Packaging method and packaging structure of a car-grade chip

Abstract

The present application relates to the technical field of chip packaging technology, and provides a packaging method and a packaging structure of a vehicle-grade chip, comprising the following steps: S1: preparing a core plate and a power module, preparing a third wiring layer and a fourth wiring layer on the core plate, processing a first through groove on a first semi-finished product plate, and mounting the power module into the first through groove; the power module comprises a chip and a heat dissipation copper base, and the chip is arranged on the heat dissipation copper base; S2: preparing a second wiring layer and a fifth wiring layer; S3: preparing a copper block; processing a second through groove on a second semi-finished product plate outside the first through groove, and mounting the copper block into the second through groove; S4: preparing a first wiring layer and a sixth wiring layer; and the first wiring layer is in heat conduction connection with the power module and the copper block respectively, and / or the sixth wiring layer is in heat conduction connection with the power module and the copper block respectively.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chip packaging technology, and more particularly to a packaging method and structure of an automotive-grade chip. BACKGROUND

[0002] Vehicle-mounted power chips are increasingly widely used. As users' demand for the computing speed of vehicle-mounted power chips gradually increases, the computing power of vehicle-mounted power chips is also increasingly strong. During the running of a vehicle-mounted power chip, if the temperature is too high, the computing performance will be seriously affected. The existing automotive-grade functional chip usually sets the chip on a heat dissipation copper base to form a power module for heat dissipation. The heat dissipation copper base usually has a concave cavity, and the chip is fixed on the inner wall of the concave cavity. After the chip and the heat dissipation copper base are packaged together, sometimes it is difficult for the heat to be transferred to the external space. As the heat of the chip itself gradually accumulates, the ambient temperature of the chip gradually increases, which seriously affects the normal operation of the chip.

[0003] The existing chip packaging method can refer to the chip packaging method of L1 to L6 in (Chinese invention patent; publication number: CN118763009A; subject name: packaging method and structure of automotive-grade chip; publication date: October 11, 2024). Among them, the L1 layer corresponds to the first wiring layer in the present application, the L2 layer corresponds to the second wiring layer in the present application, the L3 layer corresponds to the third wiring layer in the present application, the L4 layer corresponds to the fourth wiring layer in the present application, the L5 layer corresponds to the fifth wiring layer in the present application, and the L6 layer corresponds to the sixth wiring layer in the present application.

[0004] The existing chip packaging method can refer to the chip packaging method of L1 to L6 in (Chinese invention patent; publication number: CN115841959A; subject name: packaging structure and method of high-power chip; publication date: March 24, 2023). Among them, the L1 layer corresponds to the first wiring layer in the present application, the L2 layer corresponds to the second wiring layer in the present application, the L3 layer corresponds to the third wiring layer in the present application, the L4 layer corresponds to the fourth wiring layer in the present application, the L5 layer corresponds to the fifth wiring layer in the present application, and the L6 layer corresponds to the sixth wiring layer in the present application. SUMMARY

[0005] The purpose of the present application is to provide a packaging method of an automotive-grade chip to solve the technical problem that the heat of the chip itself gradually accumulates and is difficult to be transferred to the external space in the prior art.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is to provide a packaging method of an automotive-grade chip, which comprises:

[0007] S1: preparing a core plate and a power module, preparing a third wiring layer and a fourth wiring layer on the core plate, processing a first through slot in a first semi-finished plate and mounting the power module into the first through slot; the power module comprises a chip and a heat dissipation copper base, and the chip is arranged on the heat dissipation copper base;

[0008] S2: preparing a second wiring layer and a fifth wiring layer;

[0009] S3: preparing a copper block, processing a second through slot in a second semi-finished plate outside the first through slot and mounting the copper block into the second through slot;

[0010] S4: preparing a first wiring layer and a sixth wiring layer; and the first wiring layer is in thermal conductive connection with the power module and the copper block respectively, and / or the sixth wiring layer is in thermal conductive connection with the power module and the copper block respectively.

[0011] Further, the step S1 comprises:

[0012] S11: performing surface treatment on an upper surface of the core plate to form a third wiring layer, performing surface treatment on a lower surface of the core plate to form a fourth wiring layer, processing the first through slot in the core plate after the surface treatment and performing a brown oxidation treatment;

[0013] S12: pasting a first adhesive tape on a surface of the fourth wiring layer and pasting the power module into the first through slot.

[0014] Further, the step S2 comprises:

[0015] S21: performing plasma treatment on the third wiring layer and the fourth wiring layer, sequentially stacking multiple layers of semi-solidified resin sheets and a layer of copper foil on a surface of the third wiring layer and pressing to form a second wiring layer, and after the resin is heated and melted and fills a gap between the power module and an inner wall of the first through slot, performing solidification;

[0016] S22: removing the first adhesive tape on the surface of the fourth wiring layer and performing a supplementary brown oxidation treatment on a surface of the heat dissipation copper base close to the fourth wiring layer;

[0017] S23: sequentially stacking multiple layers of semi-solidified resin sheets and a layer of copper foil on a surface of the fourth wiring layer and pressing to form the fifth wiring layer.

[0018] Further, the step S3 "processing a second through slot in a second semi-finished plate outside the first through slot and mounting the copper block into the second through slot" comprises:

[0019] S31: forming the second through slot in the second semi-finished plate outside the first through slot and mounting the copper block into the second through slot.

[0020] Further, the step S31 comprises:

[0021] S311: making a pattern transfer on the second semi-finished plate; etching away the copper foil above the first copper pillar position for subsequent installation of L2-chip, L2-L3 and L5-L4 to form a first etching window; etching away the copper foil above the copper block position to form a second etching window, wherein the second etching window is larger than the copper block on one side;

[0022] S312: using an automatic optical alignment milling machine to process a second through slot on the second semi-finished plate, wherein the second through slot is larger than the copper block on one side;

[0023] S313: surface mounting a high-temperature second adhesive tape on the fifth wiring layer;

[0024] S314: placing the copper block in the second through slot;

[0025] S315: making a selective hole plugging film, wherein the range of 100 μm from the outer edge of the copper block is set as an opaque area, and the rest of the whole plate area is set as a transparent area;

[0026] S316: making a selective hole plugging screen plate using the film made in step S315, wherein the range of 100 μm from the outer edge of the copper block is set as an oiling area, and the rest of the area is set as an oil blocking area;

[0027] S317: selectively vacuum plugging resin on the second semi-finished plate, filling the gap between the copper block and the second through slot on the second semi-finished plate with hole plugging resin, and then baking at 180°C for 1 hour to completely cure the resin;

[0028] S318: tearing off the high-temperature second adhesive tape on the surface of the fifth wiring layer, and grinding the second wiring layer and / or the fifth wiring layer surface to remove the excess protruding resin.

[0029] Further, the first etching window is circular; and the second etching window is L-shaped or T-shaped.

[0030] Further, the number of copper blocks is three, and the number of second through slots is three; one-to-one correspondence exists between the three copper blocks and the three second through slots; two of the copper blocks are L-shaped, and one of the copper blocks is T-shaped.

[0031] Further, the number of power modules is 12, and the number of first through slots is 12; one-to-one correspondence exists between the 12 power modules and the 12 first through slots.

[0032] Further, the second etching window is 150 μm larger than the single side of the copper block.

[0033] Further, the second through slot is 60 μm larger than the single side of the copper block.

[0034] Further, the step S4 comprises:

[0035] S41: processing a first blind hole between the second wiring layer and the third wiring layer and between the fifth wiring layer and the fourth wiring layer on the inner side of the first etching window, and filling the first copper column in the first blind hole in thermal connection with the power module;

[0036] S42: performing a brown oxidation treatment on the surface treated second wiring layer, the fifth wiring layer and the sidewall of the second semi-finished plate;

[0037] S43: only retaining the brown film of the sidewall of the second semi-finished plate;

[0038] S44: filling the surface circuit spacing of the fifth wiring layer with resin;

[0039] S45: performing two-stage baking on the second semi-finished plate.

[0040] Further, the diameter of the first copper column is 230 μm.

[0041] Further, the step S41 comprises:

[0042] S411: laser drilling the second semi-finished plate, and using a laser drill to process the first blind hole on the copper surface and the chip position of the embedded power module;

[0043] S412: passing the second semi-finished plate through a glue removal line to remove the drill dirt in the first blind hole, and roughening the exposed plug resin surface;

[0044] S413: electroplating the second semi-finished plate to fill the first blind hole, form the first copper column, and connect the L2 / 5 layer copper skin and the copper block.

[0045] Further, the diameter of the first blind hole is 230 μm.

[0046] Further, the first blind hole is formed by superimposing a plurality of sub-blind holes with a diameter of 60 μm.

[0047] Further, the sub-blind holes in the same circle are superimposed by 40%, and the sub-blind holes in adjacent circles are superimposed by 25%.

[0048] Further, the step S4 of preparing the first wiring layer and the sixth wiring layer comprises:

[0049] S46, the second wiring layer and the fifth wiring layer are subjected to plasma treatment, the surface of the second wiring layer is laminated with a plurality of layers of a semi-cured resin sheet and a layer of copper foil, and is pressed to form a first wiring layer; a single-sided copper-coated high-thermal-conductivity insulating film is arranged on the surface of the fifth wiring layer, and is pressed to form the sixth wiring layer;

[0050] S47, a second blind hole is processed between the first wiring layer and the second wiring layer, the second blind hole is filled with copper by electroplating to form the second copper column, the first wiring layer and the sixth wiring layer are subjected to surface treatment to form a third semi-finished product; the third semi-finished product is processed to form a finished product.

[0051] Further, the diameter of the first copper column and / or the second copper column is 230 μm; the center distance between adjacent first copper columns or adjacent second copper columns is 350 μm.

[0052] Further, the thickness-diameter ratio of the first blind hole and / or the second blind hole is less than 1.

[0053] Further, it further comprises: a heat sink; the heat sink is in thermal conductive connection with the sixth wiring layer.

[0054] Further, the heat dissipation copper base has a cavity, the chip is fixed on the inner wall of the cavity through a first sintered silver layer; the chip and the heat sink have a first heat dissipation channel and / or a second heat dissipation channel;

[0055] The elements in the first heat dissipation channel in sequence are: chip, first sintered silver layer, heat dissipation copper base, first copper column on L4 / 5, L5 copper layer, high-thermal-conductivity material layer L5 / 6, L6 copper layer, second sintered silver layer, and heat sink;

[0056] The elements in the second heat dissipation channel in sequence are: chip, first sintered silver layer, heat dissipation copper base, first copper column on L2 / 3, L2 copper layer, copper block, L5 copper layer, high-thermal-conductivity material layer L5 / 6, L6 copper layer, second sintered silver layer, and heat sink.

[0057] Further,

[0058] The thickness of L1-2, L2-3, L4 / 5 and L5-6 layers is 200 μm.

[0059] Further, the distance between adjacent power modules in the X direction and the Y direction is 2 mm; and / or the distance between the power module and the copper block in the X direction and the Y direction is 2 mm.

[0060] Further, the resin in step S317 is a high-heat-resistance hole resin with a Tg value of 170 ℃.

[0061] Further, the plug resin process using vacuum embeds the copper block.

[0062] The application also provides a packaging structure of an automotive-grade chip, comprising a core board, a power module, a copper block, a first wiring layer, a second wiring layer, a third wiring layer, a fourth wiring layer, a fifth wiring layer and a sixth wiring layer.

[0063] The first wiring layer, the second wiring layer, the third wiring layer, the fourth wiring layer, the fifth wiring layer and the sixth wiring layer are respectively arranged on the core board; the first half-finished product board has a first through slot, and the power module is arranged in the first through slot; the power module comprises a chip and a heat-dissipating copper base, and the chip is arranged on the heat-dissipating copper base; the second half-finished product board has a second through slot, and the copper block is arranged in the second through slot; the power module and the copper block are in thermal connection, and / or the sixth wiring layer is in thermal connection with the power module and the copper block respectively.

[0064] The packaging method of the automotive-grade chip has the advantages that: compared with the prior art, the third wiring layer and the fourth wiring layer are prepared on the core board; the first through slot is arranged on the first half-finished product board, and the power module can be positioned and installed after being arranged in the first through slot; the second wiring layer and the fifth wiring layer are prepared, the second through slot is arranged on the second half-finished product board, and the copper block can be positioned and installed after being arranged in the second through slot; the first wiring layer and the sixth wiring layer are prepared, the first wiring layer is in thermal connection with the power module and the copper block respectively, and / or the sixth wiring layer is in thermal connection with the power module and the copper block respectively, so that heat can be transferred between the power module and the copper block, and the heat can be easily dissipated; the power module and the copper block can transfer heat to the outside through the first wiring layer and / or the sixth wiring layer, so that the heat can not be accumulated in the chip. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 The third wiring layer and the fourth wiring layer prepared on the core board are shown in the schematic diagram of the embodiment of the application.

[0066] Figure 2 The first half-finished product board with the first through slot is shown in the schematic diagram of the embodiment of the application.

[0067] Figure 3 The first half-finished product board with the first through slot is shown in the schematic diagram of the embodiment of the application.

[0068] Figure 4 The power module arranged in the first through slot is shown in the schematic diagram of the embodiment of the application.

[0069] Figure 5A schematic diagram for preparing the second wiring layer is provided for the embodiment of the present application;

[0070] Figure 6 A schematic diagram for tearing off the first adhesive tape is provided for the embodiment of the present application;

[0071] Figure 7 A schematic diagram for preparing the fifth wiring layer is provided for the embodiment of the present application;

[0072] Figure 8 A schematic diagram for removing part of the copper foil is provided for the embodiment of the present application;

[0073] Figure 9 A schematic diagram for pasting the second adhesive tape is provided for the embodiment of the present application;

[0074] Figure 10 A schematic diagram for filling the second through slot and tearing off the second adhesive tape is provided for the embodiment of the present application;

[0075] Figure 11 A schematic diagram for opening the first blind hole is provided for the embodiment of the present application;

[0076] Figure 12 A schematic diagram for electroplating is provided for the embodiment of the present application;

[0077] Figure 13 A schematic diagram for preparing the first wiring layer and the sixth wiring layer and installing the heat sink is provided for the embodiment of the present application (the arrow in the figure is the heat flow direction);

[0078] Figure 14 A flowchart of the packaging of the automotive-grade chip is provided for the embodiment of the present application;

[0079] Figure 15 A schematic diagram of the packaging structure of the automotive-grade chip is provided for the embodiment of the present application;

[0080] Figure 16 A schematic diagram for superimposing the sub-blind hole into the first blind hole is provided for the embodiment of the present application.

[0081] In the figure, various reference signs are:

[0082] 1 - core plate; 11 - first through slot; 12 - second through slot; 21 - power module; 21 - heat dissipation copper base; 22 - chip; 31 - first wiring layer; 31a - copper foil of first wiring layer; 31b - dielectric layer of first wiring layer; 32 - second wiring layer; 32a - copper foil of second wiring layer; 32b - dielectric layer of second wiring layer; 33 - third wiring layer; 34 - fourth wiring layer; 35 - fifth wiring layer; 35a - copper foil of fifth wiring layer; 35b - dielectric layer of fifth wiring layer; 36 - sixth wiring layer; 36a - copper foil of sixth wiring layer; 36b - dielectric layer of sixth wiring layer; 41 - first blind hole; 411 - sub blind hole; 42 - second blind hole; 43 - first copper column; 44 - second copper column; 45 - copper block; 51 - first adhesive tape; 52 - second adhesive tape; 53 - first sintered silver layer; 54 - second sintered silver layer; 55 - heat sink. DETAILED DESCRIPTION

[0083] It should be noted that the specific examples are only used to explain the present application, and not used to limit the present application.

[0084] It should be noted that, in the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in this paper is only a description of the relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent: A alone, A and B exist together, and B alone. Three cases. Wherein, A, B can be singular or plural.

[0085] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" or "connected to" another element, it can be directly connected to another element or indirectly connected to another element. When an element is referred to as "fixed to" or "provided on" another element, it can be directly on the other element or indirectly on the other element.

[0086] It should be noted that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0087] It should be noted that the terms "first", "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more of the features.

[0088] It should be noted that the term "a plurality" means two or more, unless otherwise expressly and specifically limited.

[0089] Please refer to Figures 1 to 16 The packaging method of the automotive-grade chip provided by the application will be described. The packaging method of the automotive-grade chip comprises the following steps: S1: preparing a core plate 1 and a power module 2, preparing a third wiring layer 33 and a fourth wiring layer 34 on the core plate 1; processing a first through slot 11 on a first semi-finished plate and mounting the power module 2 into the first through slot 11; the power module 2 comprises a chip 22 and a heat dissipation copper base 21, and the chip 22 is arranged on the heat dissipation copper base 21; S2: preparing a second wiring layer 32 and a fifth wiring layer 35; S3: preparing a copper block 45; processing a second through slot 12 on a second semi-finished plate outside the first through slot 11 and mounting the copper block 45 into the second through slot 12; S4: preparing a first wiring layer 31 and a sixth wiring layer 36; and the first wiring layer 31 is in thermal conductive connection with the power module 2 and the copper block 45 respectively, and / or the sixth wiring layer 36 is in thermal conductive connection with the power module 2 and the copper block 45 respectively.

[0090] In this way, the third wiring layer 33 and the fourth wiring layer 34 are prepared on the core plate 1; the first through slot 11 is formed on the first semi-finished plate, and the installation and positioning of the power module 2 can be realized after the power module 2 is mounted into the first through slot 11; the second wiring layer 32 and the fifth wiring layer 35 are prepared, the second through slot 12 is processed on the second semi-finished plate, and the installation and positioning of the copper block 45 can be realized after the copper block 45 is mounted into the second through slot 12; the first wiring layer 31 and the sixth wiring layer 36 are prepared, the first wiring layer 31 is in thermal conductive connection with the power module 2 and the copper block 45 respectively, and / or the sixth wiring layer 36 is in thermal conductive connection with the power module 2 and the copper block 45 respectively, so that heat can be transferred between the power module 2 and the copper block 45, and heat dissipation is facilitated; the power module 2 and the copper block 45 can transfer heat outward through the first wiring layer 31 and / or the sixth wiring layer 36, so as to avoid the accumulation of heat inside the chip 22.

[0091] In one embodiment, the core plate 1 is a substrate used as a "core" layer in the chip 22 packaging process, which is usually a double-sided copper-clad plate, bearing the load and interconnection of the inner circuit, and providing a basis for subsequent power module 2 embedding and heat dissipation channel processing.

[0092] In one embodiment, the first semi-finished plate is the core plate 1 after the preparation of the third wiring layer 33 and the fourth wiring layer 34 is completed. That is, the first semi-finished plate includes the core plate 1, the third wiring layer 33 and the fourth wiring layer 34.

[0093] In one embodiment, the second semi-finished plate is the core plate 1 after the preparation of the second wiring layer 32 and the fifth wiring layer 35 is completed. That is, the second semi-finished plate includes the core plate 1, the third wiring layer 33 and the fourth wiring layer 34, the second wiring layer 32 and the fifth wiring layer 35.

[0094] In one embodiment, the third semi-finished plate is the core plate 1 after the preparation of the first wiring layer 31 and the sixth wiring layer 36 is completed. That is, the third semi-finished plate includes the core plate 1, the first wiring layer 31, the third wiring layer 33 and the fourth wiring layer 34, the second wiring layer 32 and the fifth wiring layer 35 and the sixth wiring layer 36.

[0095] In one embodiment, the first semi-finished plate is the L3 / 4 semi-finished plate.

[0096] In one embodiment, the second semi-finished plate is the L2 / 5 semi-finished plate.

[0097] In one embodiment, the third semi-finished plate is the L1 / 6 semi-finished plate.

[0098] In one embodiment, in this application, "Lx / y semi-finished plate" (or Lx / y, Lx / y layer) means the core plate 1 after the preparation of x layers and y layers is completed.

[0099] In one embodiment, the first through slot 11 is a hole.

[0100] In one embodiment, the second through slot 12 is a hole.

[0101] In one embodiment, the top of the heat dissipation copper base 21 has a concave cavity, and the chip 22 is arranged in the concave cavity.

[0102] In one embodiment, the heat dissipation copper base 21 is a copper piece.

[0103] In one embodiment, the first wiring layer 31, the L1 copper foil 31a, the L1 dielectric layer 31b, the second wiring layer 32, the L2 copper foil 32a, the L2 dielectric layer 32b, the third wiring layer 33, the fourth wiring layer 34, the fifth wiring layer 35, the L5 copper foil 35a, the L5 dielectric layer 35b, the sixth wiring layer 36, the L6 copper foil 36a, and the L6 dielectric layer 36b can refer to (Chinese invention patent; publication number: CN118763009A; subject name: A packaging method and structure of a car-grade chip; publication date: October 11, 2024).

[0104] In one embodiment, the chip 22 is a MOSFET chip 22 or an IGBT chip 22. The full name of the MOSFET chip 22 is "metal-oxide-semiconductor field effect transistor chip 22"; the full name of the IGBT chip 22 is "insulated gate bipolar transistor chip 22".

[0105] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the application, step S1 includes: S11: performing surface treatment on the upper surface of the core plate 1 to form a third wiring layer 33, performing surface treatment on the lower surface of the core plate 1 to form a fourth wiring layer 34, and processing the first through slot 11 and performing a brown oxidation treatment on the surface-treated core plate 1; S12: attaching a first adhesive tape 51 to the surface of the fourth wiring layer 34, and attaching the power module 2 into the first through slot 11. In this way, after the brown oxidation treatment, the high-temperature-resistant first adhesive tape 51 is attached to the surface of the fourth wiring layer 34, and the power module 2 is temporarily fixed into the first through slot 11. The high-temperature-resistant characteristic of the first adhesive tape 51 ensures that the power module 2 will not be micro-displaced in the subsequent high-temperature pressure transmission or composite adhesive film curing process, thereby maintaining the close fitting state in the first through slot 11, so as to ensure the primary adhesion and positioning between the power module 2 and the core plate 1, and provide a reliable prerequisite for subsequent multi-layer lamination and thermal path construction.

[0106] In one embodiment, in the present application, the "brown oxidation treatment" is a chemical roughening process for the copper surface in PCB manufacturing, also known as "brown oxidation" or "brown oxidation". The main purpose is to generate a micron-level brown oxidation film or roughening layer on the copper surface, so as to significantly improve the mechanical engagement and chemical bonding strength between the subsequent adhesive film, semi-cured resin sheet or dry film and the copper surface, thereby ensuring that the layers will not be delaminated or separated during the multi-layer lamination process. In one embodiment, for example: in a specific oxidation solution (commonly used formulas include sodium hypochlorite / sulfite system, sodium nitrite + hydrochloric acid system or imino phosphite, etc.), a trace oxidation reaction occurs on the copper surface to generate a layer of brown copper oxide (Cu2O / CuO) and / or copper hydroxide. At the same time, a small amount of copper is selectively dissolved to form a rough honeycomb or needle-like microstructure.

[0107] Further, please refer to Figures 1 to 16, as a specific embodiment of the packaging method of the automotive-grade chip provided by the application, step S2 comprises: S21: performing plasma treatment on the third wiring layer 33 and the fourth wiring layer 34, and sequentially stacking multiple layers of semi-cured resin sheets and a layer of copper foil on the surface of the third wiring layer 33 and pressing to form the second wiring layer 32; the resin is heated and molten and fills the gap between the power module 2 and the inner wall of the first through groove 11, and then solidifies; S22: removing the first adhesive tape 51 on the surface of the fourth wiring layer 34, and performing supplementary brown oxidation treatment on the surface of the heat dissipation copper base 21 close to the fourth wiring layer 34; S23: sequentially stacking multiple layers of semi-cured resin sheets and a layer of copper foil on the surface of the fourth wiring layer 34 and pressing to form the fifth wiring layer 35.

[0108] In this way, the third wiring layer 33 and the fourth wiring layer 34 are respectively subjected to plasma treatment, which can activate the surface to a rough honeycomb structure before the semi-cured resin sheet and the core plate 1 form the second wiring layer 32 and the fifth wiring layer 35, and generate hydrophilic hydroxyl and carboxyl groups on the surface, so that the subsequently stacked semi-cured resin sheet can obtain higher wettability and permeability at the interface. By stacking and pressing the semi-cured resin sheet and the copper foil, the multiple layers of semi-cured resin sheets and the single layer of copper foil are constructed on the surface of the third wiring layer 33 to form the second wiring layer 32, and this layer structure constructs a dielectric layer and a heat conduction layer composite system with uniform thickness around the power module 2, and the adhesive film is heated and molten during the heating and pressing process and fills the gap between the power module 2 and the core plate 1 after solidification, so that a non-cavity filling effect is formed between the side wall of the power module 2 and the inner wall of the core plate 1, thereby avoiding the high voltage breakdown phenomenon caused by the local thinning of the dielectric layer or the existence of air gap. By removing the first adhesive tape 51 on the surface of the fourth wiring layer 34, and performing supplementary brown oxidation treatment on the surface of the heat dissipation copper base 21 close to the fourth wiring layer 34, the roughening and chemical bonding performance of the surface of the metal substrate are further improved, so that the adhesion strength of the heat dissipation copper base 21 to the semi-cured resin sheet is significantly improved during the subsequent pressing process, reducing the risk of interface failure caused by interlayer debonding or thermal cycle fatigue. Finally, multiple layers of semi-cured resin sheets and copper foils are sequentially stacked on the surface of the fourth wiring layer 34 and pressed to form the fifth wiring layer 35, and this symmetrical layer structure with the second wiring layer 32 constructs a double-channel heat flow diffusion network between the third wiring layer 33 and the fourth wiring layer 34, and provides equal heat flow paths on the upper and lower sides of the power module 2, ensuring that heat can be quickly and uniformly diffused in the multi-layer composite structure, significantly reducing local temperature rise and temperature gradient.

[0109] Further, please refer to Figures 1 to 16As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the step S3 of "processing the second through slot 12 on the outer side of the first through slot 11 of the second half-finished product board and installing the copper block 45 into the second through slot 12" comprises: S31: forming the second through slot 12 through the second half-finished product board on the outer side of the first through slot 11 and installing the copper block 45 into the second through slot 12.

[0110] In this way, it is very convenient to open the second through slot 12, which only needs to pass through the second half-finished product board on the outer side of the first through slot 11.

[0111] Further, referring to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the step S31 comprises: S311: performing pattern transfer on the second half-finished product board; etching away the copper foil above the positions of the L2-chip 22, L2-L3 and L5-L4 for subsequent installation of the first copper column 43 to form a first etching window; etching away the copper foil above the position for setting the copper block 45 to form a second etching window, wherein the second etching window is larger than one side of the copper block 45; S312: processing the second through slot 12 of the second half-finished product board using the milling machine with automatic optical alignment, wherein the second through slot 12 is larger than one side of the copper block 45; S313: attaching the high-temperature second adhesive tape 52 on the surface of the fifth wiring layer 35; S314: placing the copper block 45 in the second through slot 12; S315: making a selective hole plugging film, wherein the range of 100 μm from the outer edge of the copper block 45 is set as an opaque area on the film, and the remaining whole board area is set as a transparent area; S316: making a selective hole plugging screen plate using the film made in the step S315, wherein the range of 100 μm from the outer edge of the copper block 45 is set as an oiling area on the screen plate, and the remaining area is set as an oil blocking area; S317: selectively vacuum plugging resin for the second half-finished product board, filling the gap between the copper block 45 and the second through slot 12 of the second half-finished product board with hole plugging resin, and then baking at 180°C for 1 hour to completely cure the resin; S318: tearing off the high-temperature second adhesive tape 52 on the surface of the fifth wiring layer 35, and grinding the second half-finished product board to grind the excess protruding resin on the surface of the second wiring layer 32 and / or the fifth wiring layer 35.

[0112] In one embodiment, "the second wiring layer 32 to the third wiring layer 33" means the second wiring layer 32 to the third wiring layer 33 (including the second wiring layer 32 and the third wiring layer 33).

[0113] Thus, by performing pattern transfer on the second semi-finished plate and etching away the copper foil above the L2-chip 22, the copper foil between the second wiring layer 32 and the third wiring layer 33, and the copper foil between the fifth wiring layer 35 and the fourth wiring layer 34 to form the first etching opening, and etching away the copper foil above the copper block 45 to form the second etching opening, which is larger than one side of the copper block 45, it is ensured that the copper block 45 can be smoothly inserted during subsequent milling of the second through groove 12, and sufficient gap is provided for the filling of resin between the sidewall of the opening and the edge of the copper block 45. This not only avoids sidewall scratches and local stress concentration caused by tight fit, but also ensures the formation of a multi-dimensional channel between the first etching opening and the second etching opening, which facilitates the uniform escape of gas and volatile substances between interfaces during subsequent resin filling and baking, reduces the generation of voids and bubbles, and enables the complete penetration and dense filling of the micron-level gap between the second semi-finished plate and the copper block 45 by the hole-plugging resin in the vacuum plugging resin process, greatly improving the interfacial bonding strength and reducing the interfacial thermal resistance. In addition, the milling machine for processing the second through groove 12 uses automatic optical alignment, and the optical detection accuracy can reach the micron level. This ensures that the size tolerance of the single side of the through groove being larger than the single side of the copper block 45 can be stably maintained in mass production, making the gap between each copper block 45 and the second through groove 12 uniform and controlled, providing reliable guarantee for the subsequent placement of the copper block 45 in the second through groove 12 and maintaining its positioning. This integrated milling and block insertion process forms multiple-point contact in mechanical support, significantly enhancing the shear resistance and thermal shock resistance of the package under high vibration and thermal cycling conditions. In addition, the high-temperature second adhesive tape 52 attached to the surface of the fifth wiring layer 35 not only protects the surface of the fifth wiring layer 35, preventing debris, impurities, or oxides from contaminating the surface of the fifth wiring layer 35 during milling and copper block 45 insertion, but also allows for precise demarcation and convenient removal of the resin protruding area by tearing off the high-temperature adhesive tape, thereby simplifying the subsequent resin removal and plate flattening processes. In addition, the preparation of a selective hole plugging film and a selective hole plugging screen based on the film provides a micro-area segmentation function for the resin injection and oiling process: setting the 100 μm range from the outer edge of the copper block 45 as the light-shielding area on the film, and the remaining area as the light-transmitting area, so that the resin is only oiled in the target area and effectively blocks the flow of resin in the non-target area; then setting the 100 μm range from the outer edge of the copper block 45 as the oiling area on the screen, and the remaining area as the oil-blocking area, further controlling the coating shape and thickness of the hole-plugging resin, ensuring that the resin only flows into the gap between the second through groove 12 and the copper block 45 in a vacuum environment, without unnecessary accumulation or overflow of resin in the adjacent area, greatly improving the accuracy of interface filling and the utilization rate of resin.In addition, the resin in the plug hole is fully penetrated by vacuum suction, and then cured by baking at 180 DEG C for 1 hour, which not only eliminates the residual gas and volatile components in the resin, prevents volume shrinkage and cracking in the later stage, but also forms a high cross-linking degree of resin network structure after high temperature curing, and forms a chemical and mechanical double combination between the copper block 45 edge and the second semi-finished plate side wall, realizing the long-term reliability and heat fatigue resistance of the packaging structure. In addition, after tearing off the high-temperature adhesive tape on the surface of the fifth wiring layer 35 and grinding the second wiring layer 32 and / or the fifth wiring layer 35 surface to grind the excess resin protruding on the surface, the flatness of the packaging surface is ensured and the subsequent process is smoothly carried out.

[0114] In one embodiment, in this application, regarding "pattern transfer": "pattern transfer" is a series of photolithography processes in printed circuit board (PCB) manufacturing, which accurately transfers the designed circuit pattern from the film (or digital mask) to the surface of the copper clad laminate (CCL) or prepreg layer. The core purpose is to form a photoresist pattern on the substrate which is completely consistent with the circuit design, so as to accurately etch or electroplate the required conductive circuit in the subsequent process.

[0115] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the first etching window is circular; and the second etching window is L-shaped or T-shaped. In this way, the space can be utilized, and the heat distribution and transmission can be facilitated.

[0116] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the number of copper blocks 45 is three, and the number of second through grooves 12 is three; one-to-one correspondence between the three copper blocks 45 and the three second through grooves 12; two copper blocks 45 are L-shaped, and one copper block 45 is T-shaped. In this way, the multiple through holes and the multiple second through grooves 12 can cooperate to disperse stress and heat.

[0117] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the number of power modules 2 is 12 power modules 2, and the number of first through grooves 11 is 12; one-to-one correspondence between the 12 power modules 2 and the 12 first through grooves 11. In this way, the integrated arrangement of multiple power modules 2 can improve the space utilization.

[0118] Further, please refer to Figures 1 to 16As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the second etching window is 150 μm larger than one side of the copper block 45. In this way, the gap of 150 μm allows the formation of a uniform resin or adhesive film filling layer between the sidewall of the copper block 45 and the wall of the second etching window.

[0119] Further, referring to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the second etching window is 150 μm larger than one side of the copper block 45. In this way, the gap of 150 μm allows the formation of a uniform resin or adhesive film filling layer between the sidewall of the copper block 45 and the wall of the second etching window.

[0120] Further, referring to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the step S4 includes: S41: processing a first blind hole 41 between the second wiring layer 32 and the third wiring layer 33 and between the fifth wiring layer 35 and the fourth wiring layer 34 on the inner side of the first etching window, and filling the first copper column 43 which is in thermal connection with the power module 2 in the first blind hole 41; S42: performing a brown oxidation treatment on the second wiring layer 32, the fifth wiring layer 35 and the sidewall of the second semi-finished plate after surface treatment; S43: only retaining the brown oxidation film of the sidewall of the second semi-finished plate; S44: filling the surface circuit spacing of the fifth wiring layer 35 with resin; and S45: performing two-stage baking on the second semi-finished plate.

[0121] In this way, by processing the first blind hole 41 between the second wiring layer 32 and the third wiring layer 33 and between the fifth wiring layer 35 and the fourth wiring layer 34 and filling the first copper column 43 in the first blind hole 41, a straight-through heat conduction column path is formed from the heat dissipation copper base 21 of the power module 2 upward to L1 / the second wiring layer 32 and downward to L5 / the sixth wiring layer 36; after the brown oxidation treatment on the second wiring layer 32, the fifth wiring layer 35 and the sidewall of the second semi-finished plate, only the brown oxidation film of the sidewall of the second semi-finished plate is retained and the brown oxidation film of other areas is removed, and by generating a high-roughness organic complex protective film on the sidewall, the wettability and mechanical engagement force of the sidewall with the adhesive film or epoxy resin are significantly improved; the three of the first copper column 43 heat conduction, the sidewall brown oxidation enhanced combination, and the resin filling and two-stage baking form a tight and efficient thermal-mechanical-electrical composite conduction and combination network, and high thermal conductivity of the packaging structure is achieved.

[0122] Further, referring to Figures 1 to 16As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the diameter of the first copper column 43 is 230 μm. In this way, the diameter of 230 μm not only ensures that the heat conduction cross-sectional area of the copper column is large enough, but also takes into account the material cost and processing difficulty.

[0123] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, step S41 includes: S411: laser drilling of the second semi-finished plate, using a laser drilling machine to process the first blind hole 41 at the position of the copper surface of the embedded power module 2 and the chip 22; S412: removing the glue line of the second semi-finished plate, removing the drill dirt in the first blind hole 41, and roughening the exposed plug hole resin surface; S413: electroplating the second semi-finished plate to fill the first blind hole 41, form the first copper column 43, and connect the L2 / 5 layer of copper skin and copper block 45. In this way, the first blind hole 41 is accurately processed at the position of the copper surface of the embedded power module 2 and the chip 22 of the second semi-finished plate using a laser drilling machine. This laser drilling is through the rapid and local action of high-energy laser beam and copper base and resin composite layer, which not only ensures the positioning accuracy between the power module 2 and the copper block 45, but also avoids the hole wall cracks and interlayer peeling risk caused by traditional mechanical drilling. In addition, the drill dirt in the first blind hole 41 is cleaned by the glue line removal process, and the exposed plug hole resin surface is roughened: the glue line removal process can efficiently remove the organic residues and trace metal splashes generated during laser drilling, and the roughening step forms a micron-level honeycomb-shaped concave-convex microstructure on the resin hole wall. This microstructure significantly improves the wettability and mechanical engagement of the hole wall to the subsequent filling material, greatly enhances the interfacial bonding strength between the blind hole sidewall and the first copper column 43, and effectively suppresses the micro-crack propagation and peeling failure of the hole wall and the filling body under cold and hot cycle and vibration load. In addition, by electroplating the second semi-finished plate as a whole, the first blind hole 41 after the foregoing roughening is filled and the first copper column 43 is formed, and at the same time, the L2 / 5 layer of copper skin and the copper block 45 are connected by means of electrochemical deposition principle.

[0124] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the present application, the diameter of the first blind hole 41 is 230 μm. In this way, 230 μm takes into account the positioning accuracy and processing efficiency. On the other hand, this hole diameter can provide the best deposition environment for the formation of the first copper column 43 during the electroplating hole filling stage.

[0125] Further, please refer to Figures 1 to 16, as a specific embodiment of the packaging method of the automotive-grade chip provided by the application, the first blind hole 41 is formed by stacking a plurality of sub-blind holes 411 with a diameter of 60μm. In this way, the sub-blind holes 411 with a diameter of 60μm are distributed in the copper surface of the power module 2 and the position of the chip 22 in a certain stacking manner, which can effectively reduce the laser drilling energy demand and the heat affected zone range of a single hole; the first blind hole 41 with a larger diameter is formed by processing a plurality of sub-blind holes 411, and the processing precision is higher.

[0126] Further, please refer to Figures 1 to 16 , as a specific embodiment of the packaging method of the automotive-grade chip provided by the application, the sub-blind holes 411 in the same circle are stacked by 40% and the sub-blind holes 411 in adjacent circles are stacked by 25%. In this way, the processing efficiency of the first blind hole 41 is improved.

[0127] In one embodiment, μm is: micrometer.

[0128] Further, please refer to Figures 1 to 16 , as a specific embodiment of the packaging method of the automotive-grade chip provided by the application, the first wiring layer 31 and the sixth wiring layer 36 are prepared in step S4, including: S46, the second wiring layer 32 and the fifth wiring layer 35 are subjected to plasma treatment, the surface of the second wiring layer 32 is stacked with a plurality of layers of semi-solid resin sheets and a layer of copper foil, and the first wiring layer 31 is formed by pressing; a single-sided copper-coated high-thermal-conductivity insulating film is arranged on the surface of the fifth wiring layer 35, and the sixth wiring layer 36 is formed by pressing; S47, the second blind hole 42 is processed between the first wiring layer 31 and the second wiring layer 32, the second blind hole 42 is filled with copper by electroplating to form the second copper column 44, the first wiring layer 31 and the sixth wiring layer 36 are subjected to surface treatment to form a third semi-finished product; the third semi-finished product is processed to form a finished product.

[0129] Thus, the second wiring layer 32 and the fifth wiring layer 35 are subjected to plasma treatment, so that the dielectric resin or copper foil surface of the two layers generates a highly roughened honeycomb structure and is rich in hydrophilic functional groups, effectively improving the bonding strength between the subsequent semi-cured resin sheet and the base layer; the surface of the second wiring layer 32 after plasma treatment is sequentially stacked with multiple layers of semi-cured resin sheets and a layer of copper foil and is pressed to form the first wiring layer 31, which is closely combined with the L1 dielectric layer and the L2 copper foil to ensure reliable electrical connection between the first wiring layer 31 and the lower layer circuit; a single-sided copper-coated high-thermal-conductivity insulating film is arranged on the surface of the fifth wiring layer 35 and is pressed to form the sixth wiring layer 36, which is constructed by the L6 dielectric layer 36B and the L6 copper foil 36A to form a top metal surface layer with excellent thermal conductivity; the second blind hole 42 is processed between the first wiring layer 31 and the second wiring layer 32 and is electroplated to form the second copper column 44, and the surfaces of the first wiring layer 31 and the sixth wiring layer 36 are subjected to surface treatment to form the third semi-finished product plate.

[0130] In one embodiment, the single-sided copper-coated high-thermal-conductivity insulating film please refer to: (Chinese invention patent; publication number: CN118763009A; subject name: a packaging method and structure of a car-grade chip; publication date: October 11, 2024).

[0131] Further, please refer to Figures 1 to 16 , as a specific embodiment of the packaging method of the car-grade chip provided by the present application, the diameter of the first copper column 43 and / or the second copper column 44 is 230μm; the center distance between adjacent first copper columns 43 or adjacent second copper columns 44 is 350μm. Thus, 230μm takes into account the positioning accuracy and processing efficiency. On the other hand, this aperture size can provide the best deposition environment for the formation of the first copper column 43 during the electroplating hole filling stage.

[0132] Further, please refer to Figures 1 to 16 , as a specific embodiment of the packaging method of the car-grade chip provided by the present application, the thickness-to-diameter ratio of the first blind hole 41 and / or the second blind hole 42 is less than 1. Thus, the thickness-to-diameter ratio <1 means that the diameter of the first blind hole 41 and / or the second blind hole 42 is greater than the thickness of the plate layer, which is beneficial to the gravity and flowability of the liquid phase fluid (such as copper electroplating solution, hole filling resin) in the subsequent electroplating or resin filling process, reducing the air stagnation area.

[0133] Further, please refer to Figures 1 to 16 , as a specific embodiment of the packaging method of the car-grade chip provided by the present application, further comprising: a heat sink 55; the heat sink 55 is in thermal contact with the sixth wiring layer 36. Thus, the heat on the sixth wiring layer 36 can be dissipated through the heat sink 55.

[0134] Further, please refer to Figures 1 to 16As a specific embodiment of the packaging method of the vehicle-grade chip provided by the application, the heat dissipation copper base 21 has a cavity, and the chip 22 is fixed on the inner wall of the cavity through the first sintered silver layer 53; the chip 22 and the heat sink 55 have a first heat dissipation channel and / or a second heat dissipation channel; the elements conducting heat on the first heat dissipation channel in turn are: the chip 22, the first sintered silver layer 53, the heat dissipation copper base 21, the first copper column 43 on L4 / 5, the L5 copper layer, the L5 / 6 layer of high thermal conductivity material, the L6 copper layer, the second sintered silver layer 54, and the heat sink 55; the elements conducting heat on the second heat dissipation channel in turn are: the chip 22, the first sintered silver layer 53, the heat dissipation copper base 21, the first copper column 43 on L2 / 3, the L2 copper layer, the copper block 45, the L5 copper layer, the L5 / 6 layer of high thermal conductivity material, the L6 copper layer, the second sintered silver layer 54, and the heat sink 55.

[0135] In this way, the chip 22 can be conveniently cooled externally through the first heat dissipation channel and / or the second heat dissipation channel.

[0136] In one embodiment, the L5 / 6 layer of high thermal conductivity material is: the L5 dielectric layer 35b and the L6 dielectric layer 36b.

[0137] Further, referring to Figures 1 to 16 As a specific embodiment of the packaging method of the vehicle-grade chip provided by the application, the thickness of the L1-2, L2-3, L4 / 5, and L5-6 layers of dielectric is 200 μm. In this way, in an 800V and above vehicle-grade application platform, if the thickness of the dielectric between the layers of the multilayer board is insufficient, creeping or breakdown may occur under high field strength. The dielectric thickness of 200 μm can provide sufficient insulation distance and electrical strength margin, and the interlayer dielectric is not prone to dielectric breakdown or surface creeping failure under high pressure working conditions.

[0138] Further, referring to Figures 1 to 16 As a specific embodiment of the packaging method of the vehicle-grade chip provided by the application, the distance between the adjacent power modules 2 in the X direction and the Y direction is 2 mm; and / or the distance between the power module 2 and the copper block 45 in the X direction and the Y direction is 2 mm. In this way, the safety distance of 2 mm can keep the surface creeping distance compliant under working voltage, preventing short circuit or flashover failure between the power modules 2 or between the power module 2 and the copper block 45 due to static electricity or overvoltage; and the compact arrangement makes the thermal channel distance between the power module 2 and the increased layer copper block 45 uniform.

[0139] Further, referring to Figures 1 to 16As a specific embodiment of the packaging method of the automotive-grade chip provided by the application, the resin in step S317 is a high-heat-resistant via resin with a Tg value of 170 DEG C. In this way, the high-Tg resin not only has excellent thermal stability, but also can maintain moderate flow during short-time high-temperature and high-pressure pressing, so that the resin micro-flow can fill the narrowest through-slot gap, and after solidification, it has a balance of sufficient dielectric strength and thermal conductivity.

[0140] Further, please refer to Figures 1 to 16 As a specific embodiment of the packaging method of the automotive-grade chip provided by the application, the via resin process is embedded into the copper block 45 under vacuum. In this way, the via resin completely penetrates into the gap between the copper block 45 and the wall of the second through slot 12 under the driving of the air pressure difference, and the air or other inert gases are excluded, avoiding the air bubbles and resin cavities commonly seen in the conventional pressure or gravity via process.

[0141] Please refer to Figures 1 to 16 The application further provides a packaging structure of an automotive-grade chip, comprising a core plate, a power module, a copper block, a first wiring layer, a second wiring layer, a third wiring layer, a fourth wiring layer, a fifth wiring layer, and a sixth wiring layer; the first wiring layer, the second wiring layer, the third wiring layer, the fourth wiring layer, the fifth wiring layer, and the sixth wiring layer are arranged on the core plate; the first half-finished plate has a first through slot, and the power module is installed in the first through slot; the power module comprises a chip and a heat-dissipating copper base, and the chip is arranged on the heat-dissipating copper base; the second half-finished plate has a second through slot, and the copper block is installed in the second through slot; the power module and the copper block are in thermal conductive connection, and / or the sixth wiring layer is in thermal conductive connection with the power module and the copper block, respectively.

[0142] In this way, the third wiring layer 33 and the fourth wiring layer 34 are prepared on the core plate 1; the first through slot 11 is formed on the first half-finished plate, and the installation and positioning of the power module 2 can be realized after the power module 2 is installed in the first through slot 11; the second wiring layer 32 and the fifth wiring layer 35 are prepared, the second through slot 12 is processed on the second half-finished plate, and the installation and positioning of the copper block 45 can be realized after the copper block 45 is installed in the second through slot 12; the first wiring layer 31 and the sixth wiring layer 36 are prepared, the first wiring layer 31 is in thermal conductive connection with the power module 2 and the copper block 45, respectively, and / or the sixth wiring layer 36 is in thermal conductive connection with the power module 2 and the copper block 45, respectively, so that heat can be transferred between the power module 2 and the copper block 45, and the heat can be easily dissipated; the power module 2 and the copper block 45 can transfer heat outward through the first wiring layer 31 and / or the sixth wiring layer 36, avoiding the accumulation of heat inside the chip 22.

[0143] Embodiment one: the process flow of the packaging method of the automotive-grade chip is as follows:

[0144]

First processing step

[0145] In this way, the double-sided copper-clad plate with copper thickness of 1.292 mm is selected as the L3 / 4 layer core board substrate, and the copper foils on the upper and lower surfaces of the core board are strictly cleaned and activated to remove surface oxides and oil stains, ensuring the adhesion consistency of the photoresist and the copper surface. Then, the dry film photoresist is uniformly coated on the clean and smooth copper surface, and the mask film carrying the circuit layout pattern is precisely aligned with the photosensitive glue layer by the exposure machine, and the L3 (upper surface) and L4 (lower surface) are respectively irradiated with ultraviolet light. After irradiation, the photoresist in the unexposed area is dissolved and removed using alkaline developer, exposing the copper foil area to be etched, and then the exposed excess copper material is completely dissolved using chemical etching process. Finally, the remaining photoresist is stripped by solvent, and the L3 / 4 inner layer pattern consistent with the designed circuit is obtained.

[0146]

Step 2

[0147] In this way, the first semi-finished plate is loaded into the numerical control milling machine with automatic optical positioning function, and the machine vision recognizes the etched L3 / L4 circuit pattern or special marker on the plate surface to realize self-adaptive correction of the through slot processing coordinates. Then, 12 through slots are processed on the plate material using a milling cutter, and the through slot shape matches the copper-based groove of the power module, with a single side size designed to be 100 μm larger than the single side of the power module to balance the assembly allowance and tightness.

[0148]

Step 3

[0149] In this way, the first semi-finished plate is browned (chemically oxidized), which generates a thin film of organic copper complex on the copper surface. This film is brown in color and has high specific surface area and polarity characteristics. The chemical oxidation reaction enhances the roughness and surface energy of the copper surface, significantly improving the bonding force between the subsequent resin or adhesive film and the copper interface. Then, high-temperature resistant adhesive tape is pasted on the L4 surface to fix the module position during the subsequent installation of the power module and high-temperature pressing process, preventing the module from shifting or falling off. The nanoscale pore structure of the brown film not only promotes the penetration and mechanical locking of the encapsulating resin on the sidewall, but also allows the brown layer to remain on the sidewall after removing the top brown film, achieving a clean top surface of the circuit through optimized grinding process.

[0150]

Step 4

[0151] In this way, the brown film improves the bonding strength of the side wall of the module. Even in the subsequent high-temperature and high-pressure pressure transmission process, the resin can penetrate into the micropores of the brown film, achieve excellent mechanical locking, prevent the module from falling off and interface delamination, and improve the attachment yield. The temporary fixing of the tape ensures the stability of the module position during the attachment stage, effectively avoids micro-movement caused by vibration or thermal stress, and improves the attachment yield. The introduction of high-precision mounting equipment replaces the traditional manual or semi-automatic process, significantly reduces the positioning error, ensures the consistency and flatness of the 12 modules on the same board, and lays a foundation for subsequent high-reliability packaging and mass production.

[0152] 【5th processing step】Please refer to Figures 1 to 16 : Two 1086 prepregs are arranged on the L3 surface, and then a copper foil is arranged to form an L2 / 4 layer structure, and a first pressure transmission (high-temperature compression) is performed. The resin in the prepreg melts and flows into and fills the gap between the power module and the through slot of the L3 / 4 layer core board, and then the resin solidifies to stably embed the power module in the PCB.

[0153] In this way, the resin gradually solidifies after filling the gap to form a composite structure tightly combined with the copper-based side wall, the bottom of the through slot, and the surrounding copper foil, achieving mechanical stable embedding of the power module in the PCB, avoiding the warping and stress concentration problems of traditional surface mounting; the molten and filled resin layer acts as a dielectric insulation and thermal conduction medium, connecting the heat diffusion path of the module and the upper and lower copper layers, effectively reducing the internal thermal resistance of the module, improving the heat dissipation efficiency, and ensuring electrical isolation and flame retardation between layers.

[0154] 【6th processing step】Please refer to Figures 1 to 16 : The high-temperature tape on the L4 surface is torn off.

[0155] In this way, after high-temperature compression and proper curing, the high-temperature tape used for attachment on the L4 surface is torn off to restore the permeability of the through slot and the flatness of the surface for subsequent lamination processes.

[0156] 【7th processing step】: The core board is passed through the brown line again, and the back surface of the heat dissipation copper base is supplemented with brown.

[0157] In this way, the supplementary brown can ensure a more consistent surface and more active surface of the core board. In the subsequent hot pressing process of the prepreg, the resin penetrates deeply and mechanically "engages" through the microporous structure of the brown film, significantly improving the interfacial shear strength and preventing delamination or board explosion of the module under the action of thermal cycling and high-voltage electric field.

[0158]

Step 8

[0159] In this way, the surface of the core board is bombarded by active ions in the plasma, including the filled and cured resin ink and the surface of the brown film. During the bombardment process, the resin surface is etched into a honeycomb micro-rough structure, and a large number of polar functional groups (mainly hydroxyl -OH and carboxyl -COOH) are introduced on the surface, greatly improving the surface energy and hydrophilicity. In addition, after plasma treatment, the micropores and polar groups on the resin surface can better chemically crosslink and physically penetrate the prepreg resin used in subsequent lamination, overcoming the interface incompatibility between different resin systems, reducing the probability of interface voids and micro-cracks.

[0160]

Step 9

[0161] In this way, the double-layer prepreg provides a tight and bubble-free filling layer for the resin; the honeycomb rough pores formed by the molten resin through plasma and the porous network structure of the previous brown film achieve "multi-scale" penetration and locking, further improving the interface bonding strength and long-term heat resistance; the embedding of the copper foil not only provides continuous electrical interconnection and interlayer heat diffusion channels, but also forms a mechanical stress buffer layer in the overall structure, balancing the difference in thermal expansion coefficient and reducing thermal cycle fatigue.

[0162]

Step 10

[0163] In this way, the non-woven brush roller is used to "grind the board" on the L2 surface: by controlling the rotation speed, pressure and movement speed of the brush roller, the flexible fiber structure and moderate grinding force of the non-woven fabric are used to perform a slight mechanical friction on the copper surface, effectively peeling off the top brown film while retaining the side wall brown film to avoid affecting the bite of the side wall resin.

[0164]

Step 11

[0165] Thus, by designing a safety margin of 150 μm, manufacturing tolerances and mechanical processing alignment errors are taken into account, and structural damage in secondary processing is avoided; the material flow and adhesion conditions during subsequent resin and electroplating hole filling are optimized, ensuring the resin / copper bonding strength of the blind hole and the heat dissipation window area and the smoothness of the heat dissipation channel, providing reliable protection for reliable operation under high pressure (≥800 V) and high temperature (≥150 degrees Celsius) conditions.

[0166]

Step 12

[0167]

Step 13

[0168] In this way, the adhesive tape can help fix the heat dissipation copper block in the 14th processing step.

[0169]

Step 14

[0170] In this way, by using L / T-shaped instead of traditional large-area square blocks, the maximum heat dissipation block embedding can be achieved in a limited PCB area, taking into account the optimal layout between the power module and the heat dissipation block, and improving the overall module density and heat dissipation efficiency.

[0171]

Step 15

[0172] In this way, the light shielding area corresponds to the copper block and its periphery, which can avoid the resin flowing into the heat dissipation channel during the vacuum plug hole of the screen plate, and ensure the dense filling of the resin around the heat dissipation block and in the through groove.

[0173]

Step 16

[0174] Thus, the same screen plate realizes the function of oiling and oil blocking in different areas, without the need for multiple screen changes, significantly improving the screen making efficiency. When the screen plate is used for vacuum plugging or screen printing resin, the resin can be precisely controlled to flow out only in the oiling area to fill the hole, while the resin is completely blocked in the oil blocking area. Through precise selective oiling, resin loss and pollution are reduced, and overflow or accumulation of resin in positions that do not need to be filled is also avoided.

[0175]

Step 17

[0176] Thus, by combining the vacuum-assisted and capillary infiltration mechanisms, the vacuum-plugged resin not only fills the small gap between the copper block and the substrate, providing excellent mechanical support and shear strength, but also maintains long-term thermal cycle reliability through a high Tg value; in addition, uniform resin filling forms a continuous dielectric layer, avoiding local stress concentration and electric field breakdown risks caused by poor filling, ensuring stable operation of the plate body in high voltage (≥800V) and high temperature environments.

[0177]

Step 18

[0178] Thus, the ground surface has higher flatness, providing an ideal reference surface for subsequent inner layer pattern transfer, blind hole drilling, and pressing; on the other hand, removing the protruding resin on the surface avoids subsequent layer alignment deviation and uneven pressure problems, ensuring consistent pressure transmission and bonding effect in downstream processes, significantly improving the overall process yield of multi-layer plates and the consistency of electrical and thermal performance of the final product.

[0179]

Step 19

[0180] Thus, the stacked hole laser forming not only overcomes the problem of limited laser single hole diameter, but also avoids the burr and stress concentration caused by mechanical drilling, ensuring high surface quality and low heat-affected zone of the hole wall. The φ230μm blind hole provides sufficient conductive cross-sectional area, which can maintain low resistance and high reliability in high current applications.

[0181]

Step 20

[0182] After the "glue line" treatment, the resin surface in the blind hole changes from smooth and dense to porous and rough, significantly improving the wettability and mechanical adhesion of the electroplated copper layer.

[0183]

Step 21

[0184] In this way, the main copper skin of the L2 / 5 layer is directly connected to the buried hole copper pillar and the L / T-shaped large copper block in terms of electrical and thermal properties: on the one hand, the copper pillar penetrates the inner layers of L2-3 and L4-5, forming a short-path, high-conductivity current channel; on the other hand, the L / T-shaped large copper block is welded to the L2 / 5 main copper foil through electroplating, forming two rapid heat dissipation paths to guide the module heat to the large-area outer thermal surface.

[0185]

Step 22

[0186]

Step 23

[0187] In this way, the brown film has a nano-porous honeycomb structure, high specific surface area, and polar functional groups (such as -NH, -OH), which can significantly improve the surface energy and wettability.

[0188]

Step 24

[0189] After removing the polar brown film on the top surface, the pure copper surface is restored, improving the wettability and adhesion uniformity of the subsequent photoresist and solder resist ink, ensuring that the outer layer pattern and solder resist pattern have clear and sharp edge boundaries; the retention of the sidewall brown film allows the sidewall of the via, blind hole, and heat sink slot to have high surface energy and mechanical adhesion, which is beneficial for subsequent resin penetration, filling, and interlayer bonding of multi-layer pressing.

[0190]

Step 25

[0191] Thus, the photosensitive glue of the transparent part of the film is cured by ultraviolet exposure, while the glue layer of the opaque part is not cured and is removed by the developing solution, forming a selective plug screen plate with clear distinction between the oil-repellent (open) and oil-repellent (closed) functional areas.

[0192] 【26th processing step】: Use the screen plate, L5 upward, do vacuum plug resin, fill the line spacing of L5 surface.

[0193] Thus, fill all the line spacing and buried hole gap of L5 surface by capillary and pressure. The whole process is automated and bubble-free, and the resin can penetrate deeply and tightly combine with the side wall surface activated by brownification / plasma.

[0194] 【27th processing step】: The second semi-finished plate is baked in two stages, the first stage is 110℃*60min, and the second stage is 150℃*30min. After baking, the resin curing monomer does not completely crosslink and polymerize, ensuring that the resin monomer of the ink can further crosslink and polymerize with the resin monomer of the high heat dissipation material in the high temperature pressing process of the 29th processing step, which helps to improve product reliability.

[0195] 【28th processing step】: L2 / 5 layer is treated by decontamination and plasma, making the resin ink surface roughened into a honeycomb shape, and generating hydrophilic hydroxyl and carboxyl groups on the resin ink surface, improving its adhesion to the subsequent prepreg resin.

[0196] In one embodiment, the drillings and carbides are first completely stripped, and a preliminary rough texture is etched on the resin surface; then, low-pressure plasma treatment is performed, usually in an argon / oxygen mixed atmosphere to excite the plasma, so that active ions bombard the resin ink surface, break the surface polymer chain, form a honeycomb-shaped micro-pore structure, and introduce a large number of hydrophilic functional groups (-OH, -COOH). This combined process of physical micro-roughening and chemical activation can significantly increase the specific surface area and surface energy of the resin pore wall, so that the prepreg resin can penetrate, fill and co-crosslink with the substrate sidewall resin under high temperature and high pressure during subsequent lamination, thereby greatly improving the interlayer adhesion strength and thermal cycle reliability.

[0197] 【29th processing step】: The layer-increasing plate (second semi-finished plate) is browned, then two 1086 prepregs and a copper foil are arranged in L2, and a 200μm high-heat-dissipation material RCC is arranged in L5, to form a L1 / 6 layer structure.

[0198] Thus, the resin in the prepreg and the single-sided copper-clad high-thermal-conductivity insulating adhesive film melts and flows under the action of hot pressing, filling and encapsulating the through slot and the micro gap around the perimeter of the heat dissipation copper block, and then solidifying and forming. The process uses the high surface activity of the brown film to promote mechanical engagement of the resin and the copper foil sidewall, and the high filler content and copper foil layer of the single-sided copper-clad high-thermal-conductivity insulating adhesive film to enhance the heat dissipation performance while providing a stable dielectric connection, ultimately forming an L1 / 6 two-end metal panel structure.

[0199]

Step 30

[0200]

Step 31

[0201] Thus, the φ230μm copper pillar not only provides high current carrying capacity and realizes intra-layer and cross-layer electrical interconnection, but also forms a stable mechanical and electrical bond with the sidewall resin and the copper foil of the L2 / L3 and L4 / fifth wiring layers, significantly improving the electrical conductivity and thermal conductivity efficiency of the board.

[0202]

Step 32

[0203]

Step 33

[0204] In one embodiment, first, a precision screen printer is used to uniformly apply liquid solder mask ink to the surface of the semi-finished plate, and the ink forms a thin film only in the reserved line and pad spacing and via cap area on the board; then, in a visible light exposure machine, the solder mask mask plate is used to UV irradiate the board surface, causing the ink in the light-transmitting area to crosslink and solidify, while the light-shielded area remains soluble; next, the board is immersed in an alkaline developing solution to wash away the unhardened ink, exposing the pads and via caps and leaving the insulation line protection film; finally, post-curing is performed at 100℃-120℃ (30-60min).

[0205]

Step 34

[0206] Thus, the nickel layer acts as a copper-tin diffusion barrier and provides mechanical support; the palladium layer inhibits nickel oxidation, ensures the adhesion of the gold layer, and can serve as a backup solderable surface; the outermost ultra-thin gold layer provides excellent solder wetting and long-term oxidation resistance, ensuring good reflow / peak solder joint formation and preventing solder bloom.

[0207]

Step 35

[0208] Thus, after all plating and surface treatment are completed, the outer layer of the semi-finished product is routed and separated to form units that meet the requirements of the back-end assembly.

[0209] The above description is only preferred embodiments of the present application, and it should be pointed out that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and replacements can be made, and these improvements and replacements should also be considered as the protection scope of the present application.

Claims

1. A method of packaging a car-grade chip, characterized by, Comprising: S1: preparing a core plate and a power module, preparing a third wiring layer and a fourth wiring layer on the core plate to form a first semi-finished product plate; processing a first through slot on the first semi-finished product plate and mounting the power module into the first through slot; the power module comprises: a chip and a heat dissipation copper base, the chip is arranged on the heat dissipation copper base; S2: preparing a second wiring layer and a fifth wiring layer to form a second semi-finished product plate; S3: preparing a copper block; processing a second through slot on the second semi-finished product plate outside the first through slot and mounting the copper block into the second through slot; S4: preparing a first wiring layer and a sixth wiring layer; and the first wiring layer is respectively in thermal conductive connection with the power module and the copper block, and / or the sixth wiring layer is respectively in thermal conductive connection with the power module and the copper block; In the step S3, "processing a second through slot on the second semi-finished product plate outside the first through slot and mounting the copper block into the second through slot", comprising: S31: forming the second through slot through the second semi-finished product plate outside the first through slot, and mounting the copper block into the second through slot; The step S31 comprises: S311: performing pattern transfer on the second semi-finished product plate; etching away copper foils above positions for subsequently mounting first copper columns to form first etching windows; etching away copper foils above positions for arranging the copper block to form second etching windows, wherein the second etching windows are larger than a single side of the copper block; S312: processing the second through slot on the second semi-finished product plate by using a milling machine with automatic optical alignment, the second through slot is larger than a single side of the copper block; S313: attaching a high-temperature second adhesive tape on a surface of the fifth wiring layer; S314: placing the copper block in the second through slot; S315: manufacturing a selective hole-making film, an area within a range of 100 μm from an outer edge of the copper block is set as an opaque area on the film, and a remaining whole plate area is set as a transparent area; S316: manufacturing a selective hole-making screen plate by using the film manufactured in the step S315, an area within a range of 100 μm from the outer edge of the copper block is set as an oiling area on the screen plate, and a remaining area is set as an oil blocking area; S317: selectively vacuum filling resin on the second semi-finished product plate, filling a gap between the copper block and the second through slot on the second semi-finished product plate with hole-making resin, and then baking the resin at 180 DEG C for 1 hour to completely solidify the resin; S318: tearing off the high-temperature second adhesive tape on the surface of the fifth wiring layer, and grinding the second semi-finished product plate to grind away excessive protruding resin on surfaces of the second wiring layer and / or the fifth wiring layer.

2. The method of packaging a chip for automotive applications as claimed in claim 1, wherein, The step S1 comprises: S11: performing surface treatment on an upper surface of the core plate to form a third wiring layer, performing surface treatment on a lower surface of the core plate to form a fourth wiring layer, processing the first through slot on the core plate after the surface treatment, and performing a brown oxidation treatment; S12: attaching a first adhesive tape on a surface of the fourth wiring layer, and attaching the power module into the first through slot.

3. The method of packaging a car-grade chip of claim 2, wherein, The step S2 comprises: S21: performing plasma treatment on the third wiring layer and the fourth wiring layer, and sequentially stacking multiple layers of semi-cured resin sheets and a layer of copper foil on the surface of the third wiring layer and pressing to form the second wiring layer, and after the resin is heated and hot-melted and fills the gap between the power module and the inner wall of the first through slot, solidification is performed; S22: removing the first adhesive tape on the surface of the fourth wiring layer, and performing supplementary brown oxidation treatment on the surface of the heat dissipation copper base close to the fourth wiring layer; S23: sequentially stacking multiple layers of semi-cured resin sheets and a layer of copper foil on the surface of the fourth wiring layer and pressing to form the fifth wiring layer.

4. The packaging method of the automotive-grade chip according to claim 1, wherein the first etching window is circular, and the second etching window is L-shaped or T-shaped.

5. The packaging method of the automotive-grade chip according to claim 4, wherein the number of the copper blocks is three, and the number of the second through slots is three; the three copper blocks and the three second through slots correspond one by one; two of the copper blocks are L-shaped, and one of the copper blocks is T-shaped. The number of the power modules is 12, and the number of the first through slots is 12; the 12 power modules and the 12 first through slots correspond one by one. The second etching window is 150 μm larger than the single side of the copper block.

6. The method of packaging a chip for automotive applications as claimed in claim 1, wherein, The single side of the second through slot is 60 μm larger than the single side of the copper block.

7. The method of packaging a chip for automotive applications as claimed in claim 1, wherein, The step S4 comprises:

8. The method of packaging a chip for automotive applications as claimed in claim 1, wherein, S41: processing a first blind hole between the second wiring layer and the third wiring layer and between the fifth wiring layer and the fourth wiring layer on the inner side of the first etching window, and filling the first blind hole with a first copper column in thermal connection with the power module; 9. The method of packaging a chip for automotive applications as claimed in claim 1, wherein, S42: performing brown oxidation treatment on the surface-treated second wiring layer, the fifth wiring layer, and the sidewall of the second semi-finished plate; S43: only retaining the brown film of the sidewall of the second semi-finished plate; S44: filling the surface circuit spacing of the fifth wiring layer with resin; S45: performing two-stage baking on the second semi-finished plate. The diameter of the first copper column is 230 μm. The step S41 comprises:

10. The method of packaging a chip for automotive applications as claimed in claim 9, wherein, S411: laser drilling the second semi-finished plate to process the first blind hole on the copper surface of the embedded power module and the chip position with a laser drill; 11. The method of packaging a chip for automotive applications as claimed in claim 9, wherein, S412: removing the drill dirt in the first blind hole and roughening the exposed plug resin surface by removing the glue line of the second semi-finished plate; S413: electroplating the second semi-finished plate to fill the first blind hole and form the first copper column, and connecting the copper skin of the second semi-finished plate with the copper block. The diameter of the first blind hole is 230 μm.

13. The packaging method of the automotive-grade chip according to claim 12, wherein the first blind hole is formed by stacking multiple sub-blind holes with a diameter of 60 μm.

12. The method of packaging a chip for automotive applications as claimed in claim 11, wherein, 14. The packaging method of the automotive-grade chip according to claim 13, wherein the sub-blind holes in the same circle are stacked by 40%, and the sub-blind holes in adjacent circles are stacked by 25%. The step S4 comprises: ​ ​ ​ 15. The method of packaging a car-grade chip of claim 9, wherein, ​ S46, the second wiring layer and the fifth wiring layer are subjected to plasma treatment, the surface of the second wiring layer is stacked with a plurality of layers of prepreg and a layer of copper foil, and is pressed to form the first wiring layer; a single-sided copper-clad high-thermal-conductivity insulating film is arranged on the surface of the fifth wiring layer, and is pressed to form the sixth wiring layer; S47, a second blind hole is processed between the first wiring layer and the second wiring layer, the second blind hole is filled with copper by electroplating to form a second copper column, the first wiring layer and the sixth wiring layer are subjected to surface treatment to form a third semi-finished product; the third semi-finished product is processed to form a finished product.

16. The method of packaging a chip for automotive applications as claimed in claim 15, wherein, The diameter of the first copper column and / or the second copper column is 230 μm; the center distance between adjacent first copper columns is 350 μm, and / or the center distance between adjacent second copper columns is 350 μm.

17. The method of packaging a chip for automotive applications as claimed in claim 15, wherein, The thickness-diameter ratio of the first blind hole and / or the second blind hole is less than 1.

18. The packaging method of the automotive-grade chip according to claim 1, further comprising: a heat sink; and the heat sink is in thermal contact with the sixth wiring layer.

19. The packaging method of the automotive-grade chip according to claim 18, wherein the heat sink is a copper base with a cavity, and the chip is fixed on the inner wall of the cavity through a first sintered silver layer; the chip and the heat sink have a first heat dissipation channel and / or a second heat dissipation channel. The elements in the first heat dissipation channel are arranged in sequence as follows: chip, first sintered silver layer, heat dissipation copper base, first copper column on the fourth wiring layer and the fifth wiring layer, copper layer of the fifth wiring layer, high-thermal-conductivity material of the fifth wiring layer and the sixth wiring layer, copper layer of the sixth wiring layer, second sintered silver layer, and heat sink. The elements in the second heat dissipation channel are arranged in sequence as follows: chip, first sintered silver layer, heat dissipation copper base, first copper column on the second wiring layer and the third wiring layer, copper layer of the second wiring layer, copper block, copper layer of the fifth wiring layer, high-thermal-conductivity material of the fifth wiring layer and the sixth wiring layer, copper layer of the sixth wiring layer, second sintered silver layer, and heat sink.

20. The packaging method of the automotive-grade chip according to claim 1, wherein the inter-thickness of the first wiring layer-second wiring layer, the second wiring layer-third wiring layer, the fourth wiring layer-fifth wiring layer, and the fifth wiring layer-sixth wiring layer is 200 μm.

21. The packaging method of the automotive-grade chip according to claim 1, wherein the distance between adjacent power modules in the X direction and the Y direction is 2 mm; and / or the distance between the power module and the copper block in the X direction and the Y direction is 2 mm.

22. The packaging method of the automotive-grade chip according to claim 1, wherein the resin in step S317 is a high-heat-resistant hole resin with a Tg value of 170 ℃.

23. The packaging method of the automotive-grade chip according to claim 22, wherein the hole resin is embedded into the copper block by a vacuum process. ​ ​ ​ ​ ​ ​

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