetermined wavelength or a wavelength within the predetermined wavelength range.

[0101] Using LEDs can be advantageous because they are highly efficient and generate relatively little waste heat. The LED emits light at a wavelength or wavelength range suitable for heating the chip. For example, the LED can emit light with one or more wavelengths in the range of 380 nm to 650 nm. Other wavelength ranges would also be suitable.

[0102] The one or more light sensors are sensitive to light of that wavelength emitted by the light-emitting heating element. This ensures accurate detection of light emitted by the array of light-emitting heating elements.

[0103] In some cases, one or more photosensors may be sensitive only to wavelengths within the predetermined wavelength range. In this way, stray light with wavelengths outside the predetermined wavelength range may not be detected by the photosensors, which can improve the accuracy of detecting light emitted by the array of the light-emitting heating components.

[0104] The device may include one or more optical filters configured to selectively transmit light having a predetermined wavelength or a wavelength within the predetermined wavelength range. For example, the filter may be a low-pass filter, a high-pass filter, or a band-pass filter.

[0105] The one or more optical filters can be configured such that the one or more light sensors receive only light that has passed through the one or more optical filters.

[0106] In this way, stray light with wavelengths outside the predetermined wavelength range can be prevented from being detected by the photosensor. This improves the accuracy of detecting light emitted by the array of light-emitting components.

[0107] The one or more filters may be integrated with or attached to the one or more optical sensors, or may be disposed separately on the one or more optical sensors.

[0108] The device may also include a controller configured to control the power supplied to the array of the light-emitting heating components and to receive the measurement outputs of the one or more light sensors.

[0109] The controller may be a computing device having software installed thereon for controlling the power supplied to the array of the light-emitting heating component and receiving measurement outputs from one or more light sensors.

[0110] Such a controller can facilitate monitoring of the light emitted by the light-emitting heating component, for example, by recording measurements from one or more light sensors.

[0111] Such measurements can then be used, for example, to determine whether there has been any degradation of the array of the light-emitting heating components over time.

[0112] The controller can be connected to a power source via a communication interface (e.g., USB, Ethernet, etc.) that supplies power to the array of light-emitting heating components. The controller can be configured to send commands to the power source to control the amount of power supplied to the array of light-emitting heating components. Similarly, the controller can be connected to one or more light sensors via a communication interface (e.g., USB, Ethernet, etc.) to receive the measurement outputs from those light sensors.

[0113] The controller can be configured to control the device based on the measurement output of the one or more optical sensors.

[0114] For example, the controller can be configured to control the power supplied to the array of the light-emitting heating components until the measurement output shows that the desired intensity of the light emitted by the array of the light-emitting heating components has been achieved. This can be achieved, for example, by comparing the measurement output or the information obtained from the measurement output with a reference value corresponding to the desired intensity. In this way, the controller can perform automatic correction of the array of the light-emitting heating components.

[0115] The controller can be configured to compare the measurement outputs of one or more light sensors, or the information obtained from the measurement outputs, with reference values, and based on the comparison results: determine information related to the operating state of one or more of the light-emitting heating components in the array; and / or adjust the power supplied to one or more of the light-emitting heating components in the array.

[0116] The reference value can be, for example, a target / expected value, a previous measurement from the same one or more light sensors, or an individual measurement obtained for one or more reference light-emitting heating components.

[0117] Information relating to the operational status of one or more of the light-emitting heating components may, for example, be the following identification result: the light intensity from the group or all of the light-emitting heating components is less than expected, and therefore one or more of the light-emitting heating components may not be operating as expected. Alternatively, this information may be the identification result of a specific light-emitting heating component that is not operating correctly due to, for example, deterioration or individual malfunction.

[0118] In this way, the controller can determine whether one or more of the light-emitting heating components are operating correctly, or whether they are undergoing degradation or malfunction. For example, if the measurement output or the information obtained from the measurement output conforms to the reference value, the controller can determine that the one or more light-emitting components are operating correctly. If the measurement output or the information obtained from the measurement output does not conform to (e.g., is lower than) the reference value, the controller can determine that the one or more light-emitting components are not operating correctly, for example, they have deteriorated or malfunctioned.

[0119] The controller can be configured to notify the user of the determined operating status of one or more light-emitting and heating components. In this way, the user can become aware of the deterioration or malfunction of the light-emitting and heating components, enabling the user to perform appropriate maintenance on the device.

[0120] The controller can be configured to store reference values ​​in memory corresponding to measurement outputs when a predetermined power level is supplied to one or more of the light-emitting heating components. In this manner, the controller can verify the operating status of the one or more light-emitting heating components by applying the predetermined power level to the one or more light-emitting heating components and comparing the measurement output or information obtained from the measurement output with the reference value. The controller can be configured to store reference values ​​for different groups of the one or more light-emitting heating components. In this manner, the controller can determine the operating status of the different groups of the one or more light-emitting heating components.

[0121] Based on a comparison result, the controller can adjust the power supplied to one or more of the light-emitting heating elements in the array. For example, if it is determined that the light intensity from a light-emitting heating element or a group of light-emitting heating elements is less than a reference value, the controller can increase the power supplied to the light-emitting heating element or the group of light-emitting heating elements to enhance the light intensity to the reference value. This power adjustment can be performed independently of the determination of the operating state, or it can be performed in accordance with the determination of the operating state.

[0122] In this way, the controller can compensate for the deterioration or failure of one or more light-emitting heating components. This can be used to ensure that the desired heating conditions (e.g., light intensity) are used when processing wafers, thus improving the reproducibility of processing between wafers and between devices.

[0123] The array of light-emitting heating components may consist of a group of multiple individually controllable light-emitting heating components, and the controller may be configured to individually control the power supplied to each of the multiple groups of light-emitting heating components.

[0124] In this way, each of the group of light-emitting and heating components can be individually activated by supplying power to the group via the controller. This reduces the complexity of the device regarding the individual control of each of the light-emitting and heating elements.

[0125] A group of light-emitting heating components may include one or more of the light-emitting heating components in an array of light-emitting heating components.

[0126] When the wafer is received by the rotatable chuck, each group of the light-emitting heating components can be configured to heat different areas of the wafer.

[0127] The plurality of light-emitting heating components are arranged concentrically around the rotation axis of the rotatable chuck, so that each group occupies a corresponding radial position. In this way, different radial regions of the wafer can be heated by activating different groups of light-emitting heating components.

[0128] The controller may be further configured to: receive measurement outputs from one or more light sensors, the measurement outputs representing the light intensity of one of the groups of multiple light-emitting heating components; compare the measurement outputs or information obtained from the measurement outputs with reference values ​​for the group; and based on the comparison results: determine information related to the operating state of the group of light-emitting heating components, and / or control the power supplied to the group of light-emitting heating components.

[0129] In this way, the controller can determine the operating status of a specific group of light-emitting heating components. The controller can execute this procedure for each group of light-emitting heating components to determine the operating status of each group. This facilitates troubleshooting and maintenance of the equipment, as it helps identify groups of light-emitting heating components that are not functioning correctly.

[0130] In order to obtain the measurement output representing the light intensity of one of the multiple groups of light-emitting heating components, the controller can be configured to control the power supplied to the group of light-emitting heating components so that the group of light-emitting heating components emits light (e.g., controlling only the group of light-emitting components to emit light, without controlling the other light-emitting heating components in the array).

[0131] The controller can be further configured to adjust the power supplied to the group of light-emitting components based on the determined operating state of the group of light-emitting heating components. In this way, each of the group of light-emitting heating components can be individually calibrated.

[0132] The controller can be configured to store a reference value for each of the plurality of groups of light-emitting and heating components in memory. The reference value for the group of light-emitting and heating components can be associated with a predetermined power level for that group. Therefore, in order to determine the operating state of the group of light-emitting and heating components, the controller can adjust the power level supplied to the group to that predetermined power level.

[0133] This reference value can be a previous measurement output obtained using one or more optical sensors.

[0134] The apparatus may include additional components required for performing processes on the wafer. For example, the apparatus may also include a liquid dispenser configured to dispense liquid (e.g., cleaning fluid) onto the surface of the wafer. The liquid dispenser may be configured to dispense liquid onto a surface of the wafer opposite to the surface of the wafer facing the array of light-emitting heating elements.

[0135] The liquid dispenser can be movable to dispense liquid at different locations on the surface of the wafer. Thus, during the cleaning process, liquid can be dispensed onto the surface of the wafer received in the rotatable chuck. The wafer can then be rotated with the rotatable chuck to remove the liquid from the wafer's surface. Any remaining liquid can then be evaporated by heating the wafer with the array of light-emitting heating components.

[0136] The apparatus may also include a transparent plate (e.g., made of quartz or sapphire) positioned between the array of light-emitting heating components and the wafer when the wafer is received in the rotatable chuck. Light emitted by the light-emitting heating components can pass through the transparent plate. The transparent plate serves to protect the array of light-emitting heating components from the effects of processes being performed on the surface of the wafer.

[0137] The device can be a cleaning device for cleaning the wafer. More specifically, the device can be a rotary cleaning device for rotary cleaning of the wafer.

[0138] The chip can be a semiconductor chip.

[0139] According to a second aspect of the invention, a method for controlling the device according to a first aspect of the invention is provided. The method of the second aspect of the invention may include the features discussed above with respect to the first aspect of the invention; therefore, these features will not be repeated.

[0140] The method may include: supplying power to the array of the light-emitting heating components; receiving measurement outputs from one or more light sensors; comparing the measurement outputs or information obtained from the measurement outputs with reference values; and based on the comparison results: determining information related to the operating state of the array of the light-emitting heating components, and / or controlling the power supplied to the array of the light-emitting heating components.

[0141] The method may also include adjusting the power supplied to the array of the light-emitting heating component based on the determined operating state.

[0142] The method may also include selectively supplying power to one or more of the light-emitting heating components and determining information related to the operating state of one or more of the light-emitting heating components. Attached Figure Description

[0143] Embodiments of the invention will be discussed below with reference to the accompanying drawings, in which:

[0144] Figure 1a This is a schematic cross-sectional view of the device according to the first embodiment of the present invention;

[0145] Figure 1b This is a schematic cross-sectional view of the first embodiment of the present invention, in which the wafer is mounted in the device;

[0146] Figure 2 This is a schematic cross-sectional view of the device according to the second embodiment of the present invention;

[0147] Figure 3 This is a schematic cross-sectional view of the device according to the third embodiment of the present invention;

[0148] Figure 4 These are examples of heating components that can be used in embodiments of the present invention. Detailed Implementation

[0149] According to the first embodiment of the present invention, Figure 1a and 1b A schematic cross-sectional view of a device 100 for processing wafers is shown. Figure 1a No chip was installed in the device. Figure 1b In this process, chip 101 is installed in device 100.

[0150] The apparatus 100 includes a rotatable chuck 102 for receiving wafers. The rotatable chuck 102 includes a chuck body 104 rotatably mounted on a base 106. The chuck body 104 is rotatable relative to the base 106 about a rotation axis indicated by numeral 108 in the figures. The rotation of the chuck body 104 relative to the base 106 can be driven, for example, by a motor (not shown), which itself can be controlled by a controller. The chuck body 104 includes a set of clamping pins 110 for receiving and securely holding the wafer in place. In this way, when a wafer is mounted on the rotatable chuck 102 via the clamping pins 110, the wafer can be rotated by rotating the chuck body 104 relative to the base 106. Figure 1b In the configuration shown, the clamping pin 110 applies a clamping force to hold the wafer 101 in place. However, alternatively, other suitable mechanisms can be used to hold the wafer 101 in place (e.g., clamps, screws, suction brackets, etc.).

[0151] The rotatable chuck 102 also includes a transparent plate 112, made of, for example, quartz or sapphire, and mounted on the chuck body 104. The transparent plate 112 is fixed to the chuck body 104 so that it rotates relative to the base 106 together with the chuck body 104. Figure 1b As shown, when the wafer 101 is mounted in the rotatable chuck 102, the transparent plate 112 is positioned substantially parallel to the wafer 101.

[0152] The apparatus 100 also includes a heating assembly 114. The heating assembly 114 includes an array of LEDs 116 configured to illuminate a wafer mounted in a rotatable chuck 102. The LEDs 114 serve as a light-emitting heating assembly for heating the wafer (e.g., wafer 101) received by the rotatable chuck. In this example, these LEDs are configured to emit light in a wavelength range from 380 nm to 650 nm. For example, LEDs 116 may emit light with maximum intensity in a wavelength range from 380 nm to 650 nm. The inventors have found this wavelength range suitable for heating semiconductor wafers. A transparent plate 112 is configured to be substantially penetrated by the wavelengths emitted by the LEDs 116, i.e., all or most of the light emitted by the LEDs 116 is transmitted through the transparent plate 112.

[0153] The heating assembly 114 also includes a plate 118. An array of LEDs 116 is mounted on the upper surface of the plate 118, which acts as a heat sink for the array of LEDs 116 to dissipate the heat generated by the LEDs 116. For example, the plate 118 may be made of a metal such as aluminum. A circuit board 120 containing driving circuitry (not shown) for the LEDs 116 is disposed on the lower surface of the plate 118. Interconnections between the array of LEDs 116 and the driving circuitry on the circuit board are fabricated through the plate 118. The plate 118 is mounted on a retaining post 122. The retaining post 122 is not connected to the chuck body 104 so that it does not rotate with the chuck body 104. The plate 118 is substantially parallel to the transparent plate 112.

[0154] When the chip is mounted in the rotatable chuck 102, the array of LEDs 116 is positioned to face the chip 101. For example... Figure 1b As shown, when the wafer 101 is mounted in the rotatable chuck 102, a transparent plate 112 is located between the array of LEDs 116 and the wafer 101. Therefore, the light emitted by the array of LEDs 116 can be transmitted through the transparent plate 112 and irradiate the wafer 101, heating it. When the wafer is mounted in the rotatable chuck 102, the transparent plate 112 can also protect the array of LEDs 116 from the effects of processes performed on the wafer 101.

[0155] The array of LEDs 116 is configured to illuminate a first surface 103 of wafer 101, which is opposite to a second surface 105 of wafer 101. The second surface 105 of wafer 101 is exposed so that processes (e.g., etching, material deposition, cleaning) can be performed on the second surface 105 of wafer 101. The array of LEDs 116 can be substantially symmetrically configured about a rotation axis 108 of a rotatable chuck 102. In this way, the array of LEDs 116 can illuminate the wafer substantially symmetrically about the rotation axis 108.

[0156] The device 100 also includes a light sensor 124 configured to detect light emitted by the array of LEDs 116. The light sensor 124 may be a light-emitting diode or other suitable light sensor and is sensitive to light emitted by the LEDs 116. The light sensor 124 may include an optical bandpass filter configured to selectively transmit a series of wavelengths corresponding to or including the wavelengths emitted by the LEDs 116. The light sensor 124 is positioned relative to and facing the array of LEDs 116, i.e., the light-receiving area of ​​the light sensor 124 faces the array of LEDs 116. The light sensor 124 is centered on the rotation axis 108 of the rotatable chuck 102. Therefore, it can be substantially centered relative to the array of LEDs 116. In this embodiment, only a single light sensor 124 is provided, and the light sensor 124 is configured to sense light from all the LEDs 116 in the array of LEDs 116.

[0157] The light sensor 124 is located at a fixed position opposite the array of LEDs 116. This improves the reproducibility of light detection from the LEDs 116. The distance between the light sensor 124 and the array of LEDs 116 can be set, for example, taking into account the brightness of the LEDs 116, the sensitivity of the light sensor 124, and the incident angle from the LED to the light sensor 124, to achieve good detection of light from all LEDs 116 in the array of LEDs 116.

[0158] exist Figure 1a The arrow indicated by reference numeral 126 in the figure illustrates the light emitted by the LED and incident on the light sensor 124. The light sensor 124 can directly detect the light emitted by the LED 116, so that the performance of the LED 116 array can be directly monitored.

[0159] The light sensor 124 can output a signal related to the amount of light detected (e.g., proportional to the amount of light detected). In this way, the light intensity produced by the array of LEDs 116 can be estimated based on the measurement output from the light sensor 124. In practice, due to variations in the incident angle across the entire array of LEDs 116, it may be difficult to estimate the absolute value of the light intensity of the LEDs 116. However, the light sensor 124 can allow the relative value of the light emitted by the LEDs 116 to be measured and tracked over time. For example, the output signal from the light sensor 124 can be recorded and monitored to determine whether there has been any change in the amount of light emitted by the array of LEDs over time, for example, due to degradation of the LEDs 116 or a fault in the array.

[0160] like Figure 1bAs shown, when the chip 101 is mounted in the rotatable chuck 102, the chip 101 is positioned between the light sensor 124 and the array of LEDs 116. Therefore, light from the LEDs 116 is blocked by the chip 101 from reaching the light sensor 124. Thus, in use, before mounting the chip in the rotatable chuck 102, the light emitted by the array of LEDs 116 can be measured to, for example, evaluate the performance of the LED array and / or calibrate the LED array. After this measurement, the chip 101 can be mounted in the rotatable chuck 102 for processing.

[0161] LEDs 116 can be configured as groups of multiple individually controllable LEDs 116. Power can be independently supplied to each of the multiple groups of LEDs 116, for example, via circuitry on circuitry on circuit board 120, so that each of the groups of LEDs 116 can be independently controlled (e.g., turned on or off). Each group of LEDs 116 may contain one or more LEDs 116 in the array. Each group of LEDs 116 can be configured to heat a specific area of ​​wafer 101 so that different areas of wafer 101 can be controlled to be heated. The multiple groups of LEDs 116 can be concentrically arranged about the rotation axis 108 of the rotatable chuck 102, so that each group occupies a corresponding radial position. In this way, different radial areas of wafer 101 can be heated by activating different groups of LEDs 116.

[0162] In order to use the light sensor 124 to obtain a measurement of the light emitted by the group, each of the LEDs in the group can be individually activated. In this way, it can be determined whether each of the LEDs in the group is operating correctly.

[0163] In order to detect light from a single LED 116 or a group of single LEDs 116, power can be supplied only to the single LED 116 or the group of single LEDs 116 so that the light sensor 124 detects only light from the single LED 116 or the group of single LEDs 116.

[0164] The device 100 may also include a controller (not shown) that controls the power supplied to the array of LEDs 116 and receives measurement outputs (e.g., output signals) from the light sensor 124.

[0165] The controller can be any suitable computing device with software installed thereon to perform the required functions. For example, the controller can be connected to circuit board 120 via a communication interface (e.g., USB, Ethernet, etc.) to control the amount of power supplied to the array of LEDs 116. Similarly, the controller can be connected to light sensor 124 via a communication interface to receive measurement outputs from light sensor 124. The controller may include memory in which various control parameters (e.g., power levels) for the array of LEDs 116 are stored. The controller may also store measurement data received from light sensor 124.

[0166] The controller can be configured to automatically control the power supplied to the array of LEDs 116 based on the measurement output received from the light sensor 124. For example, the controller can adjust the power supplied to the array of LEDs 116 until the measurement output shows that the LEDs 116 are producing the desired illumination (e.g., by comparing the measurement output with a reference value). In cases where the array of LEDs 116 comprises multiple groups of individually controllable LEDs 116, the controller can automatically adjust the power supplied to each of the groups of LEDs 116 to obtain the desired output for each group.

[0167] The controller can be configured to automatically determine the operating status of the LED 116 array, such as whether the LED 116 array is operating correctly. To this end, the controller can store reference values ​​for the LED 116 array in its memory. For example, as measured in a previous measurement, this reference value may correspond to the measurement output from the light sensor 124 when a predetermined power level is supplied to the LED 116 array. The controller then supplies the predetermined power level to the LED 116 array and compares the measurement output from the light sensor 124 with the reference value. If the measurement output matches the reference value, the controller determines that the LED 116 array is operating correctly. If the measurement output differs from (e.g., is lower than) the reference value, the controller determines that the LED 116 array is not operating correctly. When such a determination is made, the controller can notify the user so that the user can further investigate the problem and perform any appropriate maintenance. Similarly, the controller can store reference values ​​for each of a group of multiple LEDs 116 so that the operating status of each of the groups can be determined. The controller can be further configured to adjust the power supplied to the array of LEDs 116 based on the measured or determined operating state, for example, to compensate for degradation in the LEDs 116.

[0168] Figure 2A schematic cross-sectional view of an apparatus 200 for processing wafers is shown, which is a second embodiment of the present invention. Apparatus 200 includes all the features described with respect to apparatus 100, such as a rotatable chuck, a heating assembly, and a light sensor. Features of apparatus 200 corresponding to the features described with respect to apparatus 100 are described in conjunction with... Figure 1a and 1b The same reference numerals are indicated in the figures. Figure 2 This will not be described further.

[0169] In addition to the features described for device 100, device 200 includes a processing chamber 202. For example... Figure 2 As shown, a rotatable chuck 102, a base 106, a heating assembly 114, and a light sensor 124 are disposed within a processing chamber 202. The processing chamber 202 can be a chamber suitable for processing wafers. For example, the atmosphere within the processing chamber 202 (e.g., its pressure and composition) can be controlled to provide suitable conditions for processing the wafers. The processing chamber 202 includes a frame 204 in which the rotatable chuck 102, the base 106, and the heating assembly 114 (together with the pillar 122) are mounted. The processing chamber 202 also includes a cover 206 in which the light sensor 124 is mounted. The light sensor 124 is mounted in the cover 206 so that it faces the array of LEDs 116 and is centered on the rotation axis 108 of the rotatable chuck. The cover 206 is mounted on the frame 204 of the processing chamber 202 and serves to prevent stray light from entering the processing chamber 202 from the outside. In this way, the light detected by the light sensor 124 can be limited to the light emitted by the array of LEDs 116. This improves the accuracy of measuring the light emitted by the array of LEDs 116.

[0170] The cover 206 is configured to hold the light sensor 124 in a predetermined fixed position opposite the array of LEDs 116, so that the position of the light sensor 124 opposite the array of LEDs 116 can be accurately identified during measurement. This ensures the reproducibility of the measurement.

[0171] In some cases, the cover 206 is removably mounted on the frame 204 of the processing chamber 202. In this manner, for example, to mount a wafer in the rotatable chuck 102 for processing, the cover 206 can be removed from the frame 204. Once the wafer is mounted in the rotatable chuck 102, the cover 206 can be mounted on the frame 204 to close the processing chamber 202. The cover 206 and the frame 204 may include engaging alignment features to position the cover 206 relative to the frame 204. This ensures that the photosensor 124 is in a predetermined position when the cover 206 is mounted on the frame 204. For example, suitable alignment features may be located in corresponding protrusions and recesses or grooves. The configuration of the device 200 facilitates the integration of the photosensor 124 into existing devices. In practice, only the cover 206 of the processing chamber 202 needs to be modified to accommodate the presence of the photosensor 124.

[0172] Figure 3 A schematic cross-sectional view of an apparatus 300 for processing wafers, representing a third embodiment of the invention, is shown. The apparatus 300 includes a rotatable chuck 302 for receiving a wafer 301. The rotatable chuck 302 includes a chuck body 304 rotatably mounted on a base 306 and rotatable about a rotation axis indicated by reference numeral 308. The chuck body 304 includes a set of clamping pins 310 for receiving the wafer and securely holding it in place. Figure 3 In the example shown, wafer 301 is mounted in a rotatable chuck 302. The rotatable chuck 302 also includes a transparent plate 312, made of, for example, quartz or sapphire, and mounted on the chuck body 304. When the wafer is mounted in the rotatable chuck 302, the transparent plate 312 is positioned substantially parallel to the wafer 301. The rotatable chuck 302 and its components can operate in a similar manner to the rotatable chuck 102 of the device 100 described above, and the description of the components of the device 100 above can be applied to the corresponding components of this device 300.

[0173] The device 300 also includes a heating assembly 314. The heating assembly 314 includes an array of LEDs 316 configured to illuminate the wafer 301 when it is mounted in a rotatable chuck 302. The LEDs 316 serve as light-emitting heating components for heating the wafer 301. In this example, the LEDs are configured to emit light in a wavelength range from 380 nm to 650 nm. For example, the LEDs 316 may emit light with maximum intensity in a wavelength range from 380 nm to 650 nm. The transparent plate 312 is configured to be penetrated by the wavelengths emitted by the LEDs 316; that is, the light emitted by the LEDs 316 is transmitted through the transparent plate 312.

[0174] The heating assembly 314 also includes a plate 318. LEDs 316 are mounted on the upper surface of the plate 318. The plate 318 acts as a heat sink for the array of LEDs 316 to dissipate the heat generated by the LEDs 316. For example, the plate 318 may be made of a metal such as aluminum. A circuit board 320 containing driving circuitry (not shown) for the LEDs 316 is disposed on the lower surface of the plate 318. Interconnections between the array of LEDs 316 and the driving circuitry on the circuit board are fabricated through the plate 318. The plate 318 is mounted on a retaining post 322. The retaining post 322 is not connected to the chuck body 304 so that it does not rotate with the chuck body 304. The plate 318 is substantially parallel to the transparent plate 312.

[0175] An array of LEDs 316 is configured to illuminate a first surface 303 of a wafer 301, which is opposite to a second surface 305 of the wafer 301. The second surface 305 of the wafer 301 is exposed so that processes (e.g., etching, material deposition, cleaning) can be performed on the second surface 305 of the wafer 301. The array of LEDs 316 is substantially symmetrically arranged about a rotation axis 308 of a rotatable chuck 302. In this way, the array of LEDs 316 can illuminate the wafer substantially symmetrically about the rotation axis 308.

[0176] Heating assembly 314 can operate in a similar manner to heating assembly 114 of device 100 described above. For example, as discussed above with respect to device 100, the array of LEDs 316 can be configured as a group of individually controllable LEDs 316.

[0177] The device 300 also includes a group of light sensors 324. This group of light sensors 324 is disposed on the upper surface of the plate 318, i.e., on the same surface as the array of LEDs 316. The group of light sensors 324 is distributed throughout the array, for example, in a substantially uniform manner (e.g., at fixed intervals). The light sensors 324 may be photodiodes or several other suitable light sensors, and are sensitive to light emitted by the LEDs 316. The light sensors 324 may include optical bandpass filters configured to selectively transmit a series of wavelengths corresponding to the wavelengths emitted by the LEDs 316.

[0178] The light sensor 324 is positioned to face the same direction as the LED 316. In this way, the light sensor can detect light from the LED 316, which is reflected from the second surface 305 of the chip 301 when the chip 301 is mounted in the rotatable chuck 302. This is achieved through… Figure 3Arrow 326 is used to illustrate this, representing light emitted by LED 316, which is reflected by chip 301 and then detected by light sensor 324. Since the light sensors are distributed throughout the array of LEDs 316, it is possible to detect light emitted by all LEDs 316 using light sensor 324. Each light sensor 324 can output a measurement signal related to (e.g., proportional to) the amount of light detected by that light sensor 324. Circuit board 320 may include readout circuitry for acquiring the measurement signal from each light sensor 324. Interconnections between the light sensors 324 and circuit board 320 may be formed through board 318.

[0179] Therefore, the device 300 allows the measurement of light energy from the LED 316 and reflected from the wafer 301. This enables real-time monitoring of the LED 316's performance while the wafer is mounted in the rotatable chuck (e.g., while the wafer is being processed). This allows for real-time adjustment of the power supplied to the array of LEDs 316 to ensure that the wafer processing always maintains the desired heating conditions.

[0180] Device 300 may also include a controller (not shown) for controlling the power supplied to LED 316 and receiving measurement outputs (e.g., output signals) from light sensor 324. The controller can be any suitable computing device with software mounted thereon to perform the desired functions. For example, the controller may be connected to circuit board 320 via a communication interface (e.g., USB, Ethernet, etc.) to control the amount of power supplied to the array of LEDs 316 and receive measurement outputs from light sensor 324. The controller may include memory in which various control parameters (e.g., power levels) for the array of LEDs 316 are stored. The controller may also store measurement data received from light sensor 324.

[0181] The controller can be configured to perform functions similar to those described above for the controller of device 100. For example, the controller can be configured to automatically control the power supplied to LED 316 or a group of LED 316 based on the measurement output received from the light sensor 324. In this way, when the chip 301 is mounted in the rotatable chuck 302, the controller can automatically control the array of LED 316 based on measurements taken by the light sensor 324. The controller can also be configured to determine the operating status of the array or group of LED 316. Based on the determined operating status, the controller can be configured to notify the user of the operating status so that the user can perform appropriate maintenance procedures.

[0182] The apparatus of all the above embodiments may include additional components configured to process wafers mounted in a rotatable chuck. For example, the apparatus may include a liquid dispenser configured to dispense liquid onto the upper surface of the wafer (i.e., the surface of the wafer opposite to the surface of the wafer illuminated by the array of LEDs).

[0183] The device can be used to clean the wafer, such as a rotary cleaning device for rotary cleaning of the wafer.

[0184] The chip can be a semiconductor chip.

[0185] Exemplary structures of heating components 114, 314 in certain embodiments of the present invention are described in Figure 4 middle.

[0186] like Figure 4 As shown, LEDs 116 and 316 are arranged in a concentric ring around the center of heating components 114 and 314. The arrangement of LEDs 116 and 316 is rotationally symmetrical about the center of heating components 114 and 314.

[0187] Within a given concentric ring, LEDs 116 and 316 are divided into groups 401, for example, each group 401 contains 16 LEDs 116 and 316. In other words, LEDs 116 and 316 within the given concentric ring are not evenly distributed around the concentric ring.

[0188] As discussed above, the power of each of the groups 401 to LEDs 116 and 316 can be controlled independently.

[0189] In this example, there are 20 concentric rings of LEDs 116 and 316, but of course, in other implementations, the number of concentric rings can be different.

[0190] exist Figure 4 In the middle, the heating components 114 and 314 are divided into four quarter circles 402, which are connected together by the connecting part 403.

[0191] Each LED can have a power consumption of 10W and provide 3W of power.

[0192] Of course, heating components 114 and 314 can be with Figure 4 The description differs from that in the present invention. In particular, the arrangement of the LEDs in the heating assembly is not necessary for the present invention.

Claims

1. An apparatus for processing a wafer, the apparatus comprising: a rotatable chuck for receiving a wafer; a heating assembly comprising an array of light-emitting heating assemblies configured to irradiate a wafer received by the rotatable chuck to heat the wafer, wherein, an array of light-emitting heating elements arranged to illuminate a first surface of the wafer when the wafer is received by the rotatable chuck, wherein the first surface is on an opposite side to a second surface of the wafer, and wherein the second surface is exposed for processing when the wafer is received by the rotatable chuck; a liquid dispenser arranged to dispense liquid onto the second surface of the wafer; and one or more light sensors configured to detect light emitted by the array of light-emitting heating elements and configured to output a signal relating to the intensity of the light emitted by the array of light-emitting heating elements, wherein the one or more light sensors comprise a light sensor disposed relative to the array of light-emitting heating elements and arranged to be on an opposite side of the wafer to the array of light-emitting heating elements when the wafer is received by the rotatable chuck.

2. The apparatus of claim 1, wherein the light sensor disposed relative to the array of light-emitting heating elements is disposed on and / or centred on an axis of rotation of the rotatable chuck.

3. The apparatus of claim 2, wherein the light sensor disposed relative to the array of light-emitting heating elements is disposed in a predetermined fixed position opposite the array of light-emitting heating elements.

4. The apparatus of claim 2 or 3, wherein the apparatus comprises a cover configured to prevent stray light reaching the light sensor disposed relative to the array of light-emitting heating elements.

5. The apparatus of claim 4, wherein the light sensor disposed relative to the array of light-emitting heating elements is disposed within or attached to an interior of the cover.

6. The apparatus of claim 4, wherein the cover is mountable on a frame of a processing chamber of the apparatus.

7. The apparatus of claim 2 or 3, wherein the apparatus comprises only a single light sensor disposed relative to the array of light-emitting heating elements.

8. The apparatus of claim 1, wherein: the light-emitting heating elements are LEDs configured to emit light having a predetermined wavelength or wavelengths within a predetermined range of wavelengths; and the one or more light sensors are adapted to detect light having the predetermined wavelength or wavelengths within the predetermined range of wavelengths.

9. The apparatus of claim 8, wherein the apparatus comprises an optical filter configured to selectively pass light having the predetermined wavelength or wavelengths within the predetermined range of wavelengths.

10. The apparatus of claim 1, wherein the apparatus further comprises a controller configured to control power supplied to the array of light-emitting heating elements and to receive a measurement output of the one or more light sensors.

11. The apparatus of claim 10, wherein the controller is configured to compare a measured output of the one or more light sensors, or information derived from the measured output, to a reference value, and based on the comparison: determine information related to an operating state of one or more of the light-emitting heating assemblies in the array of light-emitting heating assemblies; and / or adjust the power supplied to one or more of the light-emitting heating assemblies in the array of light-emitting heating assemblies.

12. The apparatus of claim 10 or claim 11, wherein: the array of light-emitting heating assemblies is comprised of a plurality of individually controllable groups of light-emitting heating assemblies; and the controller is configured to individually control the power supplied to each of the plurality of individually controllable groups of light-emitting heating assemblies.

13. The apparatus of claim 12, wherein the controller is configured to: receive a measured output from the one or more light sensors, the measured output representing an intensity of light of one of the plurality of individually controllable groups of light-emitting heating assemblies; compare the measured output, or information derived from the measured output, related to the group of light-emitting heating assemblies to a reference value related to the group; and based on the comparison: determine information related to an operating state of the group of light-emitting heating assemblies; and / or control the power supplied to the group of light-emitting heating assemblies.

14. The apparatus of claim 11, wherein the reference value is a previous measured output from the one or more light sensors, or is derived from the previous measured output.

15. An apparatus for processing a wafer, the apparatus comprising: a rotatable chuck for receiving a wafer; a heating assembly comprising an array of light-emitting heating assemblies configured to irradiate a wafer received by the rotatable chuck to heat the wafer, wherein, an array of light-emitting heating assemblies arranged to illuminate a first surface of the wafer when the wafer is received by the rotatable chuck, wherein the first surface is on an opposite side to a second surface of the wafer, and wherein the second surface is exposed for processing when the wafer is received by the rotatable chuck; a liquid dispenser arranged to dispense liquid onto the second surface of the wafer; and one or more light sensors configured to detect light emitted by the array of light-emitting heating assemblies and configured to output a signal related to an intensity of the light emitted by the array of light-emitting heating assemblies, wherein the one or more light sensors comprise a light sensor configured to detect light from the array of light-emitting heating assemblies, the light being reflected from the wafer when the wafer is received by the rotatable chuck, and the light sensor configured to detect the reflected light is integrated into the same board or pedestal as the array of light-emitting heating assemblies of the apparatus.

16. The apparatus of claim 15, wherein: the light-emitting heating assemblies are LEDs configured to emit light having a predetermined wavelength or wavelengths within a predetermined range of wavelengths; and the one or more light sensors are adapted to detect light having the predetermined wavelength or wavelengths within the predetermined range of wavelengths.

17. The apparatus of claim 16, wherein the apparatus includes an optical filter configured to selectively pass light having the predetermined wavelength or wavelengths within the predetermined range of wavelengths.

18. The apparatus of claim 15, wherein the apparatus further includes a controller configured to control power supplied to the array of light-emitting heating elements and to receive measurement output from the one or more light sensors.

19. The apparatus of claim 18, wherein the controller is configured to compare measurement output from the one or more light sensors or information derived from the measurement output to a reference value and, based on the comparison: determine information about an operating state of one or more of the light-emitting heating elements in the array of light-emitting heating elements; and / or adjust the power supplied to one or more of the light-emitting heating elements in the array of light-emitting heating elements.

20. The apparatus of claim 18 or claim 19, wherein: the array of light-emitting heating elements is comprised of a plurality of individually controllable groups of light-emitting heating elements; and the controller is configured to individually control power supplied to each of the plurality of individually controllable groups of light-emitting heating elements.

21. The apparatus of claim 20, wherein the controller is configured to: receive measurement output from the one or more light sensors, the measurement output representing an intensity of illumination of one of the plurality of individually controllable groups of light-emitting heating elements; compare the measurement output or information derived from the measurement output about a group of light-emitting heating elements to a reference value about the group; and based on the comparison: determine information about an operating state of the group of light-emitting heating elements; and / or control power supplied to the group of light-emitting heating elements.

22. The apparatus of claim 19, wherein the reference value is a previous measurement output from the one or more light sensors or derived from the previous measurement output.

23. A method for controlling an apparatus according to any of the preceding claims, the method comprising: supplying power to the array of light-emitting heating elements; receiving measurement output from the one or more light sensors; comparing the measurement output or information derived from the measurement output to a reference value; and based on the comparison: determining information about an operating state of the array of light-emitting heating elements; and / or controlling power supplied to the array of light-emitting heating elements.

24. The method of claim 23, wherein the method comprises: selectively supplying power to one or more of the light-emitting heating elements; and determining information about an operating state of the one or more of the light-emitting heating elements.

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