Alignment target spot processing method of substrate, embedded packaging substrate and product

Abstract

The invention discloses an alignment target spot processing method of a substrate, an embedded packaging substrate and a product, and relates to the technical field of substrate manufacturing, the method comprises the following steps: processing a first negative pad for a preset target spot on the upper surface of an inner-layer core plate, and processing a second negative pad capable of covering the first negative pad on the lower surface of the inner-layer core plate, and depth-controlled drilling is carried out from one surface of the semi-finished substrate according to the coverage range of the second negative pad, and laser ablation is carried out on the material in the range of the first negative pad on the basis of depth-controlled drilling processing, so that a hole with the minimum cross section as large as the first negative pad is finally processed, and the hole is used as a preset target spot. Therefore, the preset target points applied in different processing stages can display the horizontal position of the first negative bonding pad on the upper surface of the inner core plate, alignment is implemented based on the marks on the same plate surface, the influence of layer deviation of different plate surfaces on alignment precision can be effectively reduced, the utilization rate of the plate is improved, and the production efficiency is improved. Therefore, the processing cost of the embedded packaging product is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of substrate manufacturing, and in particular to a substrate alignment target processing method, an embedded packaging substrate and a product. Background Art

[0002] Embedded packaging refers to a substrate manufacturing process in which components (such as chips, resistors, and capacitors) are directly embedded within the substrate. When components are embedded within the substrate, blind vias are fabricated on the fan-out surface of the components to provide connectivity between the components and other circuit layers.

[0003] Currently, traditional substrate manufacturing processes require screening for layer deviation before device packaging. For example, boards with poor alignment on both sides of the frame layer are discarded, and only those with a misalignment of less than 10μm are retained. This ensures accurate alignment of the board for embedded devices, minimizing the impact of layer deviation on embedded device packaging. However, due to fluctuations in the performance of target exposure equipment, typically only approximately 50% of the frame layer can be retained after layer deviation screening, increasing the processing cost of embedded package products. Summary of the Invention

[0004] Based on this, it is necessary to provide a substrate alignment target processing method, an embedded packaging substrate and a product to address the above technical problems, so as to reduce the impact of layer deviation on the alignment accuracy of the device packaging process and reduce the manufacturing cost of the embedded packaging product.

[0005] In a first aspect, a method for processing a target alignment point of a substrate is provided, the method comprising: performing graphic production on the upper surface of an inner core board to process a first negative pad at a preset target position, the preset target comprising a first alignment target used when embedding a device and a second alignment target used when processing a device fan-out blind hole; performing graphic production on the lower surface of the inner core board to process a second negative pad at the preset target position, the second negative pad being able to cover the first negative pad; drilling from the first outer surface closest to the lower surface of a semi-finished substrate, and performing controlled depth drilling on the material within the coverage of the second negative pad, wherein the semi-finished substrate is a plate material processed from the inner core board; the depth of the controlled depth drilling does not exceed the distance between the first outer surface and the upper surface; after controlled depth drilling, performing laser ablation on the material within the coverage of the first negative pad in the semi-finished substrate to process a hole with a minimum cross-section the same size as the first negative pad, as the preset target point.

[0006] In an embodiment of the present application, after the controlled depth drilling, the material within the coverage area of the first negative pad in the semi-finished substrate is laser ablated to process a hole with a minimum cross-section that is the same size as the first negative pad, including: starting from the second outer surface closest to the upper surface on the semi-finished substrate, laser ablation is performed on the material within the coverage area of the first negative pad until the ablated laser hole is connected to the drilled hole obtained by the controlled depth drilling.

[0007] In an embodiment of the present application, if the depth-controlled drilling stops when it contacts the upper surface, then after the depth-controlled drilling, the material within the coverage area of the first negative pad in the semi-finished substrate is laser ablated to process a hole with a minimum cross-section that is the same size as the first negative pad, including: emitting a laser beam from the first outer surface, laser ablating the material within the coverage area of the first negative pad, so as to deepen the drilled hole obtained by the depth-controlled drilling.

[0008] In an embodiment of the present application, during the process of processing the second alignment target, before drilling from the first outer surface closest to the lower surface on the semi-finished substrate and performing controlled depth drilling on the material within the coverage area of the second negative pad, the method also includes: grabbing the first alignment target processed on the frame layer; embedding the device into the frame layer according to the positioning of the first alignment target; and pressing the semi-cured sheet and the conductive layer on both sides of the frame layer after the device is embedded to obtain a device board, which is a kind of semi-finished substrate.

[0009] In an embodiment of the present application, the method further includes: pasting a dry film on the solder surface of the device board on which the second alignment target is processed; grabbing the second alignment target on the device board; and processing a blind hole window pattern on the device board after pasting the dry film according to the positioning of the second alignment target.

[0010] In an embodiment of the present application, the processing depth of the depth-controlled drilling is greater than the distance between the first outer surface and the lower surface.

[0011] In an embodiment of the present application, the first alignment target includes: a laser shape alignment target for device placement groove cutting and a patch alignment target for device patching.

[0012] In a second aspect, an embedded packaging substrate is provided, wherein the embedded packaging substrate includes a preset target point processed by the substrate alignment target point processing method according to any embodiment of the first aspect.

[0013] In a third aspect, an embedded packaging product is proposed, comprising the embedded packaging substrate described in the second aspect.

[0014] In any of the above-mentioned solutions, a first negative pad is machined on the upper surface of the inner core board through patterning to form a first alignment target for embedding a device and a second alignment target for fanning out a blind hole. A second negative pad that covers the first negative pad is machined on the lower surface of the inner core board. Controlled depth drilling is performed from one side of the semi-finished substrate according to the coverage of the second negative pad, thereby reducing the dielectric thickness during laser drilling. Since the surface area of the second negative pad is larger than that of the first negative pad, even if the upper and lower surfaces of the inner core board deviate during the processing of the semi-finished substrate, there is still redundant space for the second negative pad to completely cover the first negative pad. As a result, the cross-section of the drilled hole obtained by the controlled depth drilling process can completely cover the area requiring laser ablation, thereby reducing the dielectric thickness during laser drilling. During laser drilling, laser ablation is performed only on the material within the range of the first negative pad based on the controlled depth drilling process, so that a hole with a minimum cross-section equal to that of the first negative pad is finally machined as the preset target. In this way, the preset targets used in different processing stages can all show the horizontal position of the first negative pad on the upper surface of the inner core board. Alignment based on the marks on the same board surface can effectively reduce the impact of layer deviation on the alignment accuracy of different board surfaces, thereby ensuring the alignment accuracy of the device embedded packaging process. This method no longer requires fine layer deviation screening of the board, can improve the utilization rate of the board, and thus reduce the processing cost of embedded packaging products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 This is a flow chart of a method for processing a target point on a substrate according to an exemplary embodiment of the present application; Figure 2 This is a cross-sectional view of an inner core board after the inner layer pattern is produced according to an exemplary embodiment of the present application; Figure 3 An exemplary embodiment of the present application shows a frame layer plate processed to obtain a first alignment target point; Figure 4 A cross-sectional view of another frame layer plate processed to form a first alignment target point is shown as an exemplary embodiment of the present application; Figure 5 A cross-sectional view of a device board after processing a second alignment target point is shown for an exemplary embodiment of the present application; Figure 6A cross-sectional view of another device board after processing a second alignment target point is shown as an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0018] It should be understood that the embodiments set forth below represent the necessary information to enable those skilled in the art to implement the embodiments and to illustrate the best mode of implementing the embodiments. After reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0019] It should also be understood that the terms "upper", "lower", "left", "right", "front", "back", "bottom", "middle", "top", etc. may be used in this document to describe various elements, and the indicated orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, so these elements should not be restricted by these terms.

[0020] It is further understood that the terms “comprises” and “includes” when used herein specify the presence of stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0022] The substrate alignment target processing method proposed in the embodiment of the present application can be applied to the production process of the embedded packaging substrate to mark alignment targets in the substrate that are not affected by layer deviation, and use these targets to achieve the alignment requirements of different processing stages, for example, to achieve the alignment requirements during the device embedding process, the alignment requirements during the device fan-out blind hole production process, etc., thereby achieving high-precision alignment in different processing stages during the device embedding packaging process.

[0023] Figure 1 The flowchart of a target alignment processing method for a substrate is shown as an exemplary embodiment of the present application.

[0024] like Figure 1 As shown, the alignment target processing method may include the following steps: S101, patterning is performed on the upper surface of the inner core board to process a first negative pad at a preset target position, wherein the preset target includes a first alignment target used when embedding the device and a second alignment target used when processing the device fan-out blind hole.

[0025] For example, this application targets the targets used in different processing stages / processes during the embedded package substrate manufacturing process, and processes the corresponding negative pads on the surface of the inner core board. For example, the preset targets may include, but are not limited to, a first alignment target used when embedding a device and a second alignment target used when processing the device fan-out blind via.

[0026] The first alignment target used when embedding a component may include, but is not limited to, a laser contour alignment target used for slotting the component embedding groove. For example, during the slotting process, the laser contour alignment target can be used to locate the slotting position, and then a slot for placing the component can be machined into the plate through laser contour machining.

[0027] The first alignment target used when embedding a device can also include a placement target for the device. For example, during the placement process, the placement target can be used to locate the placement position of the device in the slot, and then the device can be placed in the corresponding position by the placement machine.

[0028] The second alignment target used in device fan-out blind hole processing refers to: an alignment target used when making a fan-out blind hole for a device embedded in a substrate.

[0029] After the device is embedded in the substrate, the conductive terminals of the device (e.g., pads on the chip) need to be distributed in a more reasonable manner to different locations of the package through structures such as lines and vias on the package substrate to connect to external circuit boards or other devices. The device fan-out blind vias in this application can be understood as the via structures here. For example, after the device is embedded and before the device fan-out blind vias are made, a second alignment target can be used to locate the drilling area to make the device fan-out blind vias in the drilling area.

[0030] In one example, the inner core board may be a double-sided copper clad laminate. For example, a double-sided copper clad laminate is obtained by laminating copper foils on both sides of a prepreg.

[0031] A dry film is applied to the upper and lower surfaces of the double-sided copper clad laminate, wherein the dry film may comprise a photosensitive material and a plastic film. The laminate is then exposed, developed, etched, and stripped to produce inner layer patterns on the upper and lower surfaces.

[0032] It should be noted that the upper surface where the first negative pad is located and the lower surface where the second negative pad is located in this application are merely exemplary descriptions for ease of distinction and are not intended to limit the surfaces on which the first and second negative pads are located. For example, the first negative pad can be located on the weld surface or the base surface of the inner core board, and the second negative pad can be located on the base surface or the weld surface of the inner core board. The base surface and the weld surface are two opposing surfaces on the inner core board.

[0033] S102, patterning is performed on the lower surface of the inner core board to form a second negative pad at a preset target point, wherein the surface area of the second negative pad is greater than that of the first negative pad.

[0034] Exemplarily, both the second negative pad and the first negative pad can be manufactured according to the position of the preset target point. For example, the center position of the preset target point is used as the center point of the negative pad, and the first negative pad is manufactured on the upper surface and the second negative pad is manufactured on the lower surface.

[0035] The second negative pad can completely cover the first negative pad, and the surface area of the second negative pad is greater than the surface area of the first negative pad.

[0036] For example, the first negative pad is circular, the second negative pad is square, and the inscribed circle of the square is the same size as the first negative pad.

[0037] S103, drilling from the first outer surface closest to the lower surface of the semi-finished substrate to perform controlled depth drilling on the material within the coverage area of the second negative pad, wherein the semi-finished substrate is a plate material processed from the inner core plate; the depth of the controlled depth drilling does not exceed the distance between the first outer surface and the upper surface.

[0038] For example, after the inner core board pattern is completed, the inner core board needs to undergo multiple processing steps before the alignment process using preset targets is implemented. For the convenience of description, this application refers to the boards in this process as semi-finished substrates.

[0039] In one example, if the inner core board is a double-sided copper-clad laminate, after patterning the upper surface (i.e., one copper side of the double-sided copper-clad laminate) and the lower surface (i.e., the other copper side of the double-sided copper-clad laminate) of the inner core board, the patterned copper surface of the inner core board is browned. Prepreg is then laminated to both sides of the browned inner core board, and the laminated board serves as a frame laminate. This frame laminate can be used as a semi-finished substrate.

[0040] In one example, steps S103-S104 are performed on the frame laminate obtained by the above process to process a first alignment target on the frame laminate. Then, the laser shape alignment target for the device embedding groove processed on the frame laminate is grabbed, and the laser shape alignment target is used to locate the groove area corresponding to the device embedding groove. Then, the area is laser grooved. After the groove is completed, the patch alignment target for the device patch processed on the frame laminate is grabbed, and the patch alignment target is used to locate the patch position of the device in the device embedding groove. The device is placed at the patch position using a patch machine, thereby embedding the device into the frame laminate. After the device is embedded, the semi-cured sheet and the conductive layer are pressed together on the upper and lower surfaces of the frame laminate to finally obtain a device board, which can also be used as a semi-finished substrate.

[0041] In one example, steps S103 - S104 may be performed on the device board to form a second alignment target on the device board.

[0042] In embodiments of the present application, prior to using the preset target, controlled depth drilling and laser drilling can be performed on the semi-finished substrate produced in the current process flow to produce the desired preset target. For example, before performing the slotting process for embedding device holes, controlled depth drilling and laser drilling can be performed on the frame laminate. During controlled depth drilling, the drill begins at the outer surface of the frame laminate closest to the lower surface of the inner core laminate (this outer surface is described as the first outer surface for ease of distinction), and controlled depth drilling is performed on the material within the coverage area of the second negative pad.

[0043] The depth of the controlled depth drilling does not exceed the distance between the first outer surface and the upper surface of the inner core panel. That is, the controlled depth drilling begins at the first outer surface and stops before reaching the upper surface. For example, the controlled depth drilling stop position may be between the upper and lower surfaces of the inner core panel.

[0044] The laser drilling process may be described in the embodiment under step S104.

[0045] S104, after controlled depth drilling, laser ablation is performed on the material within the coverage area of the first negative pad in the semi-finished substrate to machine a hole with a minimum cross-section that is the same size as the first negative pad, which serves as a preset target point.

[0046] For example, after controlled depth drilling, the material within the coverage area of the first negative pad in the frame layer is laser ablated, and the hole formed by the laser ablation is connected to the drilled hole obtained by the controlled depth drilling process to form a hole with a minimum cross-section that is the same size as the first negative pad, thereby processing a first alignment target on the frame layer so that the subsequent process can use the first alignment target to locate the slot position of the device embedded in the slot hole and the position of the device patch.

[0047] In summary, the target processing method for substrates proposed in the present application processes a first negative pad corresponding to a first target used for embedding a device and a second target used for fanning out a blind hole of the device on the upper surface of the inner core board through graphic production, and processes a second negative pad that can cover the first negative pad on the lower surface of the inner core board, and performs controlled depth drilling from one side of the semi-finished substrate according to the coverage range of the second negative pad, thereby reducing the dielectric thickness during laser drilling. Moreover, since the surface area of the second negative pad is larger than that of the first negative pad, even if the upper and lower surfaces of the inner core board are deviated during the processing of the semi-finished substrate, there is redundant space for the second negative pad to completely cover the first negative pad, so that the cross section of the drilled hole obtained by the controlled depth drilling can completely cover the area that needs to be laser ablated, thereby reducing the dielectric thickness during laser drilling. During laser drilling, the material within the range of the first negative pad is laser ablated only on the basis of the controlled depth drilling process, so as to finally process a hole with a minimum cross section the same size as the first negative pad as the preset target. In this way, the preset targets used in different processing stages can all show the horizontal position of the first negative pad on the upper surface of the inner core board. Alignment based on the marks on the same board surface can effectively reduce the impact of layer deviation on the alignment accuracy of different board surfaces, thereby ensuring the alignment accuracy of the device embedded packaging process. This method no longer requires fine layer deviation screening of the board, can improve the utilization rate of the board, and thus reduce the processing cost of embedded packaging products.

[0048] In the above step S104, “after controlled depth drilling, laser ablation of the material within the coverage area of the first negative pad in the semi-finished substrate is performed to form a hole having a minimum cross-section that is the same size as the first negative pad” may include at least the following two implementations: In one embodiment, laser ablation can be performed on the material within the coverage area of the first negative pad, starting from the other outer surface of the semi-finished substrate closest to the upper surface of the inner core (i.e., the outer surface opposite the first outer surface, referred to as the second outer surface for ease of description) until the ablated laser hole connects with the drilled hole obtained through the depth-controlled drilling process. As can be seen from the above description, the diameter of the drilled hole obtained through the depth-controlled drilling process is larger than the diameter of the laser hole. Once the laser hole and the drilled hole obtained through the depth-controlled drilling process are connected through laser ablation, a target hole is obtained (for ease of description, the connected hole is referred to as the target hole). The minimum cross-section of the target hole is the same size as the first negative pad, meaning that the shape of the first negative pad is visible through the hole. At different processing stages, regardless of which side of the sheet is being processed, the target hole can be scanned to locate the position of the first negative pad on the board surface. In other words, different first negative pads can be used for alignment at different stages, thus minimizing the impact of layer deviation on alignment accuracy that may occur during different processing stages.

[0049] Since the target hole processed in this way passes through the plate, the target hole can be used as a positioning target when processing either the front or back side of the plate.

[0050] In another embodiment, if the depth-controlled drilling stops when it contacts the upper surface of the inner core board, then after the depth-controlled drilling is completed, the first negative pad will appear in the drill hole obtained by the depth-controlled drilling. In this case, a laser beam can be emitted from the first outer surface, and the laser beam passes through the drill hole obtained by the depth-controlled drilling to perform laser ablation on the material within the coverage range of the first negative pad to deepen the drill hole obtained by the depth-controlled drilling, thereby processing a hole with a minimum cross-section that is the same size as the first negative pad. For the convenience of description, it is expressed as a target hole.

[0051] In this way, there is no need to use a laser to ablate all the materials within the coverage area of the first negative pad in order to achieve the purpose of connecting the laser hole and the drilled hole obtained by the depth-controlled drilling process. Instead, it is only necessary to emit a laser beam to the drilled hole obtained by the depth-controlled drilling process to ablate the material within the coverage area of the first negative pad at the bottom of the drilled hole to a certain depth.

[0052] This method can shorten the time consumption of laser ablation and reduce the laser energy consumption. The target hole processed by this method can be used as the alignment target point when processing the first outer surface.

[0053] In one example, the first outer surface can be depth-controlled drilled and the second outer surface can be laser ablated to produce a first alignment target; either the first outer surface or the second outer surface can be depth-controlled drilled and laser ablated in sequence to produce a second alignment target.

[0054] The above two drilling methods can be combined arbitrarily, and this application does not impose any restrictions.

[0055] In some embodiments, after the second alignment target is processed, the device fan-out blind hole processing can be performed using the second alignment target. For example, the following steps can be included: A dry film is pasted on the soldering surface of the device board on which the second alignment target is processed; the second alignment target is grasped on the device board; and a blind hole window pattern is processed on the device board after the dry film is pasted using the positioning of the second alignment target.

[0056] In this embodiment, since the second alignment target can show the position of the target on the upper surface of the inner core board (because each target hole processed in this application uses the size of the first negative pad as the size of the minimum cross-section, when grabbing the target, the position of the figure represented by the minimum cross-section of the target hole on the upper surface of the inner core board can be obtained by scanning the target hole), and the device is also aligned with reference to the position of the first alignment target on the inner core board when embedded, even if the upper and lower surfaces of the inner chip in the device board have layer deviation after experiencing high temperature and other processing environments, it will not affect the alignment accuracy of the device embedding packaging process, so that fan-out blind holes can be accurately produced for the embedded device.

[0057] For ease of understanding, combined Figure 2-Figure 6 The target point alignment processing method of the substrate proposed in the embodiment of the present application is fully described. The method can be applied to the manufacturing process of the embedded package substrate: Step 1: Use a double-sided copper-clad laminate as the inner core board. The copper foils on the front and back of the double-sided copper-clad laminate are named the base side and the solder side, respectively. First, apply dry film to both sides of the double-sided copper-clad laminate. Then, the laminate is exposed, developed, etched, and stripped to obtain the inner layer patterns of the base side and the solder side.

[0058] Among them, when making the graphics, a 1.0mm circular negative pad is processed on the element surface, and a common 1.5mm square negative pad is added on the welding surface. Figure 2 This is a cross-sectional view of the inner core board after the inner layer pattern is produced. Figure 2 The L5 layer is the copper layer on the upper surface, and the L6 layer is the copper layer on the lower surface.

[0059] It should be noted that the description of the shape and size of the negative pad here is only for illustrative purposes and is not intended to be limiting.

[0060] Step 2: Brown the upper and lower surfaces of the inner core board after patterning to increase the roughness of the copper surface. PP is then laminated on the upper and lower surfaces after browning to obtain a frame layer. This frame layer can be used as a carrier for the device.

[0061] Step 3: Mechanically and laser-process the frame layer to expose the first negative pad corresponding to the first alignment target on the inner layer pattern. The specific process is as follows: Use a depth control drill on the frame layer to control the depth from the first outer surface closest to the inner pattern of the weld surface (for example, from Figure 3 The depth control starts from the D7 layer and stops when drilling down to the L6 and L5 layers, so as to reduce the processing thickness of the subsequent process. Figure 3 This is a cross-sectional view of the frame layer after processing the first alignment target. Figure 3 D4 in the figure represents PP laminated on the L5 layer, and D7 represents PP laminated on the L6 layer.

[0062] Laser ablation is performed on the second outer surface closest to the inner layer pattern of the element surface to ablate the material within the coverage area of the first negative pad, and the laser hole obtained by laser ablation is connected to the drill hole obtained by depth-controlled drilling. Figure 3 The D4 surface shown was laser ablated.

[0063] In addition, as another implementation method, Figure 4 As shown, a light spot larger than the first negative pad size can be used to perform laser ablation on the D4 layer. After exposing the copper layer of L5, a light spot with the same size as the first negative pad size can be used to ablate the residual medium between the L5 and L6 layers. Figure 4 A cross-sectional view of another frame layer plate for processing the first alignment target.

[0064] Step 4: Use the laser shape alignment target in the processed first alignment target to locate the slot position on the element surface of the frame layer to process the device embedded slot, and then use the patch alignment target to locate the placement position of the device in the slot, stick a protective layer on the welding surface of the frame layer, and then place the device from the element surface of the frame layer into the device embedded slot.

[0065] Step 5: Press PP on both sides of the frame layer after the device is embedded to obtain the device board. The specific process is as follows: PP and copper layers are laminated on the element surface of the frame layer in sequence to obtain a device-like board; The protective layer attached to the soldering surface of the device-like board is removed, and then the PP and copper layers are pressed in sequence on the soldering surface of the device-like board to obtain the device board.

[0066] Step 6: Mechanically and laser-process the device board to expose the first negative pad corresponding to the second alignment target on the inner layer pattern. The specific process is as follows: Controlled depth drilling is performed from the outer surface of the device board close to the inner layer pattern of the solder surface to reduce the thickness of the subsequent process. Figure 5 As shown, deep drilling starts from the L8 surface and stops between the L6 and L5 layers. Figure 5 In the figure, D7 is the entire PP layer pressed on the inner core plate welding surface (L6), L8 is the copper layer pressed on D7, D4 is the entire PP layer pressed on the inner core plate element surface (L5), and L3 is the copper layer pressed on D4.

[0067] Then, laser ablation is performed from the outer surface of the device board close to the inner layer pattern of the element surface. If the spot size used when starting laser ablation is larger than the size of the first negative pad, the ablation is stopped when it reaches the L5 layer, and a spot with the same size as the first negative pad is used to ablate the medium under the first negative pad. Figure 5 This is a cross-sectional view of the device board after the second alignment target is processed.

[0068] As another possible implementation method, Figure 6 As shown, during depth-controlled drilling, the depth can be controlled starting from the L8 layer and stopped when it contacts the L5 layer. Then, the dielectric on the first negative pad is ablated in the drill hole obtained by the depth-controlled drilling.

[0069] Step 7: Paste dry film on the device board with the second alignment target processed, grab the second alignment target to locate the processing area of the device fan-out blind hole, and process the device board with the dry film pasted through processes such as exposure, development, etching, and film stripping to process the blind hole window pattern in the processing area of the device fan-out blind hole.

[0070] Step 8: Use a laser drill to ablate the window position on the device board with the blind hole window pattern to expose the pad on the device.

[0071] It should be noted that step 8 may include multiple post-processes, which will not be described here in detail.

[0072] above Figure 2-Figure 6 The structures shown are all exemplary descriptions and are not intended to limit the present application.

[0073] The target point processing method provided by the present invention uses the first negative pad on the same layer as the benchmark for the target points involved in the slotting, patching, fan-out blind hole production, etc., and can achieve high-precision alignment between different layers in the traditional circuit board processing technology, and can completely avoid the influence of layer drop on the board alignment. It can be used not only for packaging circuit boards but also for the processing of high-density multi-layer HDI circuit boards.

[0074] The present application also proposes an embedded packaging substrate, which includes a preset target point processed by the substrate alignment target point processing method described in any of the above embodiments.

[0075] The present application also proposes an embedded package product, which includes the embedded package substrate provided by the above embodiment.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for processing a target point of a substrate, characterized in that: The method comprises: Performing patterning on the upper surface of the inner core board to form a first negative pad at a preset target point, wherein the preset target point includes a first alignment target point used when embedding the device and a second alignment target point used when processing the device fan-out blind hole; Performing patterning on the lower surface of the inner core plate to form a second negative pad at the position of the preset target point, wherein the surface area of the second negative pad is greater than the surface area of the first negative pad; Drilling from a first outer surface closest to the lower surface of the semi-finished substrate to perform controlled depth drilling on the material within the coverage area of the second negative pad, wherein the semi-finished substrate is a plate obtained by processing the inner core plate; the depth of the controlled depth drilling does not exceed the distance between the first outer surface and the upper surface; After controlled depth drilling, laser ablation is performed on the material within the coverage area of the first negative pad in the semi-finished substrate to machine a hole with a minimum cross-section that is the same size as the first negative pad, which serves as the preset target point.

2. The method according to claim 1, characterized in that After the controlled depth drilling, laser ablation is performed on the material within the coverage area of the first negative pad in the semi-finished substrate to form a hole with a minimum cross-section that is the same size as the first negative pad, including: Starting from the second outer surface of the semi-finished substrate closest to the upper surface, laser ablation is performed on the material within the coverage of the first negative pad until the ablated laser hole is connected to the drilled hole obtained by the depth-controlled drilling process.

3. The method according to claim 1, characterized in that If the depth-controlled drilling stops when contacting the upper surface, then after the depth-controlled drilling, laser ablation is performed on the material within the coverage area of the first negative pad in the semi-finished substrate to form a hole with a minimum cross-section that is the same size as the first negative pad, including: A laser beam is emitted from the first outer surface to perform laser ablation on the material within the coverage of the first negative pad, so as to deepen the drilled hole obtained by the depth-controlled drilling process.

4. The method according to claim 1, wherein The inner core board is a double-sided copper-clad board. During the process of machining the first alignment target point, drilling is started from the first outer surface closest to the lower surface of the semi-finished substrate, and before controlled depth drilling is performed on the material within the coverage area of the second negative pad, the method further includes: Browning the copper surface of the inner core board after patterning; After browning, semi-cured sheets are pressed onto both sides of the inner core board to obtain a frame layer board, which serves as a semi-finished substrate.

5. The method according to claim 1, wherein During the processing of the second alignment target point, before drilling from the first outer surface of the semi-finished substrate closest to the lower surface and performing controlled depth drilling on the material within the coverage area of the second negative pad, the method further includes: Grab the first alignment target point processed on the frame layer; According to the positioning of the first alignment target point, the device is embedded in the frame layer; After the device is embedded, the prepreg and the conductive layer are pressed onto both sides of the frame layer plate to obtain a device plate, which is a semi-finished substrate.

6. The method according to claim 1, characterized in that The method further comprises: Pasting a dry film on the soldering surface of the device board on which the second alignment target point is processed; grabbing a second alignment target on the device plate; According to the positioning of the second alignment target, a blind hole window pattern is processed on the device board after the dry film is pasted.

7. The method according to any one of claims 1 to 6, characterized in that The processing depth of the depth-controlled drilling is greater than the distance between the first outer surface and the lower surface.

8. The method according to any one of claims 1 to 6, characterized in that The first alignment targets include: laser contour alignment targets for device placement grooves and patch alignment targets for device patching.

9. A buried package substrate, characterized in that: The embedded packaging substrate includes a preset target point processed according to the substrate alignment target point processing method according to any one of claims 1-8.

10. An embedded package product, characterized in that: include: The embedded package substrate according to claim 9.

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