Micropore processing method of packaging substrate and packaging substrate

Abstract

The embodiment of the invention provides a micropore processing method of a packaging substrate and the packaging substrate, the packaging substrate comprises a first copper layer, a dielectric layer and a second copper layer which are stacked in sequence, and the processing method comprises the following steps: removing a first copper cover on the first copper layer by using UV laser to expose the dielectric layer at the bottom of the first copper cover; the second copper cover is removed on the second copper layer through UV laser, so that the dielectric layer at the bottom of the second copper cover is exposed, and the second copper cover is right opposite to the first copper cover; removing a part of the dielectric layer at the bottom of the first copper cover by using CO2 laser to form a blind hole; and removing part of the dielectric layer at the bottom of the second copper cover by using CO2 laser until the dielectric layer is communicated with the blind hole to form a micro through hole. According to the processing method provided by the embodiment of the invention, the copper foil on the surface of the packaging substrate does not need to be etched to form a copper window, and the process steps of film pasting pretreatment, film pasting, exposure, developing etching, film stripping and the like are removed, so that the process flow of micropore processing can be simplified, the production efficiency can be improved, and the production cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of packaging substrate processing technology, and in particular to a micro-hole processing method for a packaging substrate and a packaging substrate. Background Technology

[0002] Currently, the mainstream laser drilling machine used in the industry for micro-via processing of packaging substrates is the Japanese Mitsubishi CO2 laser drilling machine. After the copper foil on the substrate surface is browned or blackened, the minimum diameter capability for direct laser drilling is 45µm. For micro-via processing with diameter requirements below 40µm, it is necessary to first etch copper windows into the copper foil on the substrate surface to expose the dielectric layer in the middle of the substrate, and then use a CO2 laser drilling machine for drilling.

[0003] This method for processing micro-through holes involves the following steps: mechanical drilling → pre-treatment before film application → film application → exposure → development and etching → film removal → CO2 laser drilling. This method is complex, costly, and inefficient, making it unsuitable for mass production. Summary of the Invention

[0004] This application provides a micro-hole processing method for a packaging substrate and a packaging substrate, which can simplify the micro-hole processing flow, reduce production costs, and improve production efficiency.

[0005] This application provides a method for microvia fabrication on a packaging substrate, the packaging substrate comprising a first copper layer, a dielectric layer, and a second copper layer stacked sequentially, the fabrication method comprising: The first copper cap is removed from the first copper layer using a UV laser to expose the dielectric layer at the bottom of the first copper cap. The second copper cap is removed from the second copper layer using a UV laser to expose the dielectric layer at the bottom of the second copper cap, which is directly opposite the first copper cap. A portion of the dielectric layer at the bottom of the first copper cap is removed using a CO2 laser to form a blind hole; A portion of the dielectric layer at the bottom of the second copper cap is removed using a CO2 laser until it connects with the blind hole to form a micro-through hole.

[0006] In some embodiments, removing the first copper cap on the first copper layer using a UV laser includes: using the center of the through hole to be processed as the center and the circumference formed by the outer periphery of the UV laser spot on the first copper layer as the first laser trajectory, and using a UV laser to circumferentially ablate the first copper layer along the first laser trajectory to remove the first copper cap. The method of removing the second copper cap on the second copper layer using UV laser lithography includes: using the center of the through hole to be processed as the center and the circumference formed by the outer periphery of the UV laser spot on the second copper layer as the second laser trajectory, and using the UV laser to perform circular ablation of the second copper layer along the second laser trajectory to remove the second copper cap.

[0007] In some embodiments, the laser parameters for using a UV laser to perform circular ablation of the first copper layer along the first laser trajectory are: 2 to 4 circular ablation cycles, 100 to 200 mm / s cutting speed, 8 to 12 uJ laser energy, and 250 kHz laser frequency. The laser parameters for using a UV laser to perform circular ablation of the second copper layer along the second laser trajectory are: 2 to 4 circular ablation cycles, 100 to 200 mm / s cutting speed, 8 to 12 uJ laser energy, and 250 kHz laser frequency.

[0008] In some embodiments, prior to removing the first copper cap from the first copper layer using a UV laser, the processing method further includes: Multiple positioning holes are machined on the packaging substrate by mechanical drilling, and the positioning holes are through holes; When removing the first copper cap from the first copper layer using a UV laser, the laser position of the first copper layer is positioned according to the plurality of positioning holes; When removing the second copper cap from the second copper layer using a UV laser, the laser position of the second copper layer is positioned according to the plurality of positioning holes.

[0009] In some embodiments, prior to removing a portion of the dielectric layer at the bottom of the first copper cap using a CO2 laser to form a blind via, the processing method further includes: Multiple annular areas are ablated on the first copper layer using a UV laser to form multiple first positioning rings; When using a CO2 laser to remove part of the dielectric layer at the bottom of the first copper cap to form a blind hole, the laser position is positioned according to the plurality of first positioning rings.

[0010] In some embodiments, prior to removing a portion of the dielectric layer at the bottom of the second copper cap using a CO2 laser, the processing method further includes: Multiple annular areas are ablated on the second copper layer using UV laser to form multiple second positioning rings; When using a CO2 laser to remove part of the dielectric layer at the bottom of the second copper cover, the laser position is positioned according to the plurality of second positioning rings.

[0011] In some embodiments, the laser parameters for removing part of the dielectric layer at the bottom of the first copper cap using a CO2 laser are: laser energy 1.5~2.5mJ, pulse duration 5~8us, and number of pulses 1~3. The laser parameters for removing part of the dielectric layer at the bottom of the second copper cap using a CO2 laser are: laser energy 1.5~2.5mJ, pulse time 5~8us, and number of pulses 1~3.

[0012] In some embodiments, when using a CO2 laser to remove a portion of the dielectric layer at the bottom of the first copper cap, the thickness of the removed dielectric layer is 50% to 60% of the total thickness of the dielectric layer.

[0013] In some embodiments, the aperture of the micro-hole is 15~40µm.

[0014] This application also provides a packaging substrate, including a first copper layer, a dielectric layer, and a second copper layer stacked sequentially. A micro-via is formed on the packaging substrate, penetrating the first copper layer, the dielectric layer, and the second copper layer. The micro-via is formed by the processing method of any of the above embodiments.

[0015] In the processing method of this application embodiment, based on the characteristics that copper foil has a high absorption rate for UV laser and glass fiber cloth (the main component of the dielectric layer of the encapsulation substrate) has a high absorption rate for CO2 laser, the first copper cover is removed from the first copper layer using UV laser, the second copper cover is removed from the second copper layer, and then a portion of the dielectric layer at the bottom of the first copper cover is removed using CO2 laser to form a blind hole. Finally, a portion of the dielectric layer at the bottom of the second copper cover is removed using CO2 laser, ultimately forming a micro-via penetrating the encapsulation substrate. This eliminates the need to etch copper foil on the surface of the encapsulation substrate to create copper windows, removing pre-treatment, film application, exposure, development etching, and film removal processes, greatly simplifying the micro-via processing flow and improving production efficiency. Furthermore, the micro-via processing method of this application embodiment does not require additional materials such as dry film, developing solution, etching solution, and film removal solution, thus significantly reducing production costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the packaging substrate according to an embodiment of this application.

[0018] Figure 2This is a schematic flowchart of a micro-hole fabrication method for a packaging substrate according to an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the packaging substrate after the first copper cap has been removed, according to an embodiment of this application.

[0020] Figure 4 This is a schematic diagram of the packaging substrate after the second copper cap has been removed, according to an embodiment of this application.

[0021] Figure 5 This is a schematic diagram of forming blind vias on the packaging substrate according to an embodiment of this application.

[0022] Figure 6 This is a schematic diagram of the packaging substrate being rotary-cut according to an embodiment of this application.

[0023] Figure 7 This is a schematic diagram showing the positioning holes fabricated on the packaging substrate according to an embodiment of this application.

[0024] Figure 8 This is a schematic diagram showing the fabrication of a positioning ring on the packaging substrate according to an embodiment of this application. Detailed Implementation

[0025] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] This application provides a packaging substrate. (See reference...) Figure 1 , Figure 1 This is a schematic diagram of the packaging substrate according to an embodiment of this application. The packaging substrate includes a first copper layer, a dielectric layer, and a second copper layer stacked sequentially. In practical applications, the first and second copper layers can be thin layers formed of copper foil, and the dielectric layer is formed by impregnating glass fiber cloth with BT resin and curing. It should be noted that copper foil has a high absorption rate for UV lasers, while glass fiber cloth has a low absorption rate for UV lasers, but a high absorption rate for CO2 lasers.

[0027] The packaging substrate has multiple through-holes with diameters ranging from 15 to 40 μm. These through-holes are very small and can therefore be called micro-vias or micro-holes. It should be noted that the mainstream laser drilling machine used in the industry for micro-via processing of packaging substrates is the Mitsubishi CO2 laser drilling machine from Japan, which has a minimum diameter capability of 45 μm for direct laser drilling of the substrate surface. Therefore, the micro-vias on the packaging substrate in this embodiment cannot be processed using the mainstream Mitsubishi CO2 laser drilling machine.

[0028] This application also provides a method for fabricating micro-holes in a packaging substrate, used to form micro-vias with a diameter of 15-40 μm on the aforementioned packaging substrate. (Reference) Figure 2 , Figure 2 This is a schematic flowchart of a micro-hole fabrication method for a packaging substrate according to an embodiment of this application. The fabrication method includes the following steps: 110. Use a UV laser to remove the first copper cap on the first copper layer to expose the dielectric layer at the bottom of the first copper cap; 120. Use a UV laser to remove the second copper cap on the second copper layer to expose the dielectric layer at the bottom of the second copper cap, with the second copper cap facing the first copper cap. 130. A portion of the dielectric layer at the bottom of the first copper cap is removed using a CO2 laser to form a blind via; 140. Use a CO2 laser to remove part of the dielectric layer at the bottom of the second copper cap until it connects with the blind hole to form a micro-through hole.

[0029] Please refer to the above. Figures 3 to 5 , Figure 3 This is a schematic diagram of the packaging substrate after the first copper cap has been removed, according to an embodiment of this application. Figure 4 This is a schematic diagram of the packaging substrate after the second copper cap has been removed, according to an embodiment of this application. Figure 5 This is a schematic diagram of forming blind vias on the packaging substrate according to an embodiment of this application.

[0030] The process begins by placing the packaging substrate on a UV laser drilling machine table. A UV laser is then used to ablate the first copper layer, removing the first copper cap and exposing the dielectric layer beneath it. Figure 3 As shown. Figure 3 In the middle, the copper foil on the upper surface of the packaging substrate refers to Figure 1 The first copper layer in the package substrate refers to the intermediate dielectric layer. Figure 1 The dielectric layer in the packaged substrate refers to the copper foil on the underside of the substrate. Figure 1 The second copper layer in the process. The first copper cap is a tiny area on the first copper layer. When using a UV laser, the first copper layer is burned through, creating a tiny pit on the surface of the packaging substrate after the first copper cap is removed. Understandably, in practical applications, the number of micro-holes that need to be processed on the packaging substrate is multiple; therefore, the operation of removing the first copper cap needs to be repeated multiple times using a UV laser to create a pit like... Figure 1 The image shows multiple pits after the first copper cap was removed.

[0031] Subsequently, the packaging substrate is flipped over and placed on the UV laser drilling machine table. The second copper layer is then ablated again using a UV laser to remove the second copper cap, exposing the dielectric layer beneath it. The second copper cap is directly opposite the first copper cap. A schematic diagram of the packaging substrate after removing the second copper cap is shown below. Figure 4 As shown. When using a UV laser, the second copper layer is burned through, creating a tiny pit on the lower surface of the packaging substrate after the second copper cap is removed. Multiple pits are formed on the lower surface. Understandably, in practical applications, multiple micro-holes need to be processed; therefore, multiple first and second copper caps are removed. Each removed second copper cap corresponds to one removed first copper cap, meaning each pit formed on the lower surface is directly opposite each pit formed on the upper surface.

[0032] Subsequently, the packaging substrate is placed on the CO2 laser drilling machine table, and the dielectric layer at the bottom of the first copper cap is ablated using a CO2 laser to remove part of the dielectric layer at the bottom of the first copper cap to form a blind via, such as... Figure 5 As shown. In practical applications, blind holes formed by CO2 laser engraving can be V-shaped.

[0033] Subsequently, the packaging substrate is flipped over and placed on the CO2 laser drilling machine table. The CO2 laser is then used again to ablate the dielectric layer at the bottom of the second copper cap, removing part of the dielectric layer until it connects with the blind via formed on the dielectric layer, thus creating a micro-via. A schematic diagram of the packaging substrate in this state is shown below. Figure 1 As shown. In practical applications, the final micro-hole can be an X-shaped through-hole.

[0034] In this embodiment, based on the high absorption rate of copper foil to UV lasers and the high absorption rate of glass fiber cloth (the main component of the dielectric layer of the encapsulation substrate) to CO2 lasers, a UV laser is first used to remove the first copper cap on the first copper layer, and a second copper cap is removed on the second copper layer. Then, a CO2 laser is used to remove part of the dielectric layer at the bottom of the first copper cap to form a blind hole, and a CO2 laser is used to remove part of the dielectric layer at the bottom of the second copper cap, ultimately forming a micro-via penetrating the encapsulation substrate. This eliminates the need to etch copper foil on the surface of the encapsulation substrate to create copper windows, removing processes such as pre-film processing, film application, exposure, development etching, and film removal, greatly simplifying the micro-via processing flow and improving production efficiency. Furthermore, the micro-via processing method of this embodiment does not require additional materials such as dry film, developing solution, etching solution, and film removal solution, thus significantly reducing production costs.

[0035] In some embodiments, when removing the first copper cover on the first copper layer using a UV laser, the method includes: using the center of the through hole to be processed as the center and the outer periphery of the UV laser spot forming a circle on the first copper layer as the first laser trajectory, and using the UV laser to perform circular ablation of the first copper layer along the first laser trajectory to remove the first copper cover.

[0036] For details, please refer to Figure 6 , Figure 6This is a schematic diagram of the encapsulation substrate being spin-cut according to an embodiment of this application. Taking a via diameter of 30µm (i.e., the diameters of the first and second copper caps to be removed are both 30µm) and a UV laser beam diameter of 15µm as an example, the first laser trajectory is defined by the center of the via diameter to be processed and the outer periphery of the UV laser spot forming a circle on the first copper layer. The resulting laser trajectory is as follows: Figure 6 As shown by the dashed circle. Then, a UV laser is used to ablate the first copper layer in a circular motion along the first laser trajectory, i.e., rotary cutting, so that the ablation area gradually increases (ultimately forming an ablation area with a diameter of 30um) and the ablation depth gradually increases, ultimately achieving the effect of removing the first copper cap.

[0037] In some embodiments, the laser parameters for using a UV laser to perform circular ablation of the first copper layer along a first laser trajectory are: 2-4 ablation cycles, a cutting speed of 100-200 mm / s, a laser energy of 8-12 uJ, and a laser frequency of 250 kHz. Using these laser parameters achieves good removal of the first copper layer while maintaining high processing efficiency.

[0038] In some embodiments, removing the second copper cap from the second copper layer using a UV laser includes: using the center of the through-hole to be processed as the center and the outer periphery of the UV laser spot forming a circle on the second copper layer as the second laser trajectory, and using the UV laser to perform circular ablation along the second laser trajectory to remove the second copper cap. It should be noted that the specific method for removing the second copper cap from the second copper layer can be the same as the specific method for removing the first copper cap from the first copper layer described above; refer to [reference needed]. Figure 6 The illustrations and descriptions in the above embodiments will not be repeated here.

[0039] In some embodiments, the laser parameters for using a UV laser to perform circular ablation of the second copper layer along a second laser trajectory are: 2-4 ablation cycles, a cutting speed of 100-200 mm / s, a laser energy of 8-12 uJ, and a laser frequency of 250 kHz. Similarly, using the above laser parameters for ablation achieves a good removal effect on the second copper layer while maintaining high processing efficiency.

[0040] In some embodiments, before removing the first copper cap from the first copper layer using a UV laser, the processing method further includes: machining a plurality of positioning holes on the packaging substrate by mechanical drilling, wherein the positioning holes are through holes. (Reference) Figure 7 , Figure 7This is a schematic diagram illustrating the fabrication of positioning holes on a packaging substrate according to an embodiment of this application. Multiple positioning holes can be fabricated on the packaging substrate using a mechanical drill, penetrating the first copper layer, the dielectric layer, and the second copper layer of the packaging substrate. For example, in one example, the positioning holes can be through-holes with a diameter of 2.0 mm, and there can be four positioning holes distributed at the four corners of the packaging substrate.

[0041] When removing the first copper cap from the first copper layer using a UV laser, the laser position on the first copper layer is determined based on the aforementioned positioning holes, and the UV laser is used for laser processing according to the determined position. Similarly, when removing the second copper cap from the second copper layer using a UV laser, the laser position on the second copper layer is determined based on the aforementioned positioning holes, and the UV laser is used for laser processing according to the determined position. It is understandable that determining the processing position based on the positioning holes ensures the accuracy of the laser processing position and improves the processing precision of the micro-holes.

[0042] In some embodiments, before using a CO2 laser to remove a portion of the dielectric layer at the bottom of the first copper cap to form a blind hole, the processing method further includes: using a UV laser to ablate multiple annular regions on the first copper layer to form multiple first positioning rings.

[0043] refer to Figure 8 , Figure 8 This is a schematic diagram illustrating the fabrication of a positioning ring on the packaging substrate according to an embodiment of this application. A UV laser is used to ablate the first copper layer along a circular path, penetrating the entire copper layer to form the first positioning ring. In practical applications, multiple ablation cycles can be performed along the circular path at different locations to form multiple first positioning rings; for example, there can be four first positioning rings distributed at the four corners of the first copper layer. In one example, the outer diameter of the first positioning ring is 500 μm, and the ring width is 15 μm (the UV laser spot diameter is 15 μm). In one example, the UV laser parameters for forming the first positioning ring are: 2-4 ablation cycles, a cutting speed of 100-200 mm / s, a laser energy of 8-12 μJ, and a laser frequency of 250 kHz.

[0044] Understandably, in practical applications, the step of forming the first positioning ring by UV laser etching of the first copper layer can be performed after removing the first copper cap on the first copper layer using UV laser etching in step 110. That is, the packaging substrate is placed on the UV laser drilling machine table, the first copper cap is removed from the first copper layer using UV laser etching first, and then multiple first positioning rings are formed on the first copper layer using UV laser etching.

[0045] Subsequently, in step 130, when using a CO2 laser to remove a portion of the dielectric layer at the bottom of the first copper cap to form a blind hole, the laser position is positioned according to the aforementioned multiple first positioning rings, and the CO2 laser is used for laser processing based on the positioned position. It is understandable that positioning the laser position according to the first positioning rings ensures the accuracy of the laser processing position and improves the processing precision of the micro-holes.

[0046] In some embodiments, before removing a portion of the dielectric layer at the bottom of the second copper cap using a CO2 laser, the processing method further includes: using a UV laser to ablate multiple annular regions on the second copper layer to form multiple second positioning rings. For example, there can be four second positioning rings, distributed at the four corners of the second copper layer. It should be noted that the specific method for forming the second positioning rings on the second copper layer can be the same as the specific method for forming the first positioning rings on the first copper layer described above; refer to [reference needed]. Figure 8 The illustrations and descriptions in the above embodiments will not be repeated here.

[0047] In one example, the outer diameter of the second positioning ring is 500 μm, and the ring width is 15 μm (the UV laser spot diameter is 15 μm). In another example, the UV laser parameters for forming the second positioning ring are: 2-4 ablation cycles, 100-200 mm / s cutting speed, 8-12 μJ laser energy, and 250 kHz laser frequency.

[0048] Understandably, in practical applications, the step of forming the second positioning ring by UV laser etching of the second copper layer can be performed after removing the second copper cap on the second copper layer using UV laser etching in step 120. That is, the packaging substrate is flipped over and placed on the UV laser drilling machine table, the second copper cap is first removed from the second copper layer using UV laser etching, and then multiple second positioning rings are formed on the second copper layer using UV laser etching.

[0049] Subsequently, in step 140, when using a CO2 laser to remove part of the dielectric layer at the bottom of the second copper cap, the laser position is located according to the aforementioned multiple second positioning rings, and the CO2 laser is used for laser processing based on the positioned position. It is understandable that positioning the laser position according to the second positioning rings ensures the accuracy of the laser processing position and improves the processing precision of the micro-holes.

[0050] In some embodiments, the laser parameters for removing a portion of the dielectric layer at the bottom of the first copper cap using a CO2 laser are: laser energy 1.5~2.5 mJ, pulse duration 5~8 μs, and number of pulses 1~3. The laser parameters for removing a portion of the dielectric layer at the bottom of the second copper cap using a CO2 laser are: laser energy 1.5~2.5 mJ, pulse duration 5~8 μs, and number of pulses 1~3. Using the above laser parameters achieves good removal of the dielectric layer while maintaining high processing efficiency.

[0051] In some embodiments, when using a CO2 laser to remove a portion of the dielectric layer at the bottom of the first copper cap, the thickness of the removed dielectric layer is 50% to 60% of the total thickness of the dielectric layer, that is, the thickness removed is at least half of the total thickness of the dielectric layer. Subsequently, when using a CO2 laser to remove a portion of the dielectric layer at the bottom of the second copper cap, the thickness of the removed dielectric layer is 40% to 50% of the total thickness of the dielectric layer, until it connects with the blind hole formed in the previous process to form a micro-through hole.

[0052] This application also provides a packaging substrate, including a first copper layer, a dielectric layer, and a second copper layer stacked sequentially. The packaging substrate has micro-vias penetrating the first copper layer, the dielectric layer, and the second copper layer, and these micro-vias are formed using the processing method of any of the above embodiments.

[0053] In the description of this application, it should be understood that terms such as “first” and “second” are used only to distinguish similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0054] The micro-hole processing method and the packaging substrate provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for fabricating micropores on a packaging substrate, characterized in that, The packaging substrate comprises a first copper layer, a dielectric layer, and a second copper layer stacked sequentially, and the processing method includes: The first copper cap is removed from the first copper layer using a UV laser to expose the dielectric layer at the bottom of the first copper cap. The second copper cap is removed from the second copper layer using a UV laser to expose the dielectric layer at the bottom of the second copper cap, which is directly opposite the first copper cap. A portion of the dielectric layer at the bottom of the first copper cap is removed using a CO2 laser to form a blind hole; A portion of the dielectric layer at the bottom of the second copper cap is removed using a CO2 laser until it connects with the blind hole to form a micro-through hole.

2. The processing method according to claim 1, characterized in that: The method of removing the first copper cover on the first copper layer using UV laser lithography includes: taking the center of the through hole to be processed as the center and the circumference formed by the outer periphery of the UV laser spot on the first copper layer as the first laser trajectory, and using the UV laser to circumferentially erode the first copper layer along the first laser trajectory to remove the first copper cover. The method of removing the second copper cap on the second copper layer using UV laser lithography includes: using the center of the through hole to be processed as the center and the circumference formed by the outer periphery of the UV laser spot on the second copper layer as the second laser trajectory, and using the UV laser to perform circular ablation of the second copper layer along the second laser trajectory to remove the second copper cap.

3. The processing method according to claim 2, characterized in that: The laser parameters for using a UV laser to perform circular ablation of the first copper layer along the first laser trajectory are: 2 to 4 circular ablation cycles, 100 to 200 mm / s cutting speed, 8 to 12 uJ laser energy, and 250 kHz laser frequency. The laser parameters for using a UV laser to perform circular ablation of the second copper layer along the second laser trajectory are: 2 to 4 circular ablation cycles, 100 to 200 mm / s cutting speed, 8 to 12 uJ laser energy, and 250 kHz laser frequency.

4. The processing method according to claim 1, characterized in that, Before removing the first copper cap from the first copper layer using a UV laser, the processing method further includes: Multiple positioning holes are machined on the packaging substrate by mechanical drilling, and the positioning holes are through holes; When removing the first copper cap from the first copper layer using a UV laser, the laser position of the first copper layer is positioned according to the plurality of positioning holes; When removing the second copper cap from the second copper layer using a UV laser, the laser position of the second copper layer is positioned according to the plurality of positioning holes.

5. The processing method according to claim 1, characterized in that, Before using a CO2 laser to remove a portion of the dielectric layer at the bottom of the first copper cap to form a blind via, the processing method further includes: Multiple annular areas are ablated on the first copper layer using a UV laser to form multiple first positioning rings; When using a CO2 laser to remove part of the dielectric layer at the bottom of the first copper cap to form a blind hole, the laser position is positioned according to the plurality of first positioning rings.

6. The processing method according to claim 1, characterized in that, Before using a CO2 laser to remove part of the dielectric layer at the bottom of the second copper cap, the processing method further includes: Multiple annular areas are ablated on the second copper layer using UV laser to form multiple second positioning rings; When using a CO2 laser to remove part of the dielectric layer at the bottom of the second copper cover, the laser position is positioned according to the plurality of second positioning rings.

7. The processing method according to any one of claims 1 to 6, characterized in that: The laser parameters for removing part of the dielectric layer at the bottom of the first copper cap using a CO2 laser are: laser energy 1.5~2.5mJ, pulse time 5~8us, and number of pulses 1~3. The laser parameters for removing part of the dielectric layer at the bottom of the second copper cap using a CO2 laser are: laser energy 1.5~2.5mJ, pulse time 5~8us, and number of pulses 1~3.

8. The processing method according to any one of claims 1 to 6, characterized in that, When using a CO2 laser to remove part of the dielectric layer at the bottom of the first copper cap, the thickness of the removed dielectric layer is 50% to 60% of the total thickness of the dielectric layer.

9. The processing method according to any one of claims 1 to 6, characterized in that, The diameter of the micro-hole is 15~40um.

10. A packaging substrate, characterized in that, The package includes a first copper layer, a dielectric layer, and a second copper layer stacked sequentially. A micro-via is formed on the package substrate, penetrating the first copper layer, the dielectric layer, and the second copper layer. The micro-via is formed by the processing method according to any one of claims 1 to 9.

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