Scribing system and method for monitoring and adjusting laser energy in real time

Abstract

The invention discloses a scribing system and method for monitoring and adjusting laser energy in real time, and the system comprises a spectroscope disposed below a laser, the spectroscope divides a laser beam into a main laser beam and a monitoring laser beam, the path of the monitoring laser beam is provided with a laser energy detector, and the laser energy detector is connected with a control unit. The control unit is further connected with the laser. The method comprises the following steps: firstly, calibrating the system, establishing a corresponding relation between an energy value of a monitoring laser beam and actual energy of a main laser beam, converting a target laser energy value into a target monitoring energy value of the monitoring laser beam, and setting an energy fluctuation tolerance range; and then the laser is started to perform scribing operation, and the control unit regulates and controls the laser according to the real-time monitoring energy value and the comparison of the real-time monitoring energy value and the target monitoring energy value until the laser scribing operation is completed. According to the invention, the problem of product yield loss caused by single calibration before processing and incapability of monitoring laser output energy during processing in real time in the existing scribing technology is solved.

Description

Technical Field

[0001] This invention belongs to the field of laser scribing technology, specifically relating to a scribing system and method for real-time monitoring and adjustment of laser energy. Background Technology

[0002] Laser scribing technology, with its outstanding advantages such as high processing efficiency, small heat-affected zone, and excellent processing precision, has become a core process for cutting and separating hard and brittle materials such as wafers, glass, and ceramics in industries such as semiconductors, microelectronics, and optoelectronics. It is widely used in the production and manufacturing of various precision electronic components. During laser scribing, the stability of laser energy is a key factor determining the scribing quality. It directly affects core processing indicators such as groove depth, groove width, and the degree of edge chipping, thus determining the performance and yield of the final product.

[0003] Currently, the mainstream laser scribing process in the industry is divided into the following three stages: 1. Energy calibration before processing: During the equipment debugging stage or before the start of batch processing, the operator will use an independent laser energy detector to measure the initial output energy of the laser at the laser output end once. 2. Power matching adjustment: The laser scribing equipment compares the measured initial laser energy with the preset target energy value in the process recipe, and adjusts the output power of the laser accordingly so that the actual laser output energy is close to or completely matches the process setting value. 3. Batch scribing: After power matching is completed, the equipment starts the preset laser scribing program, drives the motion platform to move the workpiece relative to the laser beam, and completes the scribing of the entire batch of workpieces.

[0004] However, the aforementioned traditional technical solutions have significant drawbacks in practical applications. Firstly, they only perform a one-time energy calibration before processing, failing to dynamically monitor the laser energy during the process. During continuous processing, factors such as constant changes in laser operating temperature, aging and decay of the components themselves, and contamination or performance degradation of optical lenses can all cause drifting fluctuations or a continuous decrease in laser output energy. This energy deviation cannot be detected in time, leading to significant differences in the dicing quality of workpieces in the same batch. For example, the groove depth may differ between workpieces processed in the preceding and subsequent processes, and the degree of edge chipping may vary significantly, resulting in numerous quality defects such as bicrystalline anomalies and causing severe product yield losses.

[0005] On the other hand, in traditional solutions, laser energy detection and adjustment are separate and discontinuous operations. Energy retesting and secondary calibration are usually only initiated after the entire batch of workpieces has been processed, or when obvious quality defects have appeared. This lack of proactive intervention capability for energy anomalies that occur during processing means that defective workpieces that have already been processed cannot be recovered, further exacerbating the loss of product yield. Summary of the Invention

[0006] The purpose of this invention is to provide a dicing system that can monitor and adjust laser energy in real time, which solves the problem that existing dicing technologies only perform a single calibration before processing and cannot monitor the laser output energy during processing in real time, resulting in product yield loss.

[0007] Another objective of this invention is to provide a dicing method for real-time monitoring and adjustment of laser energy.

[0008] The first technical solution adopted in this invention is a dicing system for real-time monitoring and adjustment of laser energy, including a beam splitter located below the laser. The beam splitter is positioned on the laser beam path and divides the laser beam into a main laser beam for dicing operations and a monitoring laser beam for energy monitoring. A laser energy detector is installed on the path of the monitoring laser beam. The laser energy detector is signal-connected to a control unit, which is also signal-connected to the laser. The laser energy detector receives the monitoring laser beam and acquires its energy value. The control unit adjusts the laser energy output by the laser based on the acquired energy value.

[0009] The first technical solution of the present invention is further characterized in that, The control unit is a PLC controller or an industrial computer.

[0010] The beam splitter is an optical lens with an adjustable beam splitting ratio. The main laser beam is transmitted light with a higher energy percentage than the monitoring laser beam, and the monitoring laser beam is reflected light with a lower energy percentage than the main laser beam.

[0011] The beam splitter has a splitting ratio of 90:10, with the main laser beam accounting for 90% of the energy and the monitoring laser beam accounting for 10%.

[0012] The second technical solution adopted in this invention is a dicing method for real-time monitoring and adjustment of laser energy, comprising the following steps: S1. The system is calibrated to establish the correspondence between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam reaching the workpiece surface. The target laser energy value is converted into the target monitoring energy value of the monitoring laser beam, and the energy fluctuation tolerance range is set. S2, the laser is started. The laser emits laser light and it is split into two paths by a beam splitter. The main laser beam performs a slicing action, and at the same time the laser energy detector receives and measures the energy of the laser beam in real time. S3, the control unit reads the real-time monitoring energy value of the laser energy detector in real time, compares it with the target monitoring energy value, and adjusts the laser based on the comparison result; S4. Repeat steps S2 and S3 to complete the laser scribing operation.

[0013] The second technical solution of the present invention is further characterized in that, In step S1, establishing the correspondence between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam reaching the workpiece surface involves first determining the splitting ratio k of the beam splitter, and then obtaining the optical path loss coefficient θ of the main laser beam from the beam splitter to the workpiece surface through an idle calibration procedure. 主 The optical path loss coefficient θ of the laser beam from the beam splitter to the laser energy detector is monitored. 监 Based on k, θ 主 and θ 监 A linear correspondence is established between the two, as shown in the following equation: ; In the formula, The actual energy of the main laser beam reaching the workpiece surface; Monitor the energy measurement value of the laser beam; The target monitoring energy value is based on the above formula and the target laser energy value E1 is substituted, as shown in the following formula: ; In the formula, E is the target monitoring energy value of the monitoring laser beam, and E1 is the target laser energy value of the main laser beam.

[0014] In step S3, the laser is adjusted based on the comparison results. Specifically, if the real-time monitored energy value is within the tolerance range, the laser maintains its current output; if it is below the lower limit of the tolerance range, the control unit instructs the laser to increase its output power; if it is above the upper limit of the tolerance range, the control unit instructs the laser to decrease its output power until the real-time monitored energy value returns to the tolerance range.

[0015] When the real-time monitoring energy value deviates from the tolerance range for 3-5 consecutive cycles, the control unit triggers the laser power adjustment.

[0016] The beneficial effects of this invention are: This invention divides the laser beam into a main laser beam for processing and a secondary laser beam for monitoring by adding a beam splitter to the laser output optical path. At the same time, it relies on a laser energy detector to monitor the energy of the secondary laser beam in real time throughout the process. This allows for the immediate capture of energy fluctuations caused by factors such as laser temperature changes, device aging, and optical lens attenuation during processing. Energy compensation is achieved by dynamically adjusting the laser output power. This fundamentally solves the problem that traditional solutions can only perform a single calibration before processing and cannot cope with energy drift during processing, ensuring that the laser energy remains stable at all times.

[0017] Furthermore, it replaces the manual shutdown and retesting, as well as the manual energy calibration required in traditional methods, eliminating the need for interruptions in the production process and achieving fully automated laser scribing. This technology reduces the proportion of non-processing time, improves overall production efficiency, and avoids errors caused by manual operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a dicing system that monitors and adjusts laser energy in real time.

[0019] In the diagram, 1. Laser, 2. Beam splitter, 3. Wafer, 4. Dicing stage, 5. Laser energy detector, 6. Control unit. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Example 1 This invention relates to a laser energy monitoring and adjustment system for dicing, primarily suitable for laser dicing of hard and brittle materials such as wafers, glass, and ceramics. It enables real-time monitoring and dynamic control of laser energy throughout the dicing process. Figure 1 As shown, the laser emitting end is equipped with a laser 1, which serves as the laser energy source for dicing. The laser beam it outputs is transmitted downwards along a preset optical path. Below the laser 1, on the laser beam transmission path, a beam splitter 2 is precisely positioned. This beam splitter is the core component for splitting the laser beam, which can stably divide the incident laser beam emitted by the laser 1 into two paths: one is the main laser beam used for dicing, which directly acts on the surface of the workpiece to be processed, completing the core dicing processes such as grooving and cutting, and is the main laser beam for workpiece processing; the other is a monitoring laser beam used for energy monitoring, whose main function is to provide feedback on the real-time output energy status of the laser 1, and it does not participate in the actual processing of the workpiece.

[0022] A laser energy detector 5 is installed on the dedicated transmission path of the monitoring laser beam. The detector's receiving end is precisely aligned with the optical path of the monitoring laser beam, and it can receive the monitoring laser beam transmitted to this location in real time, continuously and accurately collect and acquire its energy value, and convert the collected energy data into an electrical signal for output.

[0023] The laser energy detector 5 establishes a stable signal connection with the control unit 6, which can synchronously transmit the real-time collected monitoring laser beam energy signal to the control unit 6; at the same time, the control unit 6 also maintains signal communication with the laser 1, forming a signal closed loop of "monitoring-control".

[0024] In actual operation, the control unit 6 receives the monitored laser beam energy value transmitted by the laser energy detector 5 in real time and compares and analyzes the measured energy value with the preset target monitored energy value. If the measured energy value deviates from the preset energy fluctuation tolerance range, the control unit 6 will immediately generate a corresponding adjustment command and send it to the laser 1. By adjusting the output power of the laser 1, the laser energy emitted by the laser 1 will be changed until the measured energy value of the monitored laser beam returns to the tolerance range. This achieves real-time, accurate, and dynamic control of the laser energy output by the laser 1, ensuring the energy stability of the entire dicing process.

[0025] Example 2 Based on Embodiment 1 above, the control unit 6 of the present invention can be an industrial computer (IPC) or a programmable logic controller (PLC), which internally stores the dicing program and the target energy values ​​of each process recipe.

[0026] If the system is applied to a standardized, fixed-process batch dicing production line, a PLC controller can be selected as the control unit 6. The PLC controller has the advantages of strong anti-interference ability, fast response speed and high stability. It can accurately and in real time receive the energy signal transmitted by the laser energy detector 5 in the complex electromagnetic environment of the industrial site, quickly complete data comparison and send power adjustment commands to the laser 1. At the same time, it can be easily connected to the existing industrial control system of the production line to realize linkage control with motion platforms and other equipment, meeting the control requirements of production line automation and high reliability.

[0027] If the system needs to adapt to multiple process recipes, possess complex data storage and analysis capabilities, or require a visual monitoring interface, an industrial PC can be selected as the control unit. The industrial PC can have a built-in large-capacity storage module to save energy monitoring data and dicing process parameters for the entire batch of workpieces. It also supports the loading and upgrading of custom control algorithms, enabling predictive analysis of laser energy fluctuation trends. Furthermore, it can be connected to an external display terminal to form a visual monitoring platform, allowing operators to monitor the system's operating status in real time, adapting to highly flexible and information-driven processing scenarios.

[0028] Both PLC controllers and industrial control computers can realize the core function of control unit 6: receive signals from the laser energy detector to obtain real-time monitoring energy values, compare them with preset target monitoring energy values, and generate precise control signals based on the comparison results to send to laser 1, thereby completing the dynamic adjustment of laser output power.

[0029] Example 3 Based on Embodiment 2 above, in this embodiment, the beam splitter 2 serves as the core optical element for real-time laser energy monitoring in this system. It is a dedicated optical lens with an adjustable splitting ratio, allowing for flexible adaptation of the laser beam's energy distribution ratio according to the dicing process requirements of different workpieces. The beam splitter 2 employs a "transmission + reflection" beam splitting mode for the incident laser beam: the main laser beam, formed by transmission through the lens, undertakes the core function of workpiece dicing, and therefore its energy proportion is significantly higher than the other beam; the monitoring laser beam, formed by reflection through the lens, is only used for real-time laser energy monitoring and does not participate in actual processing, therefore its energy proportion is lower than the main laser beam.

[0030] Furthermore, in a preferred embodiment of the present invention, the splitting ratio of the beam splitter 2 is set to 90:10, that is, 90% of the energy of the incident laser beam will form the main laser beam through transmission, which can ensure that sufficient and stable processing energy is provided for workpiece scribing, and ensure that core processing indicators such as groove depth and width meet the standards; the remaining 10% of the energy will form a monitoring laser beam through reflection. This energy ratio can meet the requirements of the laser energy detector for accurate acquisition of energy signals, and will not cause insufficient energy of the main laser beam due to excessive shunting, thus achieving an efficient balance between processing operations and energy monitoring.

[0031] Example 4 The present invention provides a dicing method for real-time monitoring and adjustment of laser energy. Using the dicing system described in embodiments 1-3 above, before starting, the workpiece to be diced (in this embodiment, a wafer 3) is fixed on the dicing stage 4, and then the operation is performed. Specifically, the method includes the following steps: S1, before officially starting the dicing process, the entire system is specifically calibrated to establish a precise correlation between energy monitoring and actual processed energy, as follows: First, control the laser 1 to emit a laser with a fixed power. After the beam is split by the beam splitter 2, the laser energy detector 5 collects and monitors the energy measurement value of the laser beam. At the same time, the actual energy value of the main laser beam reaching the surface of the wafer 3 is obtained through a special calibration device. Based on the preset splitting ratio of beam splitter 2, a linear proportional relationship between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam on the wafer surface is established by fitting. Retrieve the process formula corresponding to the wafer dicing, and convert the target energy value of the main laser beam required in the formula into the target monitoring energy value of the monitoring laser beam according to the above linear correspondence. Finally, based on the precision requirements of wafer dicing, the fluctuation tolerance range of the monitoring laser beam energy is set, thus defining the threshold range for subsequent energy regulation.

[0032] Furthermore, the tolerance range of this embodiment is preferably ±1% of the target monitored energy value.

[0033] S2. After confirming that the wafer 3 has been securely clamped on the dicing stage 4, the laser 1 is started. The laser emits a laser beam and is split into two paths by the beam splitter 2. The main laser beam is focused by the focusing lens and projected onto the surface of the wafer 3 to form a high energy density spot to perform the dicing and grooving operation. At the same time, the laser energy detector 5 receives and measures the energy of the laser beam in real time. That is, while the main laser beam is performing the dicing action, the laser energy detector 5 receives and measures the energy of the laser beam in real time in a high-frequency acquisition mode, and synchronously converts the energy signal into an electrical signal and transmits it to the control unit 6.

[0034] S3, the control unit 6 reads the real-time monitoring energy value of the laser energy detector 5 in real time and compares it with the target monitoring energy value, and adjusts the laser 1 based on the comparison result; S4. Repeat steps S2 and S3 to complete the laser scribing operation.

[0035] Example 5 Based on the above embodiment 4, in step S3 of the dicing method for real-time monitoring and adjustment of laser energy of the present invention, the laser 1 is adjusted based on the comparison result. Specifically, if the real-time monitored energy value is within the tolerance range, the laser 1 maintains the current output. If the output power is below the lower limit of the tolerance range, it indicates that the actual processing energy of the main laser beam is insufficient. The control unit 6 will send a power increase command to the laser 1 to gradually increase its output power percentage. If the output power is below the lower limit of the tolerance range, it indicates that the actual processing energy of the main laser beam exceeds the standard. The control unit 6 will send a power decrease command to the laser 1 to gradually decrease its output power percentage. The aforementioned power adjustment will continue until the real-time energy value of the monitored laser beam returns to the tolerance range before it can be stopped.

[0036] Furthermore, the control unit 6 will only trigger power adjustment of the laser 1 if the real-time energy value of the monitored laser beam continuously deviates from the tolerance range for 3-5 consecutive acquisition cycles. This cycle threshold can filter out occasional fluctuations in a single acquisition, ensuring the effectiveness of the control command, while also ensuring that energy deviations are responded to in a timely manner, preventing excessive delays from affecting the dicing quality, thus achieving a balance between timely control and anti-interference.

[0037] Example 6 Based on Embodiment 4 above, the specific steps in Step S1 of the laser energy monitoring and adjustment method of this invention, which establish the correspondence between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam reaching the workpiece surface, involve first determining the splitting ratio k of the beam splitter 2. The splitting ratio k refers to the proportion of the energy of the monitoring laser beam emitted from the beam splitter to the total laser energy incident on the beam splitter. Then, the optical path loss coefficient θ of the main laser beam from the beam splitter to the workpiece surface is obtained through an idle calibration procedure. 主 The optical path loss coefficient θ of the laser beam from the beam splitter to the laser energy detector is monitored. 监 Based on k, θ 主 and θ 监 A linear correspondence is established between the two, as shown in the following equation: ; In the formula, The actual energy of the main laser beam reaching the workpiece surface; Monitor the energy measurement value of the laser beam; When the process formula requires the target laser energy value E1 for the main laser beam to reach the workpiece surface, substituting the above correspondence, the target monitoring energy value E of the monitoring laser beam can be obtained as follows: ; In the formula, E is the target monitoring energy value of the monitoring laser beam, and E1 is the target laser energy value of the main laser beam.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dicing system for real-time monitoring and adjustment of laser energy, characterized in that, The system includes a beam splitter (2) located below the laser (1). The beam splitter (2) is located on the laser beam path and divides the laser beam into a main laser beam for dicing operations and a monitoring laser beam for energy monitoring. A laser energy detector (5) is installed on the monitoring laser beam path. The laser energy detector (5) is connected to a control unit (6). The control unit (6) is also connected to the laser (1). The laser energy detector (5) receives the monitoring laser beam and acquires its energy value. The control unit (6) adjusts the laser energy output by the laser (1) according to the acquired energy value.

2. The dicing system for real-time monitoring and adjustment of laser energy according to claim 1, characterized in that, The control unit (6) is a PLC controller or an industrial computer.

3. The dicing system for real-time monitoring and adjustment of laser energy according to claim 1, characterized in that, The beam splitter (2) is an optical lens with an adjustable beam splitting ratio. The main laser beam is transmitted light and has a higher energy ratio than the monitoring laser beam. The monitoring laser beam is reflected light and has a lower energy ratio than the main laser beam.

4. The dicing system for real-time monitoring and adjustment of laser energy according to claim 3, characterized in that, The beam splitter (2) has a splitting ratio of 90:10, the main laser beam accounts for 90% of the energy, and the monitoring laser beam accounts for 10% of the energy.

5. A dicing method for real-time monitoring and adjustment of laser energy, characterized in that, Using any one of the dicing systems described in 1-4 above, the method includes the following steps: S1. The system is calibrated to establish the correspondence between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam reaching the workpiece surface. The target laser energy value is converted into the target monitoring energy value of the monitoring laser beam, and the energy fluctuation tolerance range is set. S2, start the laser (1), the laser emits laser light and splits it into two paths by the beam splitter (2), the main laser beam performs a slicing action, and at the same time the laser energy detector (5) receives and measures the energy of the laser beam in real time; S3, the control unit (6) reads the real-time monitoring energy value of the laser energy detector (5) in real time and compares it with the target monitoring energy value, and adjusts the laser (1) based on the comparison result; S4. Repeat steps S2 and S3 to complete the laser scribing operation.

6. The dicing method for real-time monitoring and adjustment of laser energy according to claim 5, characterized in that, In step S1, establishing the correspondence between the measured energy value of the monitoring laser beam and the actual energy of the main laser beam reaching the workpiece surface involves first determining the splitting ratio k of the beam splitter (2), and then obtaining the optical path loss coefficient θ of the main laser beam from the beam splitter to the workpiece surface through an unloaded calibration procedure. 主 The optical path loss coefficient θ of the laser beam from the beam splitter to the laser energy detector is monitored. 监 Based on k, θ 主 and θ 监 A linear correspondence is established between the two, as shown in the following equation: ； In the formula, The actual energy of the main laser beam reaching the workpiece surface; Monitor the energy measurement value of the laser beam; The target monitoring energy value E is based on the above formula and the target laser energy value E1 is substituted into it, as shown in the following formula: ； In the formula, E is the target monitoring energy value of the monitoring laser beam, and E1 is the target laser energy value of the main laser beam.

7. The dicing method for real-time monitoring and adjustment of laser energy according to claim 5, characterized in that, In step S3, the laser (1) is regulated based on the comparison results. Specifically, if the real-time monitoring energy value is within the tolerance range, the laser (1) maintains its current output; if it is below the lower limit of the tolerance range, the control unit (6) instructs the laser (1) to increase its output power; if it is above the upper limit of the tolerance range, the control unit (6) instructs the laser (1) to decrease its output power until the real-time monitoring energy value returns to the tolerance range.

8. The dicing method for real-time monitoring and adjustment of laser energy according to claim 7, characterized in that, When the real-time monitoring energy value is detected to deviate from the tolerance range for 3-5 consecutive cycles, the control unit (6) triggers the power adjustment of the laser (1).

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