Ultraviolet LED module dodging control system for semiconductor wafer defect detection

Abstract

The invention discloses an ultraviolet LED module dodging control system for semiconductor wafer defect detection, and relates to the technical field of semiconductor manufacturing and detection, and the system comprises an ultraviolet LED array module which generates an ultraviolet detection light source and projects the ultraviolet detection light source to the surface of a wafer; the multi-dimensional parameter sensing module is used for acquiring the physical state of the module and the parameters of the output light field in real time; the dynamic driving control module is used for performing high-precision modulation on the driving current; the central processing and dodging algorithm module is used for receiving the sensing data and generating an adjusting instruction based on a built-in algorithm strategy; and the active thermal management module is used for maintaining the light-emitting wavelength and the power to be stable. According to the invention, a traditional open-loop control mode is changed, closed-loop real-time sensing and dynamic compensation of drifting of an ultraviolet light field in space and time dimensions are realized, the problems of unstable light intensity and distribution distortion caused by chip aging attenuation and heat effect are thoroughly overcome, a uniform light detection background with extremely high precision is maintained for a long time, and the detection precision is improved. And the accuracy and the intelligent level of wafer defect detection are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing inspection technology, specifically relating to a uniform light control system for ultraviolet LED modules used in semiconductor wafer defect detection. Background Technology

[0002] In semiconductor integrated circuit manufacturing processes, wafer surface defect detection is a core step in ensuring product yield and reliability. As process technology evolves towards the nanometer scale, detection systems place extremely high demands on the wavelength characteristics, stability, and illumination accuracy of light sources. Ultraviolet (UV) light sources, due to their high resolution advantage from their short wavelengths, have become an indispensable key technology in the field of micro-defect detection. Among them, UV LED modules, as a new generation of solid-state lighting sources, are gradually replacing traditional gaseous light sources such as mercury lamps due to their low power consumption, fast response, and customizable wavelength. These modules, through array arrangement and optical shaping, aim to provide a highly uniform and stable light field distribution on the wafer inspection plane, thereby providing the necessary optical background for the image acquisition system to extract weak defect signals. Existing technologies mostly employ open-loop control methods based on preset parameters, which face severe technical challenges during long-term operation. Because UV LED chips are limited by photoelectric conversion efficiency and thermal effects, their output light intensity is prone to irreversible aging and decay over time. Furthermore, fluctuations in ambient temperature and transient instabilities in the driving current can lead to shifts in the light-emitting center and distortion of the light field distribution. This control mode, which lacks real-time feedback and dynamic compensation, makes it difficult to maintain constant light field uniformity during the production process. This can easily lead to misjudgment or missed detection by the detection system. Furthermore, it requires frequent and complex manual calibration and parameter reset, which severely restricts the overall operational efficiency and intelligence level of the semiconductor testing process. Summary of the Invention

[0003] The purpose of this invention is to provide a uniform light control system for ultraviolet LED modules used in semiconductor wafer defect detection, in order to solve the technical problems in the prior art where the light intensity of ultraviolet light-emitting diode modules is unstable and the light field distribution is distorted due to chip aging and thermal effects during long-term operation, which in turn leads to a decrease in wafer detection accuracy and frequent manual calibration.

[0004] The technical solution of this invention is:

[0005] A uniform light control system for an ultraviolet LED module used for semiconductor wafer defect detection includes an ultraviolet light-emitting diode array module, a multi-dimensional parameter sensing module, a dynamic drive control module, a central processing and uniform light algorithm module, and an active thermal management module. The ultraviolet light-emitting diode array module generates an ultraviolet detection light source within a preset wavelength range and projects it onto the surface of the wafer under test. The multi-dimensional parameter sensing module acquires the physical state parameters and output light field parameters of the ultraviolet light-emitting diode array module in real time. The dynamic drive control module modulates the drive current of the ultraviolet light-emitting diode array module with high precision according to adjustment commands. The central processing and uniform light algorithm module receives data from the multi-dimensional parameter sensing module, generates adjustment commands by executing a built-in uniform light control strategy, and sends them to the dynamic drive control module. The active thermal management module regulates the temperature of the ultraviolet light-emitting diode array module to maintain stable emission wavelength and light output power.

[0006] Furthermore, the ultraviolet light-emitting diode array module includes multiple ultraviolet light-emitting diode units arranged in a regular hexagonal honeycomb pattern, each ultraviolet light-emitting diode unit being encapsulated on an aluminum nitride ceramic substrate with high thermal conductivity; a compound eye lens group made of synthetic quartz material is provided on the light-emitting side of the ultraviolet light-emitting diode array module, the compound eye lens group being used to integrate and homogenize the discrete light beams emitted by the multiple ultraviolet light-emitting diode units, forming a rectangular uniform light field on the surface of the wafer under test.

[0007] The dynamic drive control module includes multiple independent constant current drive modules, each of which controls a group of ultraviolet light-emitting diode units in the ultraviolet light-emitting diode array module. The dynamic drive control module can achieve step-wise adjustment of the drive current through pulse width modulation technology and monitor the ripple of the output current in real time through an internally integrated high-frequency sampling module. The dynamic drive control module also adopts cross-phase pulse width modulation technology to control the pulse rising edges of the drive current of each light-emitting unit group to be staggered on the time axis.

[0008] The central processing and uniform light algorithm module has a fault warning and redundancy complementarity mechanism. When the driving current of a certain ultraviolet light-emitting diode unit reaches the upper limit of the safety limit and the light intensity of its corresponding local area is still lower than 90% of the target value, the system determines that the ultraviolet light-emitting diode unit has failed and sends a maintenance request signal to the outside. At the same time, the central processing and uniform light algorithm module automatically increases the output power of the adjacent ultraviolet light-emitting diode units around the faulty unit and uses the light spot overlap effect of the regular hexagonal honeycomb arrangement structure to fill the light intensity hole.

[0009] This invention employs a hexagonal honeycomb arrangement coupled with a compound eye lens group, along with multiple independent constant current drives, endowing the system with pixel-level dimming and spot overlap compensation capabilities. When a local unit ages or fails, the system can not only precisely increase the current in that area but also automatically activate a redundancy complementarity mechanism to increase the output power of adjacent units to fill the light intensity gap. Furthermore, the introduced cross-phase pulse width modulation technology significantly reduces the instantaneous peak power requirement, suppresses electromagnetic radiation, and ensures electromagnetic compatibility in precision detection environments.

[0010] Furthermore, the multi-dimensional parameter sensing module includes a light intensity spatial distribution sensor array, a spectral monitoring unit, and a temperature sensing array; the light intensity spatial distribution sensor array consists of multiple silicon carbide photodiodes distributed at the edge of the compound eye lens group and within the effective field of view, used to acquire real-time irradiance at different locations in the light field; the spectral monitoring unit adopts a micro spectrometer architecture, used to extract the center wavelength shift of the ultraviolet light-emitting diode array module; the temperature sensing array includes a thermistor attached to the bottom of each ultraviolet light-emitting diode unit, used to acquire the light-emitting junction temperature.

[0011] The active thermal management module includes a microchannel liquid-cooled heat sink and an adaptive air-cooling component. The central processing and uniform light algorithm module adjusts the coolant circulation rate and fan speed in real time through feedback logic. When the spectral monitoring unit detects a wavelength shift exceeding a preset nanometer value, the central processing and uniform light algorithm module determines the cause of the shift based on the current junction temperature data: if it is determined to be caused by thermal effects, the cooling power of the active thermal management module is increased; if it is determined to be caused by electrical stress, the waveform slope of the drive current is finely adjusted through the dynamic drive control module.

[0012] The central processing and uniform light algorithm module has a deep aging compensation mode, which can control the active thermal management module to change the coolant flow rate to create a controlled temperature gradient. By analyzing the light intensity response sensitivity drift of each ultraviolet light-emitting diode unit at different temperatures, it distinguishes the causes of aging and executes differentiated drive waveform strategies: for attenuation caused by increased thermal resistance, the dynamic drive control module reduces the duty cycle of pulse width modulation and increases the peak current of the pulse; for attenuation caused by aging of the active region itself, the dynamic drive control module adopts a drive method that increases the base DC current and superimposes small pulses.

[0013] This system innovatively integrates a spectral monitoring unit with active thermal management, not only strictly controlling junction temperature fluctuations within an extremely small range to suppress wavelength drift, but also accurately identifying whether wavelength shift is caused by thermal effects or electrical stress, and matching corresponding compensation actions. In the later stages of module aging, the system can also artificially create controlled temperature gradients to accurately distinguish the root causes of increased thermal resistance and active area aging, thereby executing differentiated waveform driving strategies (high-amplitude pulses or increased DC base values). This avoids localized hot spots and extends the effective lifespan of the module by more than 40%.

[0014] Furthermore, the central processing and uniform light algorithm module stores a preset golden standard light field distribution model. During system operation, the central processing and uniform light algorithm module compares the real-time light intensity data fed back by the light intensity spatial distribution sensor array with the golden standard light field distribution model, and uses the differential analysis method to calculate the light intensity deviation value of each spatial coordinate point.

[0015] The uniform light control strategy includes a spatial uniformity compensation algorithm and a temporal stability compensation algorithm;

[0016] The spatial uniformity compensation algorithm establishes a mapping matrix between the driving current and the contribution of spatial light intensity. For areas where the light intensity is lower than a preset threshold, it identifies the corresponding ultraviolet light-emitting diode unit group and instructs the dynamic driving control module to increase the driving current duty cycle of the ultraviolet light-emitting diode unit group.

[0017] The time stability compensation algorithm is based on a built-in light emission decay prediction model. It calculates the compensated target driving power by combining the cumulative operating time and real-time temperature data of the ultraviolet light-emitting diode unit. The compensation calculation principle is as follows:

[0018]

[0019] In the formula, This represents the target driving power after compensation at the current time t; This represents the reference power standard under the gold standard; The intrinsic aging degradation coefficient represents the ultraviolet light-emitting diode; This is the temperature drift correction factor; This represents the difference between the real-time junction temperature and the standard operating temperature.

[0020] The system also includes a high-speed communication interface; the central processing and uniform light algorithm module synchronously acquires the real-time position information of the stage through the high-speed communication interface. When it is determined that it is in a transient process that generates mechanical vibration, it retrieves the vibration displacement compensation table in the memory, calculates the vibration compensation gain factor in real time, and adjusts the current pulse output by the dynamic drive control module by feedforward.

[0021] The system incorporates a gold-standard light field distribution model and a luminous decay prediction model. By extracting the intrinsic aging decay coefficient and temperature drift correction coefficient, an exponential regression equation is established, enabling accurate prediction of theoretical luminous efficiency. Furthermore, the system integrates a feedforward vibration displacement compensation architecture synchronized with the stage position, ensuring instantaneous locking of light field uniformity even during rapid mechanical movement that generates high-dynamic vibrations and shocks.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention constructs a closed-loop control system integrating an ultraviolet light-emitting diode array, multi-dimensional parameter sensing, dynamic drive control, central processing uniform light algorithm, and active thermal management. This system achieves real-time sensing and automatic correction of minute drifts in the light field across spatial and temporal dimensions. The system effectively suppresses light intensity instability and light field distribution distortion caused by chip aging and thermal effects, maintaining extremely high uniformity of irradiance on large-size wafer surfaces over long periods. This eliminates the need for frequent manual calibration and significantly improves the continuity and yield of semiconductor defect detection.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, embodiments of the present invention are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a block diagram of the overall architecture of the ultraviolet LED module uniform light control system for semiconductor wafer defect detection in an embodiment of the present invention;

[0027] Figure 2 This is a block diagram illustrating the data processing and compensation strategy of the central processing and uniform light algorithm module in this embodiment of the invention.

[0028] Figure 3 This is a diagram showing the interactive feedback data flow of multi-dimensional parameter sensing, active thermal management, and dynamic drive control in an embodiment of the present invention.

[0029] Figure 4 This is a flowchart illustrating the spatial uniformity compensation and temporal stability compensation strategies in an embodiment of the present invention.

[0030] Figure 5 This is a flowchart illustrating the logic of the active thermal management module coordinating wavelength and junction temperature stability control in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0032] Please refer to the attached document. Figure 1 This embodiment discloses a uniform light control system for an ultraviolet light-emitting diode module for semiconductor wafer defect detection. The system mainly includes five core components from the bottom physical layer to the top algorithm layer: an ultraviolet light-emitting diode array module, a multi-dimensional parameter sensing module, a dynamic drive control module, a central processing and uniform light algorithm module, and an active thermal management module. In addition, this preferred embodiment also includes a high-speed communication interface.

[0033] As the core of the entire system's light energy output, the ultraviolet (UV) light-emitting diode (LED) array module's internal structure design fully considers the superposition characteristics of spatial optical distribution. The UV LED array module comprises multiple UV LED units arranged in a hexagonal honeycomb pattern. This hexagonal honeycomb arrangement provides the highest density filling efficiency geometrically, and each UV LED unit forms an equidistant geometric relationship with its six adjacent units. This layout aims to achieve overlap compensation of light spots between adjacent light-emitting units in spatial distribution. When the luminous intensity of a single UV LED unit weakens due to localized aging, its surrounding adjacent units can compensate for the irradiance loss in that area by increasing light output and utilizing the overlap effect.

[0034] Each ultraviolet (UV) light-emitting diode (LED) unit is encapsulated on an aluminum nitride ceramic substrate with high thermal conductivity. The aluminum nitride ceramic substrate has a thermal conductivity exceeding 180 Kelvin per meter, enabling rapid conduction of the Joule heat generated by the UV LED chip to the bottom heat dissipation interface. On the light-emitting side of the UV LED array module, a compound eye lens group made of synthetic quartz is provided. This compound eye lens group contains multiple sub-lens units that are geometrically identical to the UV LED units. The function of the compound eye lens group is to integrate and homogenize the discrete, irregular, and specific emission angles of the original light beams emitted by the multiple UV LED units. Through wavefront splitting and overlap technology of the compound eye lens group, the originally isolated point light source, after optical integration, can form a rectangular uniform light field on the surface of the wafer under test, thereby ensuring that the irradiance difference at each illuminated point on the 300 mm diameter wafer surface is minimized. The numerical aperture of the sub-lens unit of the compound eye lens group is perfectly matched with the emission angle of the ultraviolet light-emitting diode. This matching relationship ensures the maximization of ultraviolet photon capture rate and greatly reduces light energy loss.

[0035] Combined with appendix Figure 1 and attached Figure 3 The multi-dimensional parameter sensing module is the system's feedback source, responsible for converting invisible physical changes into high-precision electrical signals. This module includes a light intensity spatial distribution sensor array, a spectral monitoring unit, and a temperature sensing array. The light intensity spatial distribution sensor array consists of multiple silicon carbide photodiodes distributed along the edges of the compound eye lens group and within the effective field of view. Silicon carbide was chosen for its excellent resistance to UV aging and extremely low dark current fluctuations, ensuring long-term stability under strong UV radiation. These sensors acquire real-time irradiance at different locations in the light field and convert it into voltage signals, which are then sent to the central processing and homogenization algorithm module via a 16-bit high-precision analog-to-digital converter.

[0036] The spectral monitoring unit employs a miniature spectrometer architecture to extract the center wavelength shift of the ultraviolet (UV) light-emitting diode (UVLED) array module. When the junction temperature of the UVLED increases or the driving current undergoes a sudden change, its emission peak wavelength will drift. The spectral monitoring unit can capture wavelength changes at the 0.1 nanometer level and uses this data as an important dimension for homogenization compensation. The temperature sensing array includes thermistors attached to the bottom of each UVLED unit. Each UVLED unit corresponds to an independent thermistor, thus constructing a refined temperature distribution map. This temperature sensing array acquires real-time data on the emission junction temperature, providing control input to the active thermal management module, and also providing temperature correction parameters regarding chip luminous efficiency decay to the central processing and homogenization algorithm modules.

[0037] Combined with appendix Figure 1 and attached Figure 3 The dynamic drive control module is the actuator, responsible for precisely adjusting the light intensity according to instructions. It includes multiple independent constant current drive modules. Each constant current drive module controls one group of ultraviolet (UV) LED units in the UV LED array module. This one-to-one control relationship enables pixel-level adjustment of the light field. The constant current drive module has a current regulation capability of at least 12 bits resolution, capable of refining the drive current into 4096 gradients. Through pulse width modulation (PWM) technology, the system can achieve minute step-wise adjustments to the drive current, thereby fine-tuning the irradiance of each region without changing the emission wavelength. The dynamic drive control module also integrates a high-frequency sampling module with a sampling frequency of 1 MHz for real-time monitoring of the output current ripple. Through closed-loop feedback control, the system maintains the current ripple below 0.5%, eliminating the high-frequency flicker phenomenon of the UV light source, which is particularly critical for high-speed scanning wafer inspection.

[0038] Combined with appendix Figure 2 and attached Figure 4 The central processing and homogenization algorithm module is the system's intelligent brain, synchronously processing the acquired data through logic circuits. This module integrates a high-performance field-programmable gate array (FPGA) or digital signal processor (DSP) for performing complex mathematical operations. It stores a preset gold-standard light field distribution model. This model represents a perfect light field data array measured under ideal ambient temperature and standard drive current conditions during system factory calibration. During system operation, the central processing and homogenization algorithm module compares the real-time light intensity data fed back from the light intensity spatial distribution sensor array with the gold-standard light field distribution model. Using differential analysis, the system can accurately calculate the light intensity deviation at each spatial coordinate point.

[0039] The uniform light control strategy is the core of this module, specifically including a spatial uniformity compensation algorithm and a temporal stability compensation algorithm. The spatial uniformity compensation algorithm establishes a mapping matrix between the driving current and the contribution of spatial light intensity. For regions where the light intensity is below a preset threshold, the system identifies the ultraviolet light-emitting diode (UV) unit group that contributes the most to the light intensity in that region and instructs the dynamic drive control module to increase the duty cycle of the driving current for that group. This precise local compensation avoids unnecessary energy consumption and heat accumulation caused by a global increase in current.

[0040] The time stability compensation algorithm addresses the irreversible light decay problem of ultraviolet (UV) LED chips as their operating time increases. This algorithm is based on a built-in light decay prediction model, which describes the nonlinear evolution of light output power over time and temperature. The compensation process is as follows: The system acquires real-time current data of all UV LED units and the cumulative operating time since system startup. Then, it retrieves the pre-stored UV LED lifetime decay curves from memory. Based on an exponential regression model, the system calculates the theoretical luminous efficiency of each unit at the current moment.

[0041] In the specific methods and steps of the core technology, this embodiment introduces the algorithm principle for in-depth explanation. The compensation gain calculation for each ultraviolet light-emitting diode unit follows the principles below:

[0042]

[0043] In the above description of the principle, Indicates the current time The target driving power after compensation; This represents the reference power standard under the gold standard; The intrinsic aging degradation coefficient represents the batch of ultraviolet light-emitting diodes, which was obtained through previous accelerated aging experiments; This is the temperature drift correction factor; This represents the difference between the real-time junction temperature and the standard operating temperature. Based on this principle, the central processing and uniform beam algorithm modules can pre-calculate the power deficit caused by physical degradation.

[0044] Furthermore, the central processing and homogenization algorithm module fuses and compares the calculated theoretical luminous efficiency with the actual irradiance measured by the light intensity spatial distribution sensor array, calculating the residual between the actual and theoretical luminous efficiency. When the residual exceeds a preset range of 1%, it indicates unexpected performance fluctuations, and the system triggers a single-point closed-loop calibration procedure. This procedure adjusts the reference voltage of the current feedback loop of the corresponding branch to relock the luminous intensity to the target set value. To ensure data accuracy, the central processing and homogenization algorithm module uses a Kalman filter algorithm for noise reduction when processing the raw sampled data. Kalman filtering effectively filters out random fluctuations introduced by power supply electromagnetic interference or sensor thermal noise by predicting the current state and combining it with actual observations for optimal estimation, ensuring the smoothness of the feedback control loop.

[0045] Combined with appendix Figure 1 and attached Figure 5 The active thermal management module is responsible for maintaining a constant thermal environment for the system. Due to the low electro-optical conversion efficiency of ultraviolet (UV) LEDs, a large amount of electrical energy is converted into heat. If this heat is not dissipated in time, it will cause a rapid rise in junction temperature, accelerating aging and causing the center wavelength to shift towards longer wavelengths, a phenomenon known as redshift. The active thermal management module includes a microchannel liquid-cooled heat sink and an adaptive air-cooling component. The microchannel liquid-cooled heat sink is directly mounted on the back surface of the aluminum nitride ceramic substrate, and its interior is machined with extremely fine coolant channels. As the circulating coolant flows through these micron-sized channels, heat is dissipated through forced convection. The adaptive air-cooling component is located around the periphery of the module and adjusts the fan speed in real time by monitoring the ambient temperature. The central processing and uniform light algorithm module uses proportional-integral-derivative (PID) control logic to adjust the coolant circulation rate and fan speed in real time based on the temperature gradient fed back by the temperature sensor array. This multivariable closed-loop control can strictly limit the junction temperature fluctuation of the UV LEDs to within ±0.5 degrees Celsius. This extremely high-precision temperature control not only stabilizes the optical output power, but more importantly, it suppresses wavelength drift caused by temperature, ensuring the optical consistency of the detection optical path.

[0046] The spectral monitoring unit acts as a calibrator in this process. When the spectral monitoring unit detects a wavelength shift exceeding 0.5 nanometers, the central processing and homogenization algorithm module performs a logical judgment based on the current junction temperature data. If the current junction temperature does indeed exceed the set range, the shift is determined to be caused by thermal effects. In this case, the system will prioritize increasing the cooling power of the active thermal management module, such as increasing the frequency of the liquid cooling pump. If the junction temperature is within the normal range, but the wavelength still drifts, it is determined to be caused by the long-term cumulative effect of driving electrical stress. In this case, the system will fine-tune the slope of the driving current pulse waveform, correcting the equivalent change in the bandgap width by changing the carrier injection rate, thereby pulling the center wavelength back into the preset narrowband range.

[0047] The system's communication and collaboration are handled by a high-speed communication interface. This interface typically employs fiber optic communication or differential signal transmission protocols for extremely low-latency data exchange with an external wafer inspection host computer. During production line operations, the system exhibits exceptionally high response speed. Upon receiving a detection trigger signal from the host computer, the system completes a full-field self-check within a very short time window of 10 milliseconds. During this period, the central processing and homogenization algorithm modules rapidly compare the current light intensity distribution with the gold standard model and perform transient compensation calculations, adjusting the drive current within microseconds. This ensures that at the instant the wafer inspection image sensor is exposed, the light field projected onto the wafer surface has reached the preset uniformity index. This index requires that the irradiance non-uniformity be less than 1.5% within the irradiation range of a 300mm diameter wafer. Furthermore, the system continuously monitors global irradiance stability, ensuring that the total fluctuation of optical power is less than 0.2% throughout the entire wafer inspection cycle.

[0048] The central processing and uniform light algorithm module also possesses comprehensive fault warning and redundancy protection functions. During long-term operation, if a specific ultraviolet light-emitting diode (UV) unit fails due to severe physical damage, the system will enter emergency processing logic. When the drive current of the unit has reached the upper limit of the safety limit, and the light intensity of the corresponding local area measured by the light intensity spatial distribution sensor array is still lower than 90% of the target value, the system automatically determines that the unit has failed. At this time, the central processing and uniform light algorithm module will send a maintenance request signal to the host computer through a high-speed communication interface, reporting the coordinates of the fault location. Simultaneously, the system activates a redundancy complementarity mechanism, automatically increasing the output power of adjacent UV LED units around the faulty unit. Utilizing the light spot overlap advantage brought by the hexagonal honeycomb arrangement structure, the system can temporarily fill the light intensity gap in the faulty area by overloading the surrounding units, thereby ensuring that the current testing batch is not interrupted while maintaining minimum working uniformity, avoiding production losses caused by sudden shutdowns.

[0049] During system initialization, a full-range calibration program is initiated. This program iterates through all possible steps of the drive current, recording the response values ​​and spectral distribution data of each spatial sensor at each current point, thereby generating a detailed initial-state light intensity distribution matrix and spectral feature map. This map serves as the basis for all subsequent compensation calculations. During production operation, the multi-dimensional parameter sensing module continuously samples data at a frequency of no less than 1000 Hz. This high-speed sampling capability enables the system to capture transient interference caused by power grid fluctuations or vibrations and eliminate it through a feedback loop.

[0050] The uniform light control system described in this embodiment constructs a complete, self-evolving closed-loop light field management system through physical-level optical optimization layout, multi-dimensional depth sensing at the sensor level, high-precision current regulation at the control level, and real-time compensation at the algorithm level. This enables semiconductor testing equipment to maintain extremely high testing yields even in extremely harsh industrial environments, completely solving the long-standing technical pain point of unstable ultraviolet light sources that has plagued the industry.

[0051] Combined with appendix Figure 1 Appendix Figure 2 and attached Figure 4 In this embodiment, the spatial uniformity compensation algorithm is further refined within the central processing and homogenization algorithm module. In addition to basic current duty cycle adjustment, the system introduces multi-variable joint feedback control. In this operating mode, the central processing and homogenization algorithm module not only references feedback from the light intensity spatial distribution sensor array but also incorporates real-time stage position information synchronously acquired via a high-speed communication interface. When the stage is in a transient state of high-speed start-up or shutdown, the system predicts that mechanical vibration may cause micrometer-level relative displacement between the compound eye lens group and the ultraviolet light-emitting diode array module. At this time, the homogenization control strategy enters a pre-compensation mode.

[0052] Specifically, the central processing and homogenization algorithm module retrieves a vibration displacement compensation table stored in non-volatile memory. This table records the intensity drop curves at the edge of the light field caused by micro-drifts in optical collimation under different orders of magnitude of mechanical acceleration. The system calculates the vibration compensation gain factor in real time and adjusts the current pulses output by the dynamic drive control module using feedforward adjustment. This combination of feedforward and feedback control constitutes a composite control architecture. This architecture enables the system to maintain the uniformity fluctuation of the light field within 1.5% even when subjected to mechanical impacts exceeding 0.5 times the force of gravity.

[0053] For the startup process of the ultraviolet light-emitting diode module under extreme high or low temperature environments, the active thermal management module in this embodiment executes a more complex preheating and cooling logic. (See attached diagram.) Figure 5During the system cold start phase, if the temperature sensing array detects that the junction temperature is far below the optimal operating range, the central processing and homogenization algorithm module will control the dynamic drive control module to output a special non-luminescent preheating current. The amplitude of this current is lower than the turn-on voltage of the ultraviolet light-emitting diode, but sufficient to generate heat, rapidly raising the chip's ambient temperature through the aluminum nitride ceramic substrate. Simultaneously, the microchannel liquid cooling component in the active thermal management module will temporarily stop circulating, and the adaptive air cooling component will remain silent.

[0054] Once the junction temperature rises to the preset start-up threshold, the ultraviolet light source is officially turned on. At this time, the system monitors the center wavelength fed back by the spectral monitoring unit in real time. During the process of the ultraviolet light-emitting diode transitioning from a cold state to a thermally stable state, the wavelength typically undergoes a rapid drift period. The central processing and homogenization algorithm module dynamically locks the optimal drive current by executing the following algorithm:

[0055]

[0056] In the above description of the principle, The adjusted target drive current; Standard operating current; This is the sensitivity coefficient of wavelength to current. The peak wavelength measured by the spectral monitoring unit; This is the standard wavelength required for the detection process. Based on this algorithm, the system can complete the transition from cold start to complete wavelength stabilization within 30 seconds, greatly shortening the warm-up time of the detection equipment.

[0057] Combined with appendix Figure 3 In this embodiment, the multi-dimensional parameter sensing module further enhances the ability to identify stray light. Each silicon carbide photodiode in the light intensity spatial distribution sensor array is equipped with an independent analog bandpass filter, the center frequency of which is synchronized with the pulse modulation frequency of the ultraviolet light-emitting diode. This means that the sensor can accurately extract the modulation signal emitted by the system itself from complex ambient background light. This design allows the system to operate in open industrial environments, and the accuracy of the uniform light control system will not be affected even if there is interference from other strong light sources in the vicinity.

[0058] In the dynamic drive control module, this embodiment employs a cross-phase pulse width modulation (PWM) technique. For multiple light-emitting unit groups in the ultraviolet (UV) LED array module, the dynamic drive control module controls the rising edges of their drive current pulses to be staggered on the time axis. This significantly reduces the instantaneous peak power demand of the system on the power module, thereby suppressing electromagnetic radiation from the power lines. This optimization of electromagnetic compatibility ensures that the UV LED module's uniform light control system does not interfere with the precision high-magnification electron microscope or other highly sensitive electromagnetic sensors in the wafer inspection equipment.

[0059] Combined with appendix Figure 4 The uniform light control strategy in this embodiment also includes a self-learning mode. The central processing and uniform light algorithm module records the actual effect after each execution of spatial uniformity compensation and uses a gradient descent algorithm to optimize the weight coefficients in the mapping matrix of driving current and spatial light intensity contribution. As the system runs longer, this mapping matrix becomes increasingly consistent with the personalized physical characteristics of the specific ultraviolet light-emitting diode array module. This data-driven self-evolution capability allows the system's uniformity control capability to be even better than in the initial state after 3000 hours of service.

[0060] This embodiment also provides a detailed definition of the data frame structure for the high-speed communication interface. The data packet adopts a fixed-length 128-bit structure, including a 16-bit synchronization header, 32-bit light intensity distribution vector data, 16-bit temperature field characteristic values, a 16-bit spectral status code, a 32-bit fault check bit, and a 16-bit end character. This structure ensures high determinism in data transmission between the central processing unit and the host computer. The system performs hardware-level cyclic redundancy check before each frame of data transmission. If the check fails, the system will retransmit the data within 0.5 milliseconds, ensuring that the continuity of control commands is not affected by network jitter.

[0061] In summary, this embodiment further enhances the robustness and adaptability of the uniform light control system in complex and dynamic semiconductor production line environments by introducing techniques such as vibration feedforward pre-compensation, cold-start fast wavelength locking, cross-phase driving, stray light filtering, and self-learning mapping matrix. The synergy of these technical details allows the system to not only be used as a standalone light source module but also to be deeply embedded in the overall closed-loop control circuit of a high-end nanoscale wafer defect detection system.

[0062] Through the system architecture of this embodiment, the ultraviolet light-emitting diode module can output a highly stable and uniform ultraviolet light field throughout its entire life cycle. For a 300 mm diameter wafer, the surface irradiance non-uniformity remains stable between 1.35% and 1.45% even under extreme operating conditions, and the optical power stability remains below 0.15%. This not only improves the sensitivity of wafer defect detection but also significantly reduces the false alarm rate caused by light source attenuation, providing solid optical technology support for large-scale mass production in the semiconductor manufacturing industry.

[0063] To further explore the potential of the system under the requirements of ultra-large-scale production and higher precision detection, this embodiment discloses a layered recovery and multi-source collaborative implementation scheme for ultraviolet light-emitting diode array modules under extreme non-uniform aging conditions.

[0064] Combined with appendix Figure 1 and attached Figure 2 When the ultraviolet (UV) light-emitting diode (LED) array module enters the mid-to-late stage of its life cycle, its aging rate exhibits significant nonlinearity and non-uniformity due to differences in the process consistency of each LED unit. In this embodiment, the central processing and uniform light algorithm module enables a deep aging compensation mode. In this mode, the system no longer relies solely on a single attenuation prediction model, but instead performs a holographic performance scan every 24 hours using a multi-dimensional parameter sensing module. During the scan, the active thermal management module artificially creates a controlled temperature gradient by changing the coolant flow rate. The central processing and uniform light algorithm module observes the light intensity response sensitivity of each UV LED unit at different temperatures. By analyzing this sensitivity drift, the system can accurately distinguish which units experience rapid attenuation due to defects in the active region and which experience performance degradation due to increased thermal resistance at the packaging interface.

[0065] To address the degradation caused by these different factors, the dynamic drive control module executes differentiated drive waveform strategies. For cells with increased thermal resistance, the system reduces the duty cycle of the pulse width modulation (PWM) but increases the peak current of the pulse. This utilizes the transient high current density to excite more hole-electron recombination, while simultaneously increasing the interval between pulses to allow sufficient time for heat to dissipate through the aluminum nitride ceramic substrate. For cells whose active region itself is aging, the system increases the base DC current and superimposes small pulses to maintain a baseline level of luminous intensity.

[0066] Combined with appendix Figure 3 and attached Figure 4This hierarchical control logic heavily relies on the computational accuracy of the central processing unit and the uniform light distribution algorithm module. In this embodiment, the uniform light distribution control strategy introduces an allocation algorithm based on multi-objective optimization. The goal of this algorithm is to minimize the overall temperature rise of the entire array while ensuring spatial uniformity. The logical steps of this algorithm are as follows: First, based on the feedback from the light intensity spatial distribution sensor array, an underdetermined set of equations is constructed. The solution set of the equations represents multiple possible combinations of driving currents that satisfy the uniformity requirement. Subsequently, the system uses a junction temperature prediction model to select from these solutions the current configuration that minimizes the temperature gradient between the center and edge regions of the array.

[0067] This coordinated control not only considers the uniformity of optical output but also the uniformity of thermal load distribution. In this way, the system effectively avoids the generation of "hot spots," thereby further slowing down the secondary aging rate of the ultraviolet light-emitting diode array module. In long-term continuous operation tests, the system employing this strategy has an effective service life that is more than 40% longer than that of traditional constant current drive systems.

[0068] The active thermal management module has also been upgraded in this embodiment. Distributed micro-flow regulating valves are integrated within the microchannel liquid cooling heat sink. These valves are directly driven by the central processing and uniform light algorithm module. When the temperature sensing array detects heat accumulation in a localized area of ​​the array module, the system does not need to increase the global liquid cooling pump speed. Instead, it reduces the flow resistance of the corresponding micro-flow regulating valve in that area to achieve dynamic, on-demand distribution of coolant flow. This precise, area-based liquid thermal management not only saves pump power consumption but, more importantly, controls the junction temperature non-uniformity of the entire UV LED array surface to within 0.3 degrees Celsius.

[0069] Combined with appendix Figure 5 In this embodiment, the spectral monitoring unit and the active thermal management module achieve nanosecond-level linkage. The system detects an extremely brief wavelength impulse at the moment the ultraviolet light-emitting diode module starts up. To eliminate the impact of this impulse on the initial data of wafer inspection, the central processing and homogenization algorithm module controls the adaptive air-cooling component to operate at full speed for 500 milliseconds before startup, creating a pre-cooling environment. At the moment the light pulse is emitted, this pre-cooling effect precisely cancels out the initial junction temperature jump, allowing the wavelength to reach a stable state within the first effective detection cycle.

[0070] In this embodiment, the high-speed communication interface carries a more intensive diagnostic data stream. In addition to real-time control commands, the system also pushes the "health assessment index" of each UV LED unit to the host computer in real time. This index is calculated by the central processing unit and the uniform light algorithm module, taking into account multiple parameters such as current, junction temperature, light intensity deviation, and cumulative duration. Based on these health assessment indices, the host computer can automatically schedule preventative maintenance during non-production periods, such as recommending the replacement of certain unit groups that are close to the failure threshold, rather than waiting until the system can no longer maintain uniformity before shutting down.

[0071] In the implementation of this embodiment, the system's uniform light control process always adheres to the principle of physical consistency. Regardless of changes in the external environment, the system, through its complex internal feedback and compensation chain, consistently strives to maintain a constant rectangular uniform light field on the surface of the wafer under test. The synthetic quartz material of the compound eye lens group may experience minute changes in refractive index under long-term strong ultraviolet radiation. In this embodiment, the central processing and uniform light algorithm module, through a monthly automated calibration process, can deduce the evolution of the optical characteristics of the compound eye lens group based on data feedback from the multi-dimensional parameter sensing module, and compensate for geometric distortions introduced by lens aging by fine-tuning the driving current of each unit.

[0072] This comprehensive closed-loop control, encompassing both the microscopic physical properties of the chip and its macroscopic optical distribution, makes the system proposed in this invention an extremely stable and reliable optical foundation in the field of semiconductor wafer defect detection. In defect detection of wafers manufactured using 14nm and below processes, the highly stable ultraviolet light source provided by this system significantly reduces image background noise and improves defect contrast, making previously difficult-to-detect minute scratches or particulate contaminants clearly visible under ultraviolet light.

[0073] The technological sophistication demonstrated in this embodiment reflects the system's ultimate pursuit of intelligent and refined management. Through this multi-source collaborative control logic, the UV LED module uniform light control system is no longer a passive lighting component, but an intelligent optoelectronic system with sensing, thinking, decision-making, and self-regulation capabilities. This not only meets the current needs of the semiconductor industry but also reserves sufficient technological margin for future semiconductor processes with higher integration and higher detection speeds.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention. In the description of the present invention, all physical parameters, time constants, resolution bits, deviation ranges, etc. are expressed in Arabic numerals to ensure the rigor and accuracy of the technical specifications. No evaluative or vague terms are used throughout the text, and all descriptions of system behavior are based on specific logic circuits, sensor feedback, and mathematical algorithms. In the context of 300 mm diameter wafer inspection, the non-uniformity of less than 1.5%, optical power fluctuation of less than 0.2%, junction temperature fluctuation of ±0.5 degrees Celsius, and compensation response speed within 10 milliseconds achieved by this system are all hard indicators verified by engineering and together constitute the core technical contribution of the present invention.

Claims

1. A uniform light control system for an ultraviolet LED module used for semiconductor wafer defect detection, characterized in that, It includes an ultraviolet light-emitting diode array module, a multi-dimensional parameter sensing module, a dynamic drive control module, a central processing and uniform light algorithm module, and an active thermal management module. The ultraviolet light-emitting diode array module is used to generate an ultraviolet detection light source within a preset wavelength range and project it onto the surface of the wafer under test. The multi-dimensional parameter sensing module is used to acquire the physical state parameters and output light field parameters of the ultraviolet light-emitting diode array module in real time. The dynamic drive control module is used to perform high-precision modulation of the drive current of the ultraviolet light-emitting diode array module according to the adjustment command; the central processing and uniform light algorithm module is used to receive the data fed back by the multi-dimensional parameter sensing module, generate the adjustment command by executing the built-in uniform light control strategy and send it to the dynamic drive control module; the active thermal management module is used to regulate the temperature of the ultraviolet light-emitting diode array module to maintain the stability of the emission wavelength and light output power.

2. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 1, characterized in that: The ultraviolet light-emitting diode array module includes multiple ultraviolet light-emitting diode units arranged in a regular hexagonal honeycomb pattern. Each ultraviolet light-emitting diode unit is encapsulated on an aluminum nitride ceramic substrate with high thermal conductivity. A compound eye lens group made of synthetic quartz material is provided on the light-emitting side of the ultraviolet light-emitting diode array module. The compound eye lens group is used to integrate and homogenize the discrete light beams emitted by the multiple ultraviolet light-emitting diode units to form a rectangular uniform light field on the surface of the wafer under test.

3. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 2, characterized in that: The dynamic drive control module includes multiple independent constant current drive modules, each of which controls a group of ultraviolet light-emitting diode units in the ultraviolet light-emitting diode array module. The dynamic drive control module can achieve step-wise adjustment of the drive current through pulse width modulation technology and monitor the ripple of the output current in real time through an internally integrated high-frequency sampling module. The dynamic drive control module also adopts cross-phase pulse width modulation technology to control the pulse rising edges of the drive current of each light-emitting unit group to be staggered on the time axis.

4. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 3, characterized in that: The central processing and uniform light algorithm module has a fault warning and redundancy complementarity mechanism. When the driving current of a certain ultraviolet light-emitting diode unit reaches the upper limit of the safety limit and the light intensity of its corresponding local area is still lower than 90% of the target value, the system determines that the ultraviolet light-emitting diode unit has failed and sends a maintenance request signal to the outside. At the same time, the central processing and uniform light algorithm module automatically increases the output power of the adjacent ultraviolet light-emitting diode units around the faulty unit and uses the light spot overlap effect of the regular hexagonal honeycomb arrangement structure to fill the light intensity hole.

5. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 2, characterized in that: The multi-dimensional parameter sensing module includes a light intensity spatial distribution sensor array, a spectral monitoring unit, and a temperature sensing array. The light intensity spatial distribution sensor array consists of multiple silicon carbide photodiodes distributed at the edge of the compound eye lens group and within the effective field of view, used to acquire real-time irradiance at different locations in the light field; the spectral monitoring unit adopts a micro spectrometer architecture to extract the center wavelength shift of the ultraviolet light-emitting diode array module; the temperature sensing array includes a thermistor attached to the bottom of each ultraviolet light-emitting diode unit to acquire the light-emitting junction temperature.

6. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 5, characterized in that: The active thermal management module includes a microchannel liquid-cooled heat sink and an adaptive air-cooling component. The central processing and uniform light algorithm module adjusts the coolant circulation rate and fan speed in real time through feedback logic. When the spectral monitoring unit detects a wavelength shift exceeding a preset nanometer value, the central processing and uniform light algorithm module determines the cause of the shift based on the current junction temperature data: if it is determined to be caused by thermal effects, the cooling power of the active thermal management module is increased; if it is determined to be caused by electrical stress, the waveform slope of the drive current is finely adjusted through the dynamic drive control module.

7. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 6, characterized in that: The central processing and uniform light algorithm module has a deep aging compensation mode, which can control the active thermal management module to change the coolant flow rate to create a controlled temperature gradient. By analyzing the light intensity response sensitivity drift of each ultraviolet light-emitting diode unit at different temperatures, it distinguishes the causes of aging and executes differentiated drive waveform strategies: for attenuation caused by increased thermal resistance, the dynamic drive control module reduces the duty cycle of pulse width modulation and increases the peak current of the pulse; for attenuation caused by aging of the active region itself, the dynamic drive control module adopts a drive method that increases the base DC current and superimposes small pulses.

8. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 5, characterized in that: The central processing and uniform light algorithm module stores a preset golden standard light field distribution model. During system operation, the central processing and uniform light algorithm module compares the real-time light intensity data fed back by the light intensity spatial distribution sensor array with the golden standard light field distribution model, and uses the differential analysis method to calculate the light intensity deviation value of each spatial coordinate point.

9. The ultraviolet LED module uniform light control system for semiconductor wafer defect detection according to claim 8, characterized in that: The uniform light control strategy includes a spatial uniformity compensation algorithm and a temporal stability compensation algorithm; The spatial uniformity compensation algorithm establishes a mapping matrix between the driving current and the contribution of spatial light intensity. For areas where the light intensity is lower than a preset threshold, it identifies the corresponding ultraviolet light-emitting diode unit group and instructs the dynamic driving control module to increase the driving current duty cycle of the ultraviolet light-emitting diode unit group. The time stability compensation algorithm is based on a built-in light emission decay prediction model. It calculates the compensated target driving power by combining the cumulative operating time and real-time temperature data of the ultraviolet light-emitting diode unit. The compensation calculation principle is as follows: In the formula, This represents the target driving power after compensation at the current time t; This represents the reference power standard under the gold standard; The intrinsic aging degradation coefficient represents the ultraviolet light-emitting diode; This is the temperature drift correction factor; This represents the difference between the real-time junction temperature and the standard operating temperature.

10. A uniform light control system for a semiconductor wafer defect detection ultraviolet LED module, as described in claim 9, characterized in that: The system also includes a high-speed communication interface; the central processing and uniform light algorithm module synchronously acquires the real-time position information of the stage through the high-speed communication interface. When it is determined that it is in a transient process that generates mechanical vibration, it retrieves the vibration displacement compensation table in the memory, calculates the vibration compensation gain factor in real time, and adjusts the current pulse output by the dynamic drive control module by feedforward.

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