Processing method, drilling apparatus, system and hybrid substrate

Abstract

This application relates to the field of circuit board technology and provides a processing method, drilling equipment, system, and hybrid substrate. The processing method includes: placing a substrate to be drilled on a processing platform; the substrate to be drilled is formed by laminating a circuit layer and a ceramic layer with pre-drilled holes; removing material from the substrate along the depth direction of the pre-drilled holes according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed; the preset processing strategy includes at least mechanical drilling, where the drill bit is larger than or equal to the target hole diameter; wherein, when the pre-drilled hole is a through hole, mechanical drilling is performed according to preset first mechanical processing parameters; when the pre-drilled hole is a blind hole, material is removed along the depth direction by laser processing, and then mechanical drilling is performed along the depth direction. The embodiments of this application can achieve both processing quality and efficiency of the hole structure in a hybrid substrate with a ceramic layer.

Description

Technical Field

[0001] This application belongs to the field of circuit board technology, and particularly relates to a processing method, drilling equipment, system and hybrid substrate. Background Technology

[0002] With the rapid increase in computing power demands for Artificial Intelligence (AI), chip manufacturing processes are approaching their physical limits, making packaging technology a key direction for overcoming performance bottlenecks. CoWoP (Chip-on-Wafer-on-Platform PCB) packaging technology removes the traditional packaging substrate, allowing the chip to bond directly to the platform PCB. Simultaneously, removing the chip's surface cover allows the heat sink to directly contact the chip, significantly shortening signal paths and improving heat dissipation efficiency. However, CoWoP packaging places extremely stringent requirements on the flatness of the hybrid substrate. Existing hole structure processing methods are mostly applicable to traditional materials. For hybrid substrates containing ceramic layers, current methods typically use lasers to penetrate the entire substrate. When the ceramic layer is near the surface, this method tends to result in larger hole diameters, reducing the ceramic layer's surface area and affecting flatness, while also exhibiting extremely low processing efficiency. When the ceramic layer is close to the middle layer, laser processing struggles to effectively penetrate it, making processing difficult. Therefore, existing methods struggle to balance hole structure processing quality and efficiency. Summary of the Invention

[0003] This application provides a processing method, drilling equipment, system, and hybrid substrate that can balance the processing quality and efficiency of the hole structure.

[0004] The first aspect of this application provides a processing method, comprising: placing a substrate to be drilled on a processing platform, the substrate being formed by laminating a circuit layer and a ceramic layer having a pre-drilled hole; removing material from the substrate along the depth direction of the pre-drilled hole according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed, the preset processing strategy including at least mechanical drilling, wherein the drill bit of the mechanical drilling is greater than or equal to the target hole diameter, wherein when the pre-drilled hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters; when the pre-drilled hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

[0005] In some embodiments of the first aspect, the reserved hole is obtained by laser processing the ceramic layer according to preset second laser processing parameters; or, the reserved hole is formed by opening a window at the hole position of the reserved hole through exposure and development after covering the surface of the ceramic layer with a dry film, and etching the material in the windowed area.

[0006] In some embodiments of the first aspect, the preset processing strategy further includes: performing vibratory drilling along the depth direction by mechanical drilling, wherein the axial vibration frequency of the drill bit is greater than a preset frequency.

[0007] In some embodiments of the first aspect, the substrate to be drilled is formed by stacking and laminating a circuit layer and a ceramic layer in a preset layer sequence, wherein the ceramic layer is located in the middle layer and / or the surface layer of the substrate to be drilled after lamination.

[0008] In some embodiments of the first aspect, the reserved hole has a first aperture, which is less than or equal to the target aperture of the cross-layer hole structure, and mechanical drilling is used to remove material from the circuit layer and trim the hole wall of the reserved hole; or, the first aperture is greater than the target aperture of the cross-layer hole structure, and mechanical drilling is used to remove material from the circuit layer.

[0009] In some embodiments of the first aspect, before removing material along the depth direction of the reserved hole on the substrate to be drilled according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed, the method further includes: targeting the substrate to be drilled to determine the hole position of the reserved hole.

[0010] In some embodiments of the first aspect, targeting the substrate to be drilled to determine the location of the reserved hole includes: applying thermal excitation to the surface of the substrate to be drilled and acquiring the transient thermal field distribution on the surface of the substrate to be drilled using an infrared sensor; extracting the geometric center of the thermal anomaly region in the substrate to be drilled based on the transient thermal field distribution on the surface of the substrate to be drilled, and determining the location of the reserved hole based on the geometric center.

[0011] In some embodiments of the first aspect, the reserved hole has a conductive structure formed by local metallization; the substrate to be drilled is targeted to determine the hole position of the reserved hole, including: scanning the surface of the substrate to be drilled with a detection probe to determine the extreme point of the electromagnetic response signal, the electromagnetic response signal being generated by the conductive structure; and determining the hole position of the reserved hole based on the extreme point of the electromagnetic response signal.

[0012] In some embodiments of the first aspect, the associated location of the reserved hole has a processing mark with a preset morphology, the processing mark forming a micro-morphology on the surface of the substrate to be drilled during the pressing process; the substrate to be drilled is subjected to a target to determine the hole location of the reserved hole, including: detecting the location of the micro-morphology on the surface of the substrate to be drilled, and determining the hole location of the reserved hole based on the location of the micro-morphology.

[0013] In some embodiments of the first aspect, the substrate to be drilled is subjected to a target to determine the hole position of the reserved hole, including: obtaining the positional relationship between the pre-processed mechanical vias on the circuit layer and the reserved hole; detecting the mechanical vias on the substrate to be drilled to obtain the position of the mechanical vias; and determining the hole position of the reserved hole based on the position and positional relationship of the mechanical vias.

[0014] In some embodiments of the first aspect, the mechanical drilling process further includes: when the distance between the drill bit and the ceramic layer is less than a preset distance, controlling the drill bit to move along the depth direction according to a preset feed amount, and collecting the radial force of the drill bit in real time; detecting the drill bit offset from the center of the reserved hole based on the radial force; and adjusting the position of the drill bit based on the drill bit offset.

[0015] In some embodiments of the first aspect, the actual machining coordinates of the reserved hole are obtained by correcting the theoretical machining coordinates of the reserved hole based on the pressing offset, wherein the pressing offset is determined based on the pressing deformation field of the hybrid substrate.

[0016] In some embodiments of the first aspect, before pressing, the pre-drilled hole is filled with an insulating anti-plating material, which is used to reduce impurities adhering to the hole wall of the ceramic layer during mechanical drilling; after forming the cross-layer hole structure penetrating the ceramic layer and the circuit layer, the method further includes: removing the insulating anti-plating material.

[0017] In some embodiments of the first aspect, the cross-layer hole structure is a through hole or a blind hole.

[0018] A second aspect of this application provides a controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor; the processor executes the computer program to implement the steps of the above-described processing method.

[0019] A third aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described processing method.

[0020] The fourth aspect of this application provides a computer program product that, when run, causes the above-described processing method to be executed.

[0021] A fifth aspect of this application provides a drilling apparatus, comprising: a processing platform for placing and fixing a substrate to be drilled, the substrate being formed by laminating a circuit layer and a ceramic layer with a pre-drilled hole; a drilling device including a spindle and a drill bit disposed on the spindle; and a controller connected to the drilling device for controlling the drilling device to remove material from the substrate to be drilled along the depth direction of the pre-drilled hole according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. The preset processing strategy includes at least mechanical drilling, wherein the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the pre-drilled hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the pre-drilled hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then performing mechanical drilling along the depth direction according to preset second mechanical processing parameters.

[0022] A sixth aspect of this application provides a processing system, comprising: a pre-drilled hole processing device for processing pre-drilled holes in a ceramic layer; a pressing device for pressing a ceramic layer and a circuit layer having pre-drilled holes to obtain a substrate to be drilled; and a drilling device for removing material from the substrate to be drilled along the depth direction of the pre-drilled holes according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. The preset processing strategy includes at least mechanical drilling, wherein the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the pre-drilled hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the pre-drilled hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

[0023] The seventh aspect of this application provides a hybrid substrate, including a cross-layer interconnection structure, which is obtained by metallizing a cross-layer hole structure. The cross-layer hole structure is obtained by processing based on any one of the processing methods of the first aspect or based on the processing system of the sixth aspect.

[0024] In some embodiments of the seventh aspect, the hybrid substrate is used as the power layer of the circuit board in the CoWoP package, the surface of the circuit board is provided with a chip, and the cross-layer interconnection structure is used to electrically connect the pads of the chip with the circuit layer in the hybrid substrate.

[0025] In the embodiments of this application, pre-drilled holes are pre-processed in the ceramic layer, and the ceramic layer and circuit layer with pre-drilled holes are laminated to obtain a substrate to be drilled. Then, on the substrate to be drilled, material is removed along the depth direction of the pre-drilled holes according to a preset processing strategy that includes at least mechanical drilling, until a cross-layer hole structure is formed that penetrates the ceramic layer and the circuit layer. On the one hand, by processing with pre-drilled holes, the actual contact area and cutting force between the drill bit and the ceramic layer during mechanical drilling are significantly reduced, avoiding ceramic microcracks and local stress concentration caused by high rigidity impact when drilling large holes directly in the traditional way. This effectively controls the overall warpage and local deformation of the hybrid substrate and significantly improves flatness. For the ceramic layer located near the intermediate layer, the pre-drilled holes provide a guide channel for the drill bit, allowing the mechanical drilling to smoothly penetrate the original layer. The intermediate ceramic layer, which is difficult to process, is addressed by this method, overcoming the bottleneck of existing methods that cannot effectively process it. Furthermore, using a drill bit with a diameter greater than or equal to the target hole diameter to process the cross-layer hole structure allows for hole wall trimming, ensuring the cross-layer hole structure is continuous and the hole opening edges are smooth and without protrusions. This overcomes the shortcomings of traditional laser processing, which often results in excessively large hole diameters, reduced ceramic bearing area, and consequently decreased flatness. Simultaneously, mechanical drilling significantly improves efficiency compared to pure laser processing. Moreover, for different hole shapes, mechanical drilling is used directly for through holes to improve efficiency and hole wall quality. For blind holes, a combined laser-first, then mechanical drilling process is employed to avoid deviations or tool breakage due to uneven force distribution at the initial stage. Therefore, this application can balance the processing quality and efficiency of the hole structure. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0027] Figure 1 This is a schematic diagram illustrating the implementation flow of a processing method provided in an embodiment of this application; Figure 2 This is a schematic diagram illustrating the specific implementation process of the processing method for the cross-layer hole structure provided in the embodiments of this application; Figure 3 This is a schematic diagram illustrating the specific implementation process of the reserved hole processing provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the reserved hole provided in the embodiment of this application; Figure 5 This is a schematic diagram of the structure of the substrate to be drilled provided in the embodiments of this application; Figure 6This is a schematic diagram of the processing flow of the cross-layer hole structure when using laser processing for reserved holes, provided in an embodiment of this application. Figure 7 This is a schematic diagram of the processing flow of the cross-layer hole structure when using wet etching for pre-reserved holes, provided in an embodiment of this application. Figure 8 This is a schematic diagram of the specific process structure provided in the embodiments of this application for filling the reserved hole with insulating anti-plating material and removing it after mechanical drilling; Figure 9 This is a schematic diagram of the structure of a controller provided in an embodiment of this application; Figure 10 This is a schematic diagram of the drilling equipment provided in the embodiments of this application; Figure 11 This is a schematic diagram of the processing system provided in the embodiments of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are protected by this application.

[0029] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0030] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0031] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0032] CoWoP packaging places extremely stringent requirements on the flatness of hybrid substrates. Existing hole structure processing methods are mostly applicable to conventional materials. For hybrid substrates containing ceramic layers, current methods typically use lasers to penetrate the entire substrate. When the ceramic layer is near the surface, this method tends to result in larger hole diameters, reducing the ceramic layer's bearing area and consequently affecting flatness, while also exhibiting extremely low processing efficiency. When the ceramic layer is close to the middle layer, laser processing struggles to effectively penetrate it, making processing difficult. Therefore, existing methods cannot balance hole structure processing quality and efficiency. Based on this, this application proposes a processing method that controls the overall warpage and local deformation of the hybrid substrate, overcoming the bottleneck of existing methods' inability to effectively process the middle ceramic layer. Simultaneously, it utilizes mechanical drilling to overcome the shortcomings of traditional laser processing, such as larger hole diameters, reduced ceramic bearing area leading to decreased flatness, and low processing efficiency. This method can achieve a balance between hole structure processing quality and efficiency in hybrid substrates with ceramic layers.

[0033] To illustrate the technical solution of this application, specific embodiments are described below.

[0034] Figure 1 The illustration shows a schematic diagram of the implementation process of a processing method provided in an embodiment of this application. This method can be applied to the controller of a drilling equipment.

[0035] Specifically, the above processing method may include the following steps S101 to S102.

[0036] Step S101: Place the substrate to be drilled on the processing platform.

[0037] In the embodiments of this application, the substrate to be drilled is a substrate formed by laminating a circuit layer and a ceramic layer with pre-drilled holes. The overall thickness of the substrate can range from 2mm to 6mm, and the thickness of the ceramic layer can range from 0.25mm to 0.5mm. To improve the flatness of the substrate, the ceramic layer can be distributed in the inner layer (middle layer) of the substrate or near the two sides of the substrate, or distributed on both sides and in the middle of the substrate as needed; no specific limitation is made here. The processing platform is a mechanism on the drilling equipment used to place and fix the substrate to be drilled.

[0038] The ceramic layer is a sheet-like substrate made of materials such as alumina, aluminum nitride, or silicon nitride, which can be used to improve heat dissipation efficiency in CoWoP packaging. At least one pre-drilled hole can be formed at a specific processing location on the ceramic layer. A pre-drilled hole refers to a pre-formed hole structure with a first aperture. The first aperture D1 of the pre-drilled hole can be set according to processing requirements; it can be set to be less than or equal to the target aperture D0 of the cross-layer hole structure (i.e., the design diameter of the cross-layer hole structure on the final hybrid substrate), or it can be set to be greater than the target aperture D0 of the cross-layer hole structure. This application does not impose any limitations on this. For example, the first aperture D1 can be set to 0.1mm-0.3mm, and the target aperture D0 can be set to 0.2mm. The processing of the pre-drilled hole is equivalent to pre-constructing a stress relief boundary, while reducing the amount of ceramic material in subsequent processing. It also acts as a guide in subsequent mechanical drilling and effectively prevents resin from adhering to the hole wall of the ceramic substrate, ensuring the heat dissipation effect of the finished product.

[0039] The circuit layer is a composite structure made of organic dielectric materials and copper foil circuitry, specifically referring to a printed circuit board (PCB), which is responsible for signal transmission and power distribution. At least one ceramic layer with pre-drilled holes is laminated with at least one circuit layer to form a single, drillable substrate.

[0040] Step S102: On the substrate to be drilled, material is removed along the depth direction of the reserved hole according to a preset processing strategy until a cross-layer hole structure is formed that penetrates the ceramic layer and the circuit layer.

[0041] Specifically, the substrate to be drilled after lamination is placed on a CNC drilling machine. According to a preset processing strategy, material is removed along the depth direction of the pre-drilled hole (i.e., from the surface of the substrate to be drilled perpendicularly inward) until a cross-layer hole structure is formed that penetrates the ceramic layer and the circuit layer. Here, removing material along the depth direction can include the removal of the entire material column from the upper surface to the lower surface of the circuit layer, as well as removing any ceramic layer hole walls or adhesive residue that may have flowed in during lamination.

[0042] The preset machining strategy may include at least a mechanical drilling process, and the diameter D2 of the selected drill bit is set to be greater than or equal to the target hole diameter D0 of the cross-layer hole structure. Since pre-drilled holes have been pre-machined on the ceramic layer, the drill bit primarily cuts the softer circuit layer material during subsequent mechanical drilling. Because the drill bit diameter D2 is set to be greater than or equal to the target hole diameter D0, the drill bit can remove all the material covering the pre-drilled hole area on the circuit layer in one pass, while simultaneously eliminating any steps or residue buildup at the hole opening that may result from pressing, forming a smooth cross-layer hole structure. In a machining scenario, the machining parameters for mechanical drilling may include: spindle speed, which can be set to 90krpm-150krpm; feed rate, which can be set to 0.08m / min-0.12m / min; and retraction rate, which can be set to 0.8m / min-1.2m / min.

[0043] As mentioned earlier, in some scenarios, the first aperture D1 of the reserved hole can be set to be less than or equal to the target aperture D0 of the cross-layer hole structure. In this case, mechanical drilling can be used to remove material from the circuit layer and trim the hole wall of the reserved hole. Specifically, since the first aperture D1 of the reserved hole is small, while the diameter D2 of the drill bit is greater than or equal to the target aperture D0, the drill bit can remove all the material covering the reserved hole area on the circuit layer in one go. When passing through the ceramic layer, the drill bit contacts the hole wall of the reserved hole through its side edge and grinds it, expanding the reserved hole from the first aperture D1 to the target aperture D0, while making the hole wall smooth.

[0044] In another application scenario, the first aperture D1 of the reserved hole can be set to be larger than the target aperture D0 of the cross-layer hole structure. In this case, mechanical drilling can be used to remove material from the circuit layer. That is, because the aperture of the reserved hole is larger, only the original circuit board material needs to be penetrated in the subsequent machining, without processing the ceramic layer material, which can improve the overall processing efficiency and accuracy.

[0045] For easier understanding, please refer to Figure 2 , Figure 2 The processing procedure of the hybrid substrate of this application is shown. Figure 2 (a) represents the initial state of the ceramic layer, which is formed after processing. Figure 2 The pre-drilled hole shown in (b) is laminated with the circuit to form the substrate to be drilled shown in (c), and finally the material is removed to form the hybrid substrate with the cross-layer hole structure shown in (d).

[0046] When the reserved hole is a through hole, the preset processing strategy is to perform mechanical drilling according to the preset first machining parameters.

[0047] The first set of machining parameters refers to a set of process parameters specifically used to remove the circuit layer and residues inside the hole after the pre-drilled hole has been completed. These parameters may include: drill bit rotation speed, feed rate, retraction depth, and number of pecking passes. During mechanical drilling, the drill bit feeds along the depth direction of the pre-drilled hole. Since there is already a through hole below, the drill bit tip first contacts and cuts the material covering the entrance area of ​​the pre-drilled hole on the circuit layer. It then enters the cavity of the pre-drilled hole, using its side cutting edge to scrape away residual adhesive residue on the hole wall and slightly enlarge the ceramic hole wall. Because the pre-drilled hole is completely completed, the bottom of the drill bit is not subjected to resistance from the ceramic material. The cutting load comes almost entirely from the circuit layer and residues inside the hole, thereby significantly reducing mechanical stress and tool temperature rise.

[0048] In one application scenario, a reciprocating feed machining mode with a preset pulse frequency can also be used for mechanical drilling. In this machining mode, the drill bit does not cut continuously, but rather the highly rotating tool achieves high-frequency intermittent feed / vibration cutting, typically driven by high-frequency pulses (≥500Hz). In practical tests, the high-frequency short-pulse reciprocating feed machining mode can improve the machining efficiency and accuracy of ceramic layers and extend the tool life. In a specific embodiment, an air-bearing spindle and an oil mist spraying device can be configured. By controlling the air-bearing spindle to drill along the axial direction at a preset feed speed, and controlling the spindle of the air-bearing spindle to perform preset reciprocating micro-motions while spraying oil mist during machining, the reciprocating micro-motions of the drill bit are controlled, and the machining temperature is reduced. This allows the drill bit to periodically contact and separate from the circuit board during high-speed rotating drilling. Alternatively, a linear motor can be configured on the spindle. For implementation directions, please refer to the existing technology. To avoid redundancy, further discussion is not provided.

[0049] When the reserved hole is a blind hole, the preset processing strategy may include: removing material along the depth direction by laser processing according to the preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to the preset second mechanical processing parameters.

[0050] The first laser processing parameters are a set of process parameters specifically used for removing the remaining ceramic layer at the bottom of the blind hole. They differ from the second laser processing parameters used when processing blind holes on a pure ceramic layer. They typically include higher single-pulse energy, longer pulse width (e.g., switching from picoseconds to nanoseconds) or more scans to accommodate the laser's need to penetrate any possible adhesive residue and variations in thickness.

[0051] A laser beam is used to irradiate downwards from the opening along the depth direction of the pre-drilled hole, vaporizing and removing residual ceramic material at the bottom of the blind hole layer by layer until the ceramic layer is penetrated, forming a through hole. During this process, the laser also removes material covering the opening area on the circuit layer, as well as any adhesive residue that may flow into the blind hole. Then, mechanical drilling is performed on the drilled holes that still have a heat-affected zone on the wall or are undersized, according to preset second machining parameters. The second machining parameters are a set of parameters specifically used for subsequent hole enlargement and wall finishing in blind hole solutions. The drill bit diameter D2 is greater than or equal to the final target hole diameter D0, which can remove the recast layer, burrs, and hole wall protrusions remaining from laser processing, and precisely control the final hole diameter.

[0052] Accordingly, the via structure can be a blind via or a through via. This via structure can be used to form a via interconnect structure through metallization, thereby achieving electrical connection between the circuit layer and the external chip circuit, while also forming an efficient heat dissipation channel. Metallization refers to depositing a continuous conductive metal layer on the inner wall of the via using methods such as chemical copper plating, electroplating copper, or filling with conductive paste.

[0053] In some scenarios, the aforementioned hybrid substrate is used as the power layer of the circuit board in a CoWoP package. Chips are disposed on the surface of the circuit board, and cross-layer interconnect structures are used to electrically connect the chip's pads to the circuit layers within the hybrid substrate. Specifically, in the CoWoP packaging architecture, the chip can be bonded to the upper surface of the PCB, which is constructed from the hybrid substrate as the power layer, via a silicon interposer.

[0054] In the embodiments of this application, pre-drilled holes are pre-processed in the ceramic layer, and the ceramic layer and circuit layer with pre-drilled holes are laminated to obtain a substrate to be drilled. Then, on the substrate to be drilled, material is removed along the depth direction of the pre-drilled holes according to a preset processing strategy that includes at least mechanical drilling, until a cross-layer hole structure is formed that penetrates the ceramic layer and the circuit layer. On the one hand, by processing with pre-drilled holes, the actual contact area and cutting force between the drill bit and the ceramic layer during mechanical drilling are significantly reduced, avoiding ceramic microcracks and local stress concentration caused by high rigidity impact when drilling large holes directly in the traditional way. This effectively controls the overall warpage and local deformation of the hybrid substrate and significantly improves flatness. For the ceramic layer located near the intermediate layer, the pre-drilled holes provide a guide channel for the drill bit, allowing the mechanical drilling to smoothly penetrate the original layer. The intermediate ceramic layer, which is difficult to process, is addressed by this method, overcoming the bottleneck of existing methods that cannot effectively process it. Furthermore, using a drill bit with a diameter greater than or equal to the target hole diameter to process the cross-layer hole structure allows for hole wall trimming, ensuring the cross-layer hole structure is continuous and the hole opening edges are smooth and without protrusions. This overcomes the shortcomings of traditional laser processing, which often results in excessively large hole diameters, reduced ceramic bearing area, and consequently decreased flatness. Simultaneously, mechanical drilling significantly improves efficiency compared to pure laser processing. Moreover, for different hole shapes, mechanical drilling is used directly for through holes to improve efficiency and hole wall quality. For blind holes, a combined laser-first, then mechanical drilling process is employed to avoid deviations or tool breakage due to uneven force distribution at the initial stage. Therefore, this application can balance the processing quality and efficiency of the hole structure.

[0055] Furthermore, by pre-processing reserved holes, the amount of ceramic material processed during mechanical drilling can be reduced, thereby reducing heat accumulation, tool wear and the risk of tool breakage, and extending tool life.

[0056] This application does not impose any restrictions on the processing method of the reserved holes.

[0057] Specifically, in some embodiments of this application, the aforementioned reserved hole can be obtained by laser processing the ceramic layer according to preset second laser processing parameters.

[0058] Specifically, the second set of laser processing parameters is a set of process parameters specifically designed for the ablation of ceramic materials, and may include laser wavelength, pulse width, single pulse energy, repetition frequency, scanning speed, and number of processing cycles. Specifically, the laser used in the above laser processing can be an ultrashort pulse laser (including but not limited to, for example, nanosecond lasers, picosecond lasers, femtosecond lasers, etc.), and the laser emitting an ultrashort pulse laser beam can be used to process pre-drilled holes in the ceramic layer. In practical applications, a laser that can provide suitable laser pulse wavelength and pulse frequency parameters can be selected according to processing requirements. The power, spot size, and number of pulses of the laser beam emitted by the laser can all be set according to processing requirements. Preferably, the laser can be an ultrafast laser that generates ultrafast lasers (including picosecond lasers, femtosecond lasers, etc.).

[0059] It is understandable that lasers emitting ultrashort pulse laser beams include ultrafast lasers and nanosecond lasers. Ultrafast lasers emit laser beams with pulse widths on the order of picoseconds, while nanosecond lasers emit laser beams with pulse widths on the order of nanoseconds. For ceramic material layers, the extremely short pulse durations of ultrafast and nanosecond lasers enable them to possess high peak power and wide spectral bandwidth, concentrating laser energy within a very small temporal and spatial range. This induces multiphoton absorption and / or avalanche ionization at the processing location in the ceramic layer, breaking the molecular chains of the material, causing it to vaporize, and forming smaller particles, thus achieving rapid material removal. Furthermore, the interaction between ultrashort pulse lasers and the substrate is primarily a cold processing process, which can further reduce the thermal impact on the surrounding structure during processing, facilitating the acquisition of better processed cross-sectional morphology.

[0060] like Figure 3 As shown, by controlling the laser according to the second laser processing parameters, the laser beam emitted by the laser can be incident on the surface of the ceramic layer along the depth direction. The laser energy is highly concentrated and vaporizes the ceramic material, forming a pre-drilled hole with a first aperture. In this way, the laser beam vaporizes the material through a high-energy beam without physical contact with the ceramic layer, thus avoiding cutting or impact forces and helping to maintain flatness. Furthermore, by adjusting the spot diameter, scanning path, and number of processing passes, precise processing of pre-drilled holes with different apertures, depths, and cross-sectional shapes can be achieved.

[0061] In some other embodiments of this application, the reserved hole is formed by opening a window at the hole position after covering the surface of the ceramic layer with a dry film, and etching the material in the windowed area.

[0062] Specifically, dry film is a solid photosensitive film composed of photosensitive resin, photoinitiator, and binder. Under ultraviolet light irradiation, it can undergo polymerization or depolymerization reactions, thereby altering its solubility in the developer. For example... Figure 2As shown, a dry film is first applied to the surface of the ceramic layer. After applying the dry film, an exposure process is used: a mask (whose light-transmitting pattern corresponds to the actual processing position and aperture of the pre-drilled hole) is placed above the dry film. A laser beam is controlled using Laser Direct Imaging (LDI) to selectively irradiate the dry film, altering the photosensitive characteristics of the pre-drilled hole area. Development is then performed: the dry film in the exposed area (positive dry film) or the unexposed area (negative dry film) is dissolved using a developer, creating a windowed area on the dry film that matches the shape of the pre-drilled hole. This process is called windowing. After windowing, the surface of the ceramic layer, except for the pre-drilled hole area, is protected by the dry film. Next, an etching process is used, typically wet etching (using hydrofluoric acid-based or phosphoric acid-based etching solutions). The etching solution contacts the ceramic material through the window on the dry film, selectively dissolving and removing the ceramic in the windowed area to form a pre-drilled hole with a first aperture. Finally, the remaining dry film is removed. Since etching is a chemical dissolution process, it almost never forms a recast layer, microcracks, or thermal stress around the hole walls, ensuring that the circuit layer materials (such as ABF, FR-4) do not carbonize or degenerate due to residual heat during subsequent lamination, thereby ensuring the flatness of the substrate.

[0063] In addition, the reserved holes can be processed in other ways, such as by alternating mechanical drilling and laser processing to form the reserved holes on the ceramic layer. This application does not limit this.

[0064] In some embodiments of this application, such as Figure 4 As shown, the reserved hole can be a through hole or a blind hole. A through hole is formed by drilling through the ceramic layer during the machining of the reserved hole. A blind hole, on the other hand, leaves a predetermined thickness of ceramic material at the bottom of the ceramic layer.

[0065] Specifically, when the first diameter of the reserved hole is less than or equal to the thickness of the ceramic layer, the reserved hole can be a through hole or a blind hole. When the first diameter of the reserved hole is greater than the thickness of the ceramic layer, it is more difficult to drill through the ceramic layer (for example, the aforementioned laser processing method is difficult to process to the bottom of the corresponding ceramic layer in one go), and the reserved hole can be a blind hole.

[0066] It should be noted that the number of holes on the ceramic layer and the processing position (i.e., the actual processing coordinates) of each hole can be determined according to the design requirements of the hole structure on the final hybrid substrate.

[0067] In some embodiments of this application, the actual machining coordinates of the reserved hole are obtained by correcting the theoretical machining coordinates of the reserved hole based on the pressing offset, wherein the pressing offset is determined based on the pressing deformation field of the hybrid substrate.

[0068] Specifically, due to the significant difference (approximately 3 to 4 times) in the coefficient of thermal expansion (CTE) between the ceramic layer and the circuit layer, the position of the pre-reserved holes within the ceramic layer is prone to nonlinear displacement relative to the theoretical processing coordinates during subsequent lamination. Therefore, when processing the ceramic layer, the theoretical processing coordinates can be pre-compensated by offsetting them in the reverse direction. Specifically, by establishing a finite element thermodynamic model based on the material parameters of the hybrid substrate (such as CTE, elastic modulus, thickness, number of layers, etc.), the lamination deformation field during the lamination process (including heating, pressurization, heat preservation, and cooling) can be simulated, obtaining the lamination offset (Δx, Δy) of the pre-reserved hole positions. Then, the theoretical processing coordinates of the pre-reserved holes are corrected based on the lamination offset, resulting in actual processing coordinates = theoretical processing coordinates - lamination offset (Δx, Δy). Thus, after lamination, this lamination offset (Δx, Δy) can cancel out the thermal deformation of the hole positions, ensuring that the actual hole positions match the processing requirements of the cross-layer hole structure.

[0069] It is understandable that a uniform pressing offset (Δx, Δy) can be used for all reserved holes, or a corresponding pressing offset (Δx, Δy) can be calculated for each reserved hole separately. Synchronous compensation for each reserved hole ensures the positional accuracy of each hole.

[0070] It should be noted that the above finite element thermodynamic model can employ machine learning algorithms to learn the relevant parameters of the conversion between material and deformation field through iterative training, thereby making the compression offset more accurate.

[0071] After the pre-drilled holes are processed, the circuit layer and the ceramic layer with the pre-drilled holes can be laminated together.

[0072] In some embodiments of this application, the substrate to be drilled is formed by laminating a circuit layer and a ceramic layer in a preset layer sequence. In the preset layer sequence, the ceramic layer may be located in the middle layer and / or the surface layer of the substrate to be drilled after lamination.

[0073] Specifically, multi-layered composite structures can be constructed according to design requirements, for example: please refer to Figure 5 In (a) and (c), the multilayer composite structure formed by stacking can be a structure of circuit layer (first layer), ceramic layer (second layer), and circuit layer (third layer), in which case the ceramic layer is only located in the middle layer; or, please refer to Figure 5 In (b) and (d), the multi-layered composite structure formed by stacking can be a structure of ceramic layer (first layer), circuit layer (second layer), and ceramic layer (third layer), in which case the ceramic layer is only located on the surface. Among them, (a) and (b) correspond to reserved holes processed by laser, and (c) and (d) correspond to reserved holes processed by wet etching.

[0074] Understandable Figure 5 The diagram illustrates a three-layer composite structure, but in practical applications, more material layers can be stacked. For composite structures with more than three layers, the number of ceramic layers can be less than or equal to the number of circuit layers, and the ceramic layers can be distributed in the middle layer, the surface layer, or both the middle layer and the surface layer; no specific limitation is made here.

[0075] The lamination process can be achieved by layer-by-layer lamination or one-time lamination. Layer-by-layer lamination involves laminating the first two material layers, then stacking the third material layer on top and laminating, and so on. One-time lamination involves stacking all ceramic layers and circuit layers in a preset order and laminating them all at once.

[0076] During lamination, the layers are stacked on the lamination equipment tray according to a preset sequence. A prepreg can be placed between the circuit layer and the ceramic layer, or the resin of the circuit layer itself can soften and flow under heat and pressure to fill the microscopic interface between the ceramic layer and the circuit layer. Subsequently, high temperature and high pressure are applied in a vacuum environment and maintained for a certain period of time to allow the organic resin to fully cure, bonding the ceramic layer and the circuit layer together to form a substrate to be drilled. For large-sized multilayer composite structures, the lamination plate can be divided into multiple temperature and pressure independently controlled zones (e.g., a 3×3 matrix). Each temperature and pressure independently controlled zone controls the temperature and pressure according to the actual stacked structure below it.

[0077] Understandably, ceramic layers possess high rigidity, low coefficient of thermal expansion, and high thermal conductivity, but are difficult to implement with fine circuitry; circuit layers (containing organic materials and copper) can achieve high-density wiring, but their CTE is relatively high. Through lamination, a composite structure with both rigidity and flexibility, and both high and low CTE, can be constructed in the thickness direction, so that the equivalent CTE of the overall substrate is between that of ceramic and organic materials. At the same time, the ceramic layer acts as a rigid skeleton to suppress overall warping, while the circuit layer provides wiring functionality as a signal transmission layer, realizing multi-layer high-density interconnection.

[0078] During the lamination process, segmented heating and cooling, along with stepped pressure curves, can be used. Specifically, low-pressure preheating (e.g., 100℃, 5kg / cm²) can be used to soften the resin, followed by high-pressure holding (e.g., 200℃, 35kg / cm²) to allow the resin to fully flow and fill the interface, and finally, slow cooling to room temperature (e.g., cooling rate ≤3℃ / min) can be employed. This avoids thermal stress concentration between the ceramic layer and the circuit layer due to excessively rapid heating or sudden cooling, helping to control the overall warpage of the substrate after lamination.

[0079] Furthermore, during the lamination process, a buffer film (such as polyimide or modified PTFE film) can be placed between the ceramic layer and the circuit layer to absorb the uneven local pressure caused by surface roughness or slight warping between the ceramic layer and the circuit layer, so that the interface height is consistent after lamination and the overall flatness is improved.

[0080] It should be noted that, please refer to Figure 3 , Figure 5 For laser processing of pre-drilled holes, the laser inlet diameter is usually larger than the outlet diameter, while the opposite is true for etching (i.e., the inlet diameter is smaller than the outlet diameter). To improve machining accuracy by providing a more significant guiding effect for mechanical drilling, the pressing method and the direction of mechanical drilling can be configured according to the forming method of the pre-drilled hole.

[0081] like Figure 6 (a) to (d) are shown, where (a) represents pre-drilled hole processing, (b) represents pressing, and (c) represents mechanical drilling. In some embodiments, if the pre-drilled hole is processed by laser, the mechanical drilling direction can be configured to be consistent with the laser processing direction, that is, the drill bit enters from the large-diameter side of the pre-drilled hole and advances along the direction of hole diameter tapering.

[0082] It should be noted that, as Figure 6 As shown in (d) to (e), since the inlet diameter of the reserved hole is usually larger than the outlet diameter, especially when the first hole diameter is larger than the target hole diameter, mechanical drilling can be performed according to the hole diameter on the smaller diameter side of the reserved hole to form the hybrid substrate shown in (e).

[0083] In other embodiments, if the pre-drilled hole is formed by etching, the ceramic layer can be flipped before lamination so that the large-diameter side formed by etching faces upward (i.e., towards the mechanical drilling side of the substrate to be drilled), so that the mechanical drilling also enters from the large-diameter side. Specifically, such as Figure 7 As shown in (a) to (e), (a) indicates pre-drilled holes, (c) indicates pressing, and (d) indicates mechanical drilling. Figure 6 Compared to the addition of the flip shown in (b), a hybrid substrate as shown in (e) is formed.

[0084] In this way, mechanical drilling enters along the flaring direction (large diameter end) of the reserved hole, so that the reserved hole plays a significant guiding and centering role in the subsequent cross-layer hole processing, further improving the processing accuracy.

[0085] In some embodiments of this application, material is removed from the substrate to be drilled along the depth direction of the reserved hole according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. This may include: determining the processing sequence of each processing method according to the preset processing strategy, and processing according to the processing sequence.

[0086] Specifically, when the preset processing strategy only includes mechanical drilling, a drill bit of the corresponding diameter can be selected according to the target hole diameter, and the drill bit can be controlled to remove material along the depth direction of the reserved hole until a cross-layer hole structure is formed that penetrates the ceramic layer and the circuit layer. The drill bit can be made of cemented carbide or diamond-coated drill bit to adapt to the organic resin, fiberglass cloth and copper foil in the circuit layer, while being able to perform micro-cutting on the hole wall of the ceramic layer.

[0087] When the preset processing strategy includes mechanical drilling and other processing methods (such as laser processing), the corresponding processing methods can be used sequentially along the depth direction to remove material according to the processing order between different processing methods. Since the drill bit is larger than or equal to the target hole diameter during mechanical drilling, mechanical drilling can achieve the effect of hole wall shaping. Therefore, mechanical drilling can be set as the last step in all processing methods. For example, laser processing can be used first for material removal, and then mechanical drilling can be used for both material removal and shaping.

[0088] The preset processing strategy can also be: to perform vibratory drilling along the depth direction by mechanical drilling, and the axial vibration frequency of the drill bit is greater than the preset frequency (e.g., greater than 15kHz).

[0089] Specifically, high-frequency vibration causes the drill bit to make intermittent contact with the ceramic material, instantly detaching it from the workpiece surface. This significantly reduces the average cutting force and frictional heat, preventing the drill bit from sticking or getting stuck at the bottom of the blind hole due to continuous cutting. Therefore, the circuit layer material and the ceramic layer material are removed simultaneously.

[0090] In some embodiments of this application, before pressing, the reserved hole is filled with an insulating anti-plating material, which is used to reduce impurities adhering to the hole wall of the ceramic layer during mechanical drilling.

[0091] Specifically, after forming the pre-drilled hole through laser processing or wet etching, a temporary material with insulating properties can be filled into the hole. The insulating anti-plating material can be selected from non-polar resins (such as polytetrafluoroethylene PTFE), polymers containing mercapto groups (-SH), anti-copper plating resin inks, etc., and its function is to act as a sacrificial protective layer during subsequent mechanical drilling. Figure 8 As shown, (a) represents the pre-drilled hole processing, and (b) represents the filling with insulating anti-plating material. After filling, the ceramic layer and the circuit layer are laminated together, precisely aligned using a target-grabbing system, and then... Figure 8 As shown in (c), mechanical drilling can be used for material removal. When the ceramic layer is located in the intermediate layer, the drill bit can sequentially penetrate the circuit layer material, the insulating resist material, and the circuit layer material to ultimately form the desired cross-layer hole structure. Because the drill bit cuts the circuit layer before entering the insulating resist material, resin debris generated during circuit layer processing is blocked or carried away by the insulating resist material, thus significantly reducing or even eliminating resin adhesion to the ceramic layer hole walls.

[0092] Accordingly, after forming the trans-layer via structure penetrating the ceramic layer and the circuit layer, the process may also include: removing the insulating resist material. Specifically, such as... Figure 8As shown in (d), after the cross-layer hole structure is processed, a post-processing step can be added: using a specific chemical solution to completely dissolve and rinse away the residual insulating and anti-plating material inside the hole. After removing the insulating and anti-plating material, the hole wall restores its original clean surface. This utilizes the high efficiency and alignment accuracy of mechanical drilling while avoiding the risk of resin contamination of the ceramic layer's heat dissipation channels, thus ensuring the processing quality of the hybrid substrate.

[0093] In some embodiments of this application, the mechanical drilling process may further include: when the distance between the drill bit and the ceramic layer is less than a preset distance, controlling the drill bit to move along the depth direction according to a preset feed amount, and collecting the radial force of the drill bit in real time; detecting the drill bit offset from the center of the reserved hole based on the radial force; and adjusting the position of the drill bit based on the drill bit offset.

[0094] Specifically, a multi-dimensional micro-force sensor can be installed on the spindle of the mechanical drilling machine to collect axial force Fz and radial force Fx / Fy. When the drill bit descends to a distance less than a preset distance from the ceramic layer, and the surface is about to contact the ceramic layer, the drill bit can be controlled to move along the depth direction with a preset feed rate. This preset feed rate can be less than a preset threshold, such as 0.01 mm / step, to achieve gradual advance. During the drill bit feed process, the radial force Fx / Fy can be collected in real time. If Fx / Fy is less than or equal to the preset threshold (e.g., 0), it indicates that the drill bit is at the center of the reserved hole; if Fx / Fy is greater than the preset threshold, it indicates that the drill bit has deviated from the hole center and touched one side of the ceramic hole wall. Therefore, based on the amplitude and direction of Fx / Fy, the drill bit offset can be calculated in real time, and a correction command can be output to the controller to adjust the position of the drill bit.

[0095] The process of acquiring radial force, calculating drill bit offset, and adjusting drill bit position can be performed periodically. After each cycle, drilling is executed at the default feed rate. For example, after 1 to 3 cycles, the drill bit will automatically correct itself to the center of the hole, and through drilling can be completed at the normal feed rate. In this way, the offset problem caused by thermal deformation can be solved without relying on any markings before pressing, and each hole position can be compensated in real time, ensuring that the machining accuracy is not affected by the overall deformation of the board surface.

[0096] It should be noted that, in order to reduce thermal stress, cooling operations can be performed during mechanical drilling. Specifically, a small amount of coolant (such as an alcohol-water mixture or oil mist) can be sprayed into the contact area between the drill bit and the substrate during mechanical drilling, or low-temperature cold air can be used to reduce frictional heat, avoid local thermal expansion that could lead to hole diameter errors and resin softening and adhesion at the hole opening, and improve flatness.

[0097] Considering that the drill bit needs to contact the sidewall of the reserved hole in the ceramic layer and perform grinding, the wear degree of the drill bit can be determined by monitoring the spindle load current or the acoustic signal when the drill bit contacts the substrate. When the wear degree of the drill bit exceeds the threshold, the drill bit can be automatically replaced to prevent the worn drill bit from causing the hole diameter to be too small, the hole wall to be rough, or the substrate to be unevenly deformed.

[0098] To ensure accurate alignment, the process involves removing material along the depth direction of the pre-drilled hole on the substrate to be drilled according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. This process also includes: targeting the substrate to be drilled to determine the position of the pre-drilled hole.

[0099] In the embodiments of this application, before removing material along the depth direction of the reserved hole according to the preset processing strategy, it is necessary to first obtain the actual spatial position of the reserved hole in the substrate to be drilled (i.e., the hole position of the reserved hole). This action is called target gripping. After target gripping is completed, the theoretical drilling coordinates can be automatically corrected to the actual drilling coordinates based on the hole position of the reserved hole, and the drill bit or other processing device can be driven to perform the action of removing material in the depth direction according to the actual drilling coordinates.

[0100] In some embodiments of this application, the method of targeting the substrate to be drilled to determine the location of the reserved hole includes: applying thermal excitation to the surface of the substrate to be drilled and acquiring the transient thermal field distribution on the surface of the substrate to be drilled through an infrared sensor; extracting the geometric center of the thermal anomaly region in the substrate to be drilled based on the transient thermal field distribution on the surface of the substrate to be drilled, and determining the location of the reserved hole based on the geometric center.

[0101] Specifically, after lamination, a uniform pulsed thermal excitation (such as laser pulse heating or infrared flash) is applied to the surface of the substrate to be drilled. Due to its high thermal conductivity, the ceramic layer rapidly conducts heat to the surface, while the location of the pre-drilled ceramic hole forms a localized thermal anomaly area due to its low thermal conductivity. A high-resolution infrared thermal imager (frame rate ≥1000Hz) and other infrared sensors are used to acquire the transient thermal field distribution on the surface of the substrate to be drilled. The geometric center of the thermal anomaly area in the transient thermal field distribution can be extracted using image processing algorithms. This geometric center is the projection coordinate of the pre-drilled hole on the surface of the substrate to be drilled. Therefore, the geometric center can be used as the hole position of the pre-drilled hole and transmitted to the controller to achieve precise alignment for drilling. In this way, based on the difference in thermal conductivity, the hole positions of all pre-drilled holes on the entire board can be identified in a single infrared imaging operation, compensating for displacement deviations caused by lamination.

[0102] In some other embodiments of this application, the reserved hole has a conductive structure formed by local metallization. Specifically, after laser drilling, the hole wall of the reserved hole can be selectively metallized with a Ti or Cu thin film with a thickness of 0.1~0.5μm, thereby forming a conductive structure with a diameter consistent with the target hole diameter.

[0103] At this point, targeting the substrate to be drilled to determine the location of the reserved hole can include: scanning the surface of the substrate to be drilled with a detection probe to determine the extreme points of the electromagnetic response signal, which is generated by the conductive structure; and determining the location of the reserved hole based on the extreme points of the electromagnetic response signal.

[0104] The detection probe can be a high-density capacitor array scanning head or a planar eddy current array. The electromagnetic response signal acquired by the capacitor array scanning head is a capacitance signal, while the electromagnetic response signal acquired by the planar eddy current array is a mutual inductance signal.

[0105] Specifically, the pre-metallized ceramic layer with hole walls is laminated with the circuit layer. After lamination, a detection probe rapidly scans the surface of the substrate to be drilled. The conductive structure of the hole wall generates a local electromagnetic response signal in an electric field. By extracting the extreme points of the electromagnetic response signal, the location of the extreme point is the hole center position. Therefore, the location of the extreme point can be used as the hole position for the reserved hole and transmitted to the controller to achieve precise alignment for drilling. Since the conductive structure is a permanent mark embedded in the hole wall of the ceramic layer, it is not affected by the lamination process, and the extreme point can be reliably obtained. Furthermore, capacitive / eddy current induction is radiation-free, has a fast scanning speed, and the induction positioning accuracy can reach ±5μm.

[0106] In some other embodiments of this application, the associated positions of the pre-drilled holes have processing marks with a predetermined morphology. These processing marks form a micro-morphology on the surface of the substrate to be drilled during the lamination process. The associated position of the pre-drilled hole refers to the position where it is separated from the pre-drilled hole within a predetermined distance for each pre-drilled hole. Specifically, when processing the pre-drilled holes on the ceramic layer, equally spaced micro-processing marks are simultaneously processed on the outer side of the hole edge. These processing marks can be micro-annular bosses or grooves, such as four symmetrical pits approximately 50 μm in diameter and 10 μm in depth.

[0107] At this point, a target is gripped on the substrate to be drilled to determine the location of the reserved hole, including: detecting the location of the micro-morphology on the surface of the substrate to be drilled, and determining the location of the reserved hole based on the location of the micro-morphology.

[0108] Specifically, during lamination, the micro-stress generated by the machining mark ring can create detectable morphological undulations on the surface of the circuit layer. These micro-morphologies can be identified using phase deflection or structured light scanning (resolution at the 0.1 μm level). The center of these micro-morphologies can be used as the geometric center of the machining mark, and the position of the pre-drilled hole can be determined using the positional relationship between the machining mark and the pre-drilled hole. In this way, target acquisition can be completed based on optical inspection, and the machining mark can be fabricated simultaneously during the pre-drilled hole processing in the ceramic layer, requiring no additional processing.

[0109] In some other embodiments of this application, the process of targeting the substrate to be drilled to determine the position of the reserved hole may include: obtaining the positional relationship between the pre-processed mechanical vias on the circuit layer and the reserved hole; detecting the mechanical vias on the substrate to be drilled to obtain the position of the mechanical vias; and determining the position of the reserved hole based on the position and positional relationship of the mechanical vias.

[0110] Specifically, mechanical vias can be pre-machined on the circuit layer. The positional relationship between these mechanical vias and the pre-drilled holes on the ceramic layer can be established during the lamination process: during lamination, the mechanical vias on the circuit layer (as fixed references) and the pre-drilled holes on the ceramic layer (as target features) are simultaneously captured, and the vector offset of each pre-drilled hole relative to the adjacent mechanical vias is recorded using image recognition or X-ray fluoroscopy. This offset is stored in the CNC system as a coordinate mapping parameter for subsequent processing. After lamination, by detecting the mechanical vias on the substrate to be drilled, the actual coordinates of these mechanical vias are captured. Based on the actual coordinates of the mechanical vias and the pre-stored positional relationship (offset), the actual coordinates of each pre-drilled hole can be calculated, thus obtaining the hole position.

[0111] To improve the cleanliness of subsequent cross-layer interconnect structures, after the cross-layer hole structure is processed, plasma cleaning or chemical desmearing processes (such as potassium permanganate solution) can be used to remove residual organic glue residue on the hole walls and orifices. Then, the substrate surface is slightly smoothed by belt grinding or ceramic brushing machine to remove tiny burrs or glue residue protrusions caused by drilling and extrusion, ensuring the flatness of the CoWoP package.

[0112] It should be noted that, for the sake of simplicity, the aforementioned method embodiments are described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because based on this application, some steps can be performed in other orders.

[0113] like Figure 9 The diagram shown is a schematic of a controller provided in an embodiment of this application. Specifically, the controller 30 may include: a processor 300, a memory 301, and a computer program 302 stored in the memory 301 and executable on the processor 300, such as a processing program. When the processor 300 executes the computer program 302, it implements the steps in the various processing method embodiments described above, for example... Figure 1 The steps S101 to S102 are shown.

[0114] A computer program can be divided into one or more modules / units. One or more modules / units are stored in memory 301 and executed by processor 300 to complete this application. One or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the controller.

[0115] The controller may include, but is not limited to, processor 300 and memory 301. Those skilled in the art will understand that... Figure 9 This is merely an example of a controller and does not constitute a limitation on the controller. It may include more or fewer components than shown, or combine certain components, or different components. For example, a controller may also include input / output devices, network access devices, buses, etc.

[0116] The processor 300 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0117] The memory 301 can be an internal storage unit of the controller, such as the controller's hard drive or RAM. The memory 301 can also be an external storage device of the controller, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 301 can include both internal and external storage units. The memory 301 is used to store computer programs and other programs and data required by the controller. The memory 301 can also be used to temporarily store data that has been output or will be output.

[0118] It should be noted that, for the sake of convenience and brevity, the structure of the controller described above can also be referred to the specific description of the structure in the method embodiment, which will not be repeated here.

[0119] Specifically, Figure 10 This application also provides a drilling apparatus 1, comprising: The processing platform 10 is used to place and fix the substrate to be drilled. The substrate to be drilled is formed by laminating a circuit layer and a ceramic layer with pre-reserved holes. Drilling device 20 includes a spindle and a drill bit disposed on the spindle; The controller 30, connected to the drilling device 20, controls the drilling device 20 to remove material along the depth direction of the reserved hole on the substrate to be drilled according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. The preset processing strategy includes at least mechanical drilling, where the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the reserved hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the reserved hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

[0120] In some embodiments of this application, the spindle can move along the depth direction of the substrate to be drilled, driving the drill bit to move toward the substrate to remove material along the depth direction of the pre-drilled hole.

[0121] In some embodiments of this application, the drilling apparatus 1 may also include a laser, the laser and the drill bit may be coaxially designed, and the laser may be used to guide the laser beam to the substrate to be drilled when the preset processing strategy includes laser processing.

[0122] In some embodiments of this application, the drilling apparatus 1 may further include a target gripping device, which may be a combination of a thermal excitation device and an infrared sensor, a detection probe, a scanning device, or a mechanical target gripping device. As mentioned above, the combination of the thermal excitation device and the infrared sensor can be used to acquire the transient thermal field distribution on the surface of the substrate to be drilled, so that the controller 30 can extract the geometric center of the thermal anomaly region. The detection probe can be used to scan the surface of the substrate to be drilled and acquire electromagnetic response signals, so that the controller 30 can determine the extreme points of the electromagnetic response signals. The scanning device can be used to acquire images, so that the controller 30 can detect the position of the micro-morphology on the surface of the substrate to be drilled based on the images. The mechanical target gripping device can be used to detect the mechanical through holes on the substrate to be drilled and obtain the position of the mechanical through holes, so that the controller 30 can determine the position of the reserved hole based on the position and positional relationship of the mechanical through holes.

[0123] It is understood that the drilling equipment 1 may also be equipped with other components such as peripherals and power supplies, and this application does not impose any restrictions on this.

[0124] It should be noted that the drilling equipment 1 can be used to implement this application. Figures 1 to 8 The processing method shown can be implemented, for example, by the cooperation of the controller 30 and the target grabbing device to achieve operations such as target grabbing. The specific implementation methods can be referred to the description of the method embodiment, which will not be repeated in this application.

[0125] like Figure 11As shown, this application also provides a processing system, including: Pre-drilled hole processing equipment 2 is used to process pre-drilled holes in the ceramic layer; The lamination equipment 3 is used to laminate the ceramic layer and the circuit layer with pre-drilled holes to obtain the substrate to be drilled; Drilling equipment 1 is used to remove material along the depth direction of a pre-drilled hole on a substrate to be drilled according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. The preset processing strategy includes at least mechanical drilling, where the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the pre-drilled hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the pre-drilled hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

[0126] For structural details of drilling equipment 1, please refer to Figure 10 The description of this is not repeated here.

[0127] The pre-drilled hole processing equipment 2 can be a laser processing equipment or a wet etching equipment, and this application does not limit it.

[0128] The laser processing equipment may include a laser processing unit and an image positioning unit. The laser processing unit may consist of a laser, a beam expander, a scanning galvanometer, and a telecentric field mirror, used to perform fine ablation on the ceramic layer to form pre-drilled holes. The image positioning unit may be a high-resolution CCD camera and an image processing module connected to it, used to grasp a pre-set target on the ceramic layer before processing.

[0129] The wet etching equipment may include a coating unit, an exposure unit, a developing unit, an etching unit, a stripping unit, and a transfer unit. The coating unit is used to uniformly coat the ceramic layer surface with a dry film. The exposure unit is a projection lithography machine or a proximity lithography machine, which includes an ultraviolet light source. The developing unit, etching unit, and stripping unit are all horizontal conveyor spray structures, each including an independent chemical tank, a circulating filtration system, a spray arm, and a heating and temperature control module. The developing unit uses a sodium carbonate solution to remove the dry film in the exposed area to create windows; the etching unit uses a hydrofluoric acid-based or phosphoric acid-based etching solution to perform isotropic or anisotropic etching on the ceramic in the windowed area through a spray method to form pre-reserved holes; the stripping unit uses a sodium hydroxide solution to peel off the residual dry film.

[0130] The laminating equipment 3 can be a vacuum laminator, including an upper pressure plate, a lower pressure plate, a vacuum chamber, a heating system, and an alignment system. The upper and lower pressure plates can be made of high-rigidity steel plates (thickness ≥ 30mm) with mirror-polished surfaces, used to apply uniform pressure to the stacked ceramic and circuit layers. The heating system includes electric heating rods and heat-conducting oil circulation channels built into the pressure plates, working with temperature sensors to achieve independent temperature control in different zones. The vacuum chamber is connected to a vacuum pump unit to expel interlayer air and prevent air bubbles from remaining before lamination. The alignment system includes a camera located above the chamber (for gripping pre-drilled holes or special targets in the ceramic layer from above) and a camera located below the chamber (for gripping mechanical through-holes in the circuit layer). The two cameras can work together to calculate interlayer offset, precisely aligning the ceramic and circuit layers before lamination.

[0131] Similarly, the machining system can be used to implement this application. Figures 1 to 8 The processing method shown can be specifically implemented by referring to the description of the method embodiment, and will not be elaborated here.

[0132] Furthermore, this application also provides a hybrid substrate including a cross-layer interconnect structure. The cross-layer interconnect structure is obtained by metallizing a cross-layer via structure. The cross-layer via structure is obtained by the processing method provided in this application or by processing based on the processing system provided in this application.

[0133] As mentioned above, the hybrid substrate can be used as the power layer of the circuit board in CoWoP packaging. The circuit board surface is provided with chips, and the cross-layer interconnection structure is used to electrically connect the pads of the chips with the circuit layers in the hybrid substrate, thereby providing functions such as transmission, heat dissipation, and protection for chip products.

[0134] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0135] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0136] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for various specific applications, but such implementations should not be considered beyond the scope of this application.

[0137] In the embodiments provided in this application, it should be understood that the disclosed devices / controllers / systems and methods can be implemented in other ways. For example, the device / controller / system embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0138] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected based on actual needs to achieve the purpose of this embodiment.

[0139] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0140] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed based on the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, based on legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0141] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A processing method, characterized in that, include: The substrate to be drilled is placed on the processing platform. The substrate to be drilled is formed by laminating a circuit layer and a ceramic layer with pre-reserved holes. On the substrate to be drilled, material is removed along the depth direction of the reserved hole according to a preset processing strategy until a cross-layer hole structure is formed through the ceramic layer and the circuit layer. The preset processing strategy includes at least mechanical drilling, where the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the reserved hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the reserved hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

2. The processing method according to claim 1, characterized in that, The reserved hole is obtained by laser processing the ceramic layer according to the preset second laser processing parameters; Alternatively, the reserved hole is formed by opening a window at the hole position of the reserved hole through exposure and development after the dry film is covered on the surface of the ceramic layer, and etching the material in the windowed area.

3. The processing method according to claim 1, characterized in that, The preset processing strategy further includes: performing vibratory drilling along the depth direction using mechanical drilling, wherein the axial vibration frequency of the drill bit is greater than a preset frequency.

4. The processing method according to claim 1, characterized in that, The substrate to be drilled is formed by stacking and laminating the circuit layer and the ceramic layer in a preset layer sequence, wherein the ceramic layer is located in the middle layer and / or the surface layer of the substrate to be drilled after lamination.

5. The processing method according to claim 1, characterized in that, The reserved hole has a first hole diameter, which is less than or equal to the target hole diameter of the cross-layer hole structure. The mechanical drilling is used to remove the material of the circuit layer and trim the hole wall of the reserved hole. Alternatively, the first aperture is larger than the target aperture of the cross-layer hole structure, and the mechanical drilling is used to remove material from the circuit layer.

6. The processing method according to any one of claims 1-5, characterized in that, Before removing material along the depth direction of the pre-drilled hole on the substrate to be drilled, according to a preset processing strategy, until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed, the process further includes: The substrate to be drilled is subjected to a target gripping process to determine the location of the reserved hole.

7. The processing method according to claim 6, characterized in that, The step of gripping the substrate to be drilled to determine the location of the reserved hole includes: Thermal excitation is applied to the surface of the substrate to be drilled, and the transient thermal field distribution on the surface of the substrate to be drilled is acquired by an infrared sensor; Based on the transient thermal field distribution on the surface of the substrate to be drilled, the geometric center of the thermal anomaly region in the substrate to be drilled is extracted, and the position of the reserved hole is determined based on the geometric center.

8. The processing method according to claim 6, characterized in that, The reserved hole has a conductive structure formed by local metallization. The step of gripping the substrate to be drilled to determine the location of the reserved hole includes: The surface of the substrate to be drilled is scanned by a detection probe to determine the extreme points of the electromagnetic response signal, which is generated by the conductive structure. The location of the reserved hole is determined based on the extreme points of the electromagnetic response signal.

9. The processing method according to claim 6, characterized in that, The associated position of the reserved hole has a processing mark with a preset shape, and the processing mark forms a micro-morphology on the surface of the substrate to be drilled during the pressing process; The step of gripping the substrate to be drilled to determine the location of the reserved hole includes: The position of the micro-morphology on the surface of the substrate to be drilled is detected, and the position of the reserved hole is determined based on the position of the micro-morphology.

10. The processing method according to claim 6, characterized in that, The step of gripping the substrate to be drilled to determine the location of the reserved hole includes: Obtain the positional relationship between the pre-machined mechanical vias and the reserved holes on the circuit layer; The mechanical through-holes on the substrate to be drilled are detected to obtain the positions of the mechanical through-holes; Based on the position of the mechanical through hole and the positional relationship, the position of the reserved hole is determined.

11. The processing method according to any one of claims 1-5, characterized in that, The mechanical drilling process also includes: When the distance between the drill bit and the ceramic layer is less than a preset distance, the drill bit is controlled to move along the depth direction according to the preset feed amount, and the radial force of the drill bit is collected in real time. The offset of the drill bit from the center of the reserved hole is detected based on the radial force. The position of the drill bit is adjusted according to the drill bit offset.

12. The processing method according to any one of claims 1-5, characterized in that, The actual machining coordinates of the reserved hole are obtained by correcting the theoretical machining coordinates of the reserved hole based on the pressing offset, wherein the pressing offset is determined based on the pressing deformation field of the hybrid substrate.

13. The processing method according to any one of claims 1-5, characterized in that, Before pressing, the reserved hole is filled with an insulating anti-plating material, which is used to reduce impurities adhering to the hole wall of the ceramic layer during the mechanical drilling process. After forming the trans-layer hole structure penetrating the ceramic layer and the circuit layer, the method further includes removing the insulating anti-plating material.

14. The processing method according to any one of claims 1-5, characterized in that, The cross-layer hole structure is either a through hole or a blind hole.

15. A drilling device, characterized in that, include: A processing platform is used to place and fix a substrate to be drilled, the substrate being formed by laminating a circuit layer and a ceramic layer with pre-drilled holes; A drilling device, including a spindle and a drill bit disposed on the spindle; A controller, connected to a drilling device, controls the drilling device to remove material along the depth direction of the pre-drilled hole on the substrate to be drilled according to a preset processing strategy until a cross-layer hole structure is formed through the ceramic layer and the circuit layer. The preset processing strategy includes at least mechanical drilling, wherein the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the pre-drilled hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the pre-drilled hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

16. A processing system, characterized in that, include: Pre-drilled hole processing equipment, used to process pre-drilled holes in ceramic layers; A lamination device is used to laminate the ceramic layer and the circuit layer with the reserved holes to obtain a substrate to be drilled; The drilling apparatus of claim 15 is used to remove material along the depth direction of the reserved hole on the substrate to be drilled according to a preset processing strategy until a cross-layer hole structure penetrating the ceramic layer and the circuit layer is formed. The preset processing strategy includes at least mechanical drilling, wherein the drill bit of the mechanical drilling is greater than or equal to the target hole diameter. When the reserved hole is a through hole, the preset processing strategy is to perform mechanical drilling according to preset first mechanical processing parameters. When the reserved hole is a blind hole, the preset processing strategy includes: removing material along the depth direction by laser processing according to preset first laser processing parameters, and then drilling along the depth direction by mechanical drilling according to preset second mechanical processing parameters.

17. A hybrid substrate, characterized in that, It includes a cross-layer interconnection structure, which is obtained by metallizing a cross-layer hole structure, and the cross-layer hole structure is obtained by processing based on the processing method of any one of claims 1-14, the drilling equipment of claim 15, or the processing system of claim 16.

18. The hybrid substrate according to claim 17, characterized in that, The hybrid substrate is used as the power layer of the circuit board in the CoWoP package. A chip is disposed on the surface of the circuit board, and the cross-layer connection structure is used to electrically connect the pads of the chip to the circuit layer in the hybrid substrate.

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