CN106938370B - A laser processing system and method - Google Patents

Abstract

The invention discloses a laser processing system and method. The laser processing system includes: a laser device, which provides the laser required for processing; Projected onto the workpiece table; the sensor is set above the workpiece table to collect the parameter information of the workpiece material; the processor is connected to the sensor, receives and processes the parameter information collected by the sensor, and obtains the laser spot size required by the workpiece material; the controller , connected with the processor, receiving information from the processor to control the optical system. The sensor collects the parameter information of the workpiece material in real time, and calculates the required spot size through the processor, and uses the controller to control the optical system to change the laser spot size to adjust the laser pulse energy density in real time, with good real-time performance and high cutting efficiency; During the cutting process, the laser always outputs at the rated laser power, which improves the utilization rate of laser energy.

Description

A laser processing system and method

technical field

The invention relates to the field of semiconductor processing, in particular to a laser processing system and method.

Background technique

In the field of semiconductor processing, semiconductor devices are usually manufactured in batches on a wafer, and after processing, the devices on the wafer need to be separated into individual chips, so the wafer needs to be cut.

Mechanical cutting is usually used for wafer workpieces, mainly including three cutting methods: grinding wheel cutter, laser cutting and ion etching. Among them, the cutting path of the grinding wheel cutter is relatively wide, which is easy to cause edge chipping and cracks when cutting and thinning wafer workpieces. In addition, since more and more semiconductor devices use low-k dielectric materials, the ductility and low adhesion of the materials make cutting very difficult, easily causing cracks and splits in the cutting area. layer, and even wrap the blade and cause the knife to break, so the adaptability of the grinding wheel knife to cut is poor. The cost of ion etching is relatively high, and the process is relatively complicated. It is necessary to first cut the surface material to expose the substrate, and then perform deep etching with ions.

Laser cutting is to focus the laser beam on the surface or inside of the workpiece material, and the material will break itself by melting, gasification and modification after absorbing photons. When using long pulse width (such as nanosecond level) laser cutting, the workpiece material is melted and gasified, and a cutting line is formed on the material. However, due to the long pulse width laser action time, the thermal effect is more obvious, and it is easy to form heat on the surface of the material. Heat affected zone (HAZ), which causes changes in material properties and reduces material strength. Therefore, ultrafast lasers are usually chosen to cut workpiece materials.

In the field of semiconductor processing, different materials are usually used to manufacture IC devices, such as copper, low-k dielectric materials. The thickness of different materials is different, and these materials are covered on the workpiece substrate layer by layer. When cutting, these materials and the substrate need to be cut completely. Because different materials absorb laser light differently, their ablation thresholds are also different. The eclipse threshold refers to the minimum laser energy density required for the laser to act on the material to cause a phase change in the material and to remove the material. Therefore, the laser pulse energy density required to cut different materials is also different. Excessive laser energy density will be converted into heat energy, which will heat up the material and even destroy the processed IC circuit. Therefore, it is very important to choose different laser pulse energy densities to cut different material layers on the workpiece and different regions of the workpiece.

In the prior art, a method of focusing light spots with variable astigmatism formed when cutting a substrate is given. In this method, the laser beam is first expanded, and then the expanded beam is modified so that the beam is collimated along the astigmatic axis and converged along the focusing axis to form an astigmatic focused spot on the substrate surface, the spot has an elongated shape, and along the The scatter axis is the length and along said focus axis is the width, and the width is less than the length. By adjusting the size of the astigmatism focused spot, the energy density on the workpiece substrate is in an optimal state. The astigmatism focusing spot moves relative to the base of the workpiece along the length direction to form the spot ablation to achieve the cutting effect. However, this technology does not disclose how to adjust the spot size to achieve the best cutting effect, and only one method is used to adjust the laser energy density, which has great limitations.

Later, a method for laser scribing workpieces that can change the time pulse profile was proposed in the prior art. The method includes a first time pulse profile cutting a layer of the substrate using a laser sequence of the first time pulse profile and a second time pulse profile cutting a remaining portion of the workpiece using the laser sequence of the second time pulse profile. The first time pulse profile and the second time pulse profile refer to the intensity of the laser pulse changing with time to form different profile shapes, such as Gaussian time pulse profile, square time pulse profile and triangular time pulse profile. According to the specificity of the substrate material, the laser time pulse profile can be customized to achieve the best cutting effect. However, this method still has the following deficiencies: First, the utilization rate of laser energy is inevitably reduced by adjusting the time pulse profile, and a complex laser output control system is required to adjust the output light intensity over time, which is costly ; Second, this method is only applicable to nanosecond pulse lasers, and the adjustment effect for picosecond laser pulses is greatly reduced, so it cannot actually meet the actual needs.

Contents of the invention

The present invention provides a laser processing system and method to solve the above technical problems.

In order to solve the above technical problems, the technical solution of the present invention is: a laser processing system for processing the workpiece material on the workpiece table, including: a laser, which provides the laser required for processing; an optical system, which is arranged on the workpiece Above the stage, adjust the spot size of the laser, and project the adjusted laser spot onto the workpiece stage; the sensor is arranged above the workpiece stage to collect the parameter information of the workpiece material; the processor, with the The sensor is connected to receive and process the parameter information collected by the sensor to obtain the laser spot size required by the workpiece material; the controller is connected to the processor and receives the information from the processor to control the optical system to form the required of the spot size.

Further, the laser is a pulsed laser.

Further, the optical system includes a laser lens and a collimator lens arranged in sequence along the optical path, the collimator lens is connected to a motor, the motor is connected to the controller, and the motor drives the collimator lens relative to the The movement of the laser lens is described.

Further, the optical system includes a turntable mechanism, and the turntable mechanism is provided with several through holes, and diffractive optical elements are arranged in the through holes, and the shapes of the diffractive optical elements in the through holes are different.

Further, the sensor is a photodetector, which measures the reflectivity of the workpiece material.

Further, the sensor is a laser displacement sensor, which measures the thickness of the workpiece material and the remaining thickness of the material after cutting.

Further, the sensor is a high-speed camera, which measures the kerf width of the workpiece material.

The present invention also provides a laser processing method of a laser processing system, comprising the following steps:

S1: The laser emits laser light and irradiates the workpiece material on the workpiece table after passing through the optical system; the optical system forms processing spots of different sizes on the workpiece surface, thereby obtaining the laser energy density required for cutting different workpiece materials;

S2: The sensor collects parameter information of the workpiece material in real time, and sends the collected parameter information to the processor;

S3: The processor receives the parameter information, processes it, and calculates the laser spot size required for the workpiece material according to the laser pulse energy density required for cutting the workpiece material, and will include the spot size The information is sent to the controller;

S4: The controller controls the optical system to form the required spot size according to the received information of the spot size, so as to achieve the laser pulse energy density required by the workpiece material;

S5: The workpiece material moves relative to the laser spot to form a processing track, and the workpiece material is processed.

Further, in the step S2, the parameter information includes the reflectivity of the workpiece material, the thickness of the workpiece material, the remaining thickness of the material after cutting, and the kerf width of the workpiece material.

The present invention provides a laser processing system and method. The laser processing system includes: a laser, which provides the laser required for processing; The laser spot is projected onto the workpiece table; the sensor is arranged above the workpiece table to collect the parameter information of the workpiece material; the processor is connected to the sensor, receives and processes the parameter information collected by the sensor, and obtains The spot size of the laser light required by the workpiece material; the controller is connected with the processor and receives information from the processor to control the optical system. The sensor collects the parameter information of the workpiece material in real time, and calculates the required spot size through the processor, and uses the controller to control the optical system to change the laser spot size to adjust the laser pulse energy density in real time, with good real-time performance and high cutting efficiency; During the cutting process, the laser is always output at the rated laser power, and the laser energy is used for cutting to the greatest extent, and it is not limited by the laser pulse width. It has wide applicability and greatly improves the utilization rate of laser energy.

Description of drawings

Fig. 1 is a schematic structural view of embodiment 1 of the laser processing system of the present invention;

Figures 2a and 2b are the top view and front view of the workpiece in Embodiment 1 of the laser processing system of the present invention, respectively;

3 is a schematic structural view of the optical system in Embodiment 1 of the laser processing system of the present invention;

Fig. 4a is a schematic structural diagram of an optical system corresponding to a type of diffractive optical element in Embodiment 2 of the laser processing system of the present invention;

Fig. 4b is a schematic diagram of spots formed by four diffractive optical elements in Fig. 4a;

Fig. 5a is a schematic structural diagram of an optical system corresponding to another type of diffractive optical element in Embodiment 2 of the laser processing system of the present invention;

Fig. 5b is a schematic diagram of the light spots formed by the four diffractive optical elements in Fig. 5a.

As shown in the figure: 1. workpiece table; 2. workpiece material; 201. device layer; 202. workpiece substrate; 203. protective adhesive layer; 204. chip; 3. laser; 301. laser; 4. optical system; 401. Laser lens; 402, collimating lens; 403, turntable mechanism; 404a-404d, diffractive optical element; 302, 405a-405d, elliptical spot; 406a-406d, circular spot; 5, sensor; 6, processor; 7, controller.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

Example 1

As shown in Figures 1-3, a kind of laser processing system of the present invention is used for processing (that is, cutting) the workpiece material 2 on the workpiece table 1, including: a laser 3, providing laser 301 required for processing, preferably, The laser 3 is a pulsed laser, and the width of its pulse is not limited. For example, it can be a laser 3 with an ultrashort pulse width, which is beneficial to control the thermal influence in the cutting process; the optical system 4 is located above the workpiece table 1 , adjust the spot size of the laser 301, and project the adjusted spot of the laser 301 onto the workpiece table 1; the sensor 5 is arranged above the workpiece table 1, and collects the parameter information of the workpiece material 2; processing A device 6 is connected to the sensor 5 to receive and process the parameter information collected by the sensor 5 to obtain the spot size of the laser 301 required by the workpiece material 2; a controller 7 is connected to the processor 6 to receive the processing The information of the device 6 controls the optical system 4 to form the required spot size. It should be noted that, as shown in Figure 2a-2b is a schematic structural view of the workpiece material 2, including a device layer 201, a workpiece substrate 202 and a protective adhesive layer 203 from top to bottom, wherein the device layer 201 is composed of multiple layers of different materials , and several chips 204 are formed after cutting, and the protective adhesive layer 203 is pasted on the bottom surface of the workpiece substrate 202 before cutting, which can prevent the chips 204 from being scattered after cutting. The parameter information of the workpiece material 2 is collected in real time by the sensor 5, and the required spot size is calculated by the processor 6, and the laser pulse energy density is adjusted in real time by controlling the optical system 4 by the controller 7 to change the spot size of the laser 301, and the real-time performance is good. , high cutting efficiency; during the cutting process, the laser 3 always outputs at the rated laser power, maximizing the use of laser energy for cutting, and is not limited by the laser pulse width, wide applicability, greatly improving the utilization rate of laser energy .

As shown in FIG. 3 , the optical system 4 continuously or discontinuously adjusts the shape and size of the laser spot acting on the workpiece surface. The optical system 4 includes a laser lens 401 and a collimator lens 402 arranged in sequence along the optical path, the collimator lens 402 is connected to a motor (not shown in the figure), the motor is connected to the controller 7, and the The motor drives the collimator lens 402 to move relative to the laser lens 401 . Specifically, the laser light 301 is incident on the incident end face of the laser lens 401, and is projected onto the collimator lens 402 after passing through the exit end face to collimate the beam of the laser light 301. In this embodiment, in the vertical direction, that is, in the figure In the Y direction of the laser 301, the spot size of the laser 301 is stretched. In the horizontal direction, that is, the Z direction in the figure, the size of the spot remains unchanged, and finally an elliptical spot 302 is formed on the surface of the workpiece material 2, and its Y direction passes through the laser lens 401. The long axis is stretched, but the Z direction is not stretched, which is the short axis. At this time, the motor can drive the collimating lens 402 to move horizontally relative to the laser lens 401 to adjust the distance L between the laser lens 401 and the collimating lens 402 . The laser lens 401 of the optical system 4 that can realize the above-mentioned function has many kinds, for example, it can be a cylindrical lens, and it is not limited to stretching the spot size of a certain direction, and the mode of compressing the spot size can also be used; this embodiment is not limited to The spot size of only one direction can be adjusted, and two directions can be adjusted simultaneously; the shape of the laser 301 is not limited to a circle, and can be other shapes, such as a rectangle.

Preferably, the sensor 5 is a photodetector, which measures the reflectivity of the workpiece material 2 . Specifically, the processor 6 determines what kind of material is currently cutting the outermost layer through the reflectivity obtained by the sensor 5, determines the required laser pulse energy density according to the ablation threshold of the material, and calculates the required laser pulse energy density through the laser pulse energy density. Generally, the laser pulse energy density can be selected to be 4 to 10 times the ablation threshold. For example, the ablation threshold of Si under 15ps, 532nm laser pulse is 0.15J/cm ² , the single pulse energy of the laser is 10uJ, the long axis of the spot can be adjusted to 100um, and the short axis can be adjusted to 20um, then the single pulse energy density is 0.64 J/cm ² , about 4 times the ablation threshold.

The present invention also provides a laser processing method of the above-mentioned laser processing system, comprising the following steps:

S1: The laser 3 emits laser light 301, which is irradiated onto the workpiece material 2 of the workpiece table 1 after passing through the optical system 4. The laser light 301 can be a laser pulse of any width, and the optical system 4 forms processing spots of different sizes on the workpiece surface, thereby Obtain the laser energy density required for cutting different workpiece materials 2 .

S2: The sensor 5 collects the parameter information of the workpiece material 2 in real time, and sends the collected parameter information to the processor 6; the parameter information includes the reflectivity of the workpiece material 2, the thickness of the workpiece material 2 and the remaining material after cutting Thickness and kerf width of workpiece material 2.

S3: The processor 6 receives the parameter information, processes it, and calculates the spot size of the required laser 301 according to the laser pulse energy density required for cutting the workpiece material 2, and includes the information of the spot size Send it to the controller 7; when the parameter information is the reflectivity of the workpiece material 2, the processor 6 determines which material is currently cutting the outermost layer through the reflectivity, and determines the required laser pulse energy according to the ablation threshold of the material Density, usually the laser pulse energy density can be selected as 4 to 10 times the ablation threshold; when the parameter information is the thickness of the workpiece material 2 and the remaining thickness of the material after cutting, the processor 6 calculates the cutting depth of the workpiece material 2 and the The deviation of the target cutting depth, the controller 7 can calculate the required spot area according to the deviation, specifically, adjust the laser pulse energy density through the change of the cutting depth to adjust the cutting depth, wherein reducing the spot area can increase the laser energy pulse Density to obtain a greater depth of cut, increasing the spot area can reduce the laser energy pulse density to reduce the depth of cut, such as the target cutting depth of the workpiece material 2 is L, the processor 6 calculates the current cutting depth as L1, Then the deviation ΔL=L1–L, at this time, the controller 7 runs the PID control algorithm to obtain the currently required spot area, and controls it through the controller 7, so that the actual depth of cut is consistent with the target depth of cut; when the parameter information When it is the kerf width of the workpiece material 2, the processor 6 compares the kerf width with the target cutting width to obtain the difference of the cutting width, and calculates the required spot area according to the difference of the cutting width by the controller 7 , the optical system 4 is controlled to adjust the dimension of the laser 301 along the width direction of the slit, such as the minor axis dimension, so that the cutting width is the same as the target cutting width.

S4: The controller 7 controls the optical system 4 to form the required spot size according to the information of the received spot size, so as to achieve the laser pulse energy density required by the workpiece material 2, and the laser pulse energy density F required by the workpiece material 2 can be passed It is realized by adjusting the spot size, that is, the spot area S, F=P/S, and P represents the energy of the laser pulse. By adjusting the size of the light spot to achieve the laser pulse energy density required by the workpiece material 2, the laser 3 is always output at the maximum power during the cutting process, so that the laser use efficiency is maximized to achieve the fastest cutting speed and improve the work of the system efficiency. In addition, different optical systems 4 correspond to different spot shapes, and the processor 6 can calculate the corresponding spot shapes according to the specific optical system 4 .

S5: The workpiece table 1 drives the workpiece material 2 to move relative to the spot of the laser 301 to form a processing track, and process the workpiece material 2, that is, cut it to form a plurality of independent chips 204 .

In S5, as long as the relative movement of the workpiece material and the laser spot is sufficient to form a processing track, the present invention is not limited to the above-mentioned method in which the workpiece material is driven by the workpiece table to move.

Example 2

The difference from Embodiment 1 is that in Embodiment 2, the optical system 4 includes a turntable mechanism 403, and the turntable mechanism 403 is provided with a number of through holes, and the number of the through holes is 3-5. In the example, there are 4 through holes, and diffractive optical elements are arranged in the through holes, and the shapes of the diffractive optical elements in the 4 through holes are different, and the spot shape obtained by the laser 301 through different diffractive optical elements Different from the size, as shown in FIG. 4a, 404a-404d are different diffractive optical elements installed on the turntable mechanism 403. When the laser 301 is incident on the diffractive optical element, different diffractive spots 405a-405d will be formed, as shown in FIG. As shown in 4b, 405a is an elliptical spot formed by 404a with a major axis l1 and a minor axis m2, assuming that the laser pulse energy is u, and the corresponding laser pulse energy density is 4u/(π*l1*m1); 405a～405d All have different major and minor axes, so a total of 4 kinds of laser pulse energy densities can be formed. By rotating the turntable mechanism 403, different diffractive optical elements can be cut into the laser light path, which can realize the adjustment of the laser spot and obtain the required laser pulse energy density. As shown in Figure 5a, it is an optical system corresponding to another type of diffractive optical element. After the laser 301 passes through this type of diffractive optical element, a row of N circular spots with a diameter of R will be generated. As shown in Figure 5b, the spot is discretized The last advantage is to make the workpiece material 2 have a certain interval between the previous light spot and the next light spot, so that it can release stress and dissipate heat, which is beneficial to cutting. 404a-404d correspond to form 1-4 circular light spots with a diameter R shown in 406a-406d respectively, the areas of the light spots increase sequentially, and the corresponding pulse energy densities decrease sequentially. By rotating the turntable mechanism 403, different diffractive optical elements can be cut into the laser light path, which can realize the adjustment of the laser spot and obtain the required laser pulse energy density.

Example 3

Different from Embodiment 1, in this embodiment, the sensor 5 is a laser displacement sensor, which measures the thickness of the workpiece material 2 and the remaining thickness of the material after cutting, so as to obtain the cutting depth of the workpiece material 2, and the processor 6 Adjust the laser pulse energy density according to the change of cutting depth to adjust the cutting depth, among which reducing the spot area can increase the laser energy pulse density to obtain a greater depth of cut, increasing the spot area can reduce the laser energy pulse density to reduce the cutting depth , if the target cutting depth of the workpiece material 2 is L, and the processor 6 calculates the current cutting depth as L1, then the deviation ΔL=L1–L, at this time, the controller 7 runs the PID control algorithm to obtain the current required spot The area is controlled by the controller 7 so that the actual depth of cut is consistent with the target depth of cut, and the spot area is continuously adjusted by this method to achieve the best cutting effect.

Example 4

The difference from Embodiment 1 is that in this embodiment, the sensor 5 is a high-speed camera that measures the kerf width of the workpiece material, and the processor 6 compares the kerf width with the target cutting width to obtain the difference in cutting width, And calculate the required spot area according to the difference of the cutting width by the controller 7, control the optical system 4 to adjust the size of the laser 301 along the width direction of the slit, such as the minor axis size, so that the cutting width is equal to the target cutting width Similarly, this method can also be used to continuously adjust the spot area for multiple times to achieve the best cutting effect.

In summary, the present invention provides a laser processing system and method. The laser processing system is used to process the workpiece material 2 on the workpiece table 1, including: a laser 3, which provides a laser 301 required for processing; an optical system 4 , arranged above the workpiece table 1, adjusting the spot size of the laser 301, and projecting the adjusted spot of the laser 301 onto the workpiece table 1; the sensor 5, arranged above the workpiece table 1, collecting The parameter information of the workpiece material 2; the processor 6 is connected with the sensor 5, receives and processes the parameter information collected by the sensor 5, and obtains the spot size of the laser 301 required by the workpiece material 2; the controller 7 is connected with the sensor 5 connected to the processor 6, receiving information from the processor 6 to control the optical system 4. The parameter information of the workpiece material 2 is collected in real time by the sensor 5, and the required spot size is calculated by the processor 6, and the laser pulse energy density is adjusted in real time by controlling the optical system 4 by the controller 7 to change the size of the laser spot 4, and the real-time performance is good. High cutting efficiency; during the cutting process, the laser 3 always outputs at the rated laser power to maximize the use of laser energy for cutting, and is not limited by the laser pulse width, which has wide applicability and greatly improves the utilization rate of laser energy.

Although the embodiments of the present invention have been described in the specification, these embodiments are only used as hints and should not limit the protection scope of the present invention. Various omissions, substitutions and changes within the scope not departing from the gist of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. A laser machining system for machining a workpiece material on a workpiece table, comprising: a laser for providing laser required by processing; the optical system is arranged above the workpiece platform, adjusts the spot size of the laser and projects the adjusted laser spot onto the workpiece platform; the sensor is arranged above the workpiece table and used for acquiring parameter information of the workpiece material; the processor is connected with the sensor, receives and processes parameter information acquired by the sensor, determines which material is the most surface layer of the current cutting according to the reflectivity when the parameter information is the reflectivity of a workpiece material, determines the required laser pulse energy density according to the ablation threshold of the material, calculates the cutting depth of the workpiece material and the deviation from the target cutting depth when the parameter information is the thickness of the workpiece material and the residual thickness of the cut material, and compares the cutting width with the target cutting width when the parameter information is the cutting width of the workpiece material to obtain the cutting width difference value and obtain the laser spot area required by the workpiece material; the controller is connected with the processor and receives the information of the processor to control the motor to move to form the required light spot size; the cutting depth is adjusted by adjusting the laser pulse energy density through the change of the cutting depth, wherein the spot area is reduced to increase the laser energy pulse density so as to obtain larger cutting depth, the spot area is increased to reduce the laser energy pulse density so as to reduce the cutting depth, the processor calculates the current cutting depth, the deviation is the difference between the current cutting depth and the target cutting depth, at the moment, the controller runs a PID control algorithm to obtain the currently required spot area, and the controller controls the current cutting depth to be consistent with the target cutting depth.

2. The laser machining system of claim 1, wherein the laser is a pulsed laser.

3. The laser processing system of claim 1, wherein the optical system comprises a laser lens and a collimating lens sequentially arranged along a light path, the collimating lens is connected to a motor, the motor is connected to the controller, and the motor drives the collimating lens to move relative to the laser lens.

4. The laser processing system of claim 1, wherein the optical system comprises a turntable mechanism, the turntable mechanism is provided with a plurality of through holes, the through holes are provided with diffractive optical elements, and the diffractive optical elements in the through holes have different shapes.

5. The laser machining system of claim 1, wherein the sensor is a photodetector.

6. The laser machining system of claim 1, wherein the sensor is a laser displacement sensor.

7. The laser machining system of claim 1, wherein the sensor is a high-speed camera.

8. A laser machining method of a laser machining system, comprising the steps of:

s1: the laser emits laser, and the laser irradiates a workpiece on the workpiece table after passing through the optical system; the optical system forms processing light spots with different sizes on the surface of the workpiece, so that laser energy densities required by cutting different workpiece materials are obtained;

s2: the sensor collects the parameter information of the workpiece material in real time and sends the collected parameter information to the processor;

s3: the processor receives the parameter information, processes the parameter information, calculates the spot size of laser required by the workpiece material according to the laser pulse energy density required by cutting the workpiece material, or calculates the spot area of the laser required by the workpiece material according to the cutting depth deviation or the cutting width difference required by cutting the workpiece material, and sends the information including the spot area to the controller, when the parameter information is the reflectivity of the workpiece material, the processor determines which material is the most surface layer to be cut currently according to the reflectivity, determines the required laser pulse energy density according to the ablation threshold value of the material, when the parameter information is the thickness of the workpiece material and the residual thickness of the cut material, the processor calculates the cutting depth of the workpiece material and the deviation from the target cutting depth, and when the parameter information is the cutting seam width of the workpiece material, the processor compares the kerf width with a target cutting width to obtain a cutting width difference value;

adjusting the laser pulse energy density through the change of the cutting depth to adjust the cutting depth, wherein the spot area is reduced to increase the laser energy pulse density to obtain larger cutting depth, the spot area is increased to decrease the laser energy pulse density to reduce the cutting depth, and the processor calculates the current cutting depth, wherein the deviation is the difference between the current cutting depth and the target cutting depth;

s4: the controller controls the optical system in real time according to the information of the received light spot area to form a required light spot size so as to achieve the laser pulse energy density, the target cutting depth or the target cutting width required by the workpiece material, at the moment, the controller runs a PID control algorithm to obtain the currently required light spot area, and the controller controls the light spot area to enable the actual cutting depth to be consistent with the target cutting depth;

s5: and the workpiece material and the laser spot move relatively to form a processing track to process the workpiece material.

9. The laser machining method of the laser machining system according to claim 8, wherein the parameter information includes reflectivity of the workpiece material, thickness of the workpiece material and remaining thickness of the cut material, and kerf width of the workpiece material in step S2.