Chip packaging structure and preparation method thereof

Abstract

The invention provides a chip packaging structure and a preparation method thereof. The chip packaging structure comprises a substrate and a reinforcing sheet, the reinforcing sheet comprises a reinforcing main body which is formed by stacking and reinforcing a plurality of pieces of carbon fiber cloth or a plurality of pieces of carbon fiber composite cloth; the carbon fiber composite cloth is formed by processing carbon fibers and metal fibers; a metal pad is fixedly arranged on the base plate, the reinforcing body is welded to the metal pad, and the plane where the multiple pieces of carbon fiber cloth are located is parallel to the base plate. While the thickness of the reinforcing sheet is reduced, the reinforcing effect of the reinforcing sheet on the substrate is ensured, and the substrate is effectively prevented from warping.

Description

Technical Field

[0001] This invention relates to the field of chip packaging technology, and in particular to a chip packaging structure and its fabrication method. Background Technology

[0002] As chip packaging sizes continue to increase, substrate warpage has become one of the core challenges in chip packaging and integration. Substrate warpage is mainly caused by factors such as the properties of the materials used, thermodynamic effects, and structural design.

[0003] Specifically, substrate warpage refers to the planar deformation of a substrate, such as a PCB, glass substrate, or packaging substrate, due to stress, typically manifesting as bending or twisting. Substrate warpage can lead to problems such as silkscreen deformation, chip misalignment, and poor solder joints. Furthermore, substrate warpage also poses risks to packaging reliability; in specific chip packaging, substrate warpage may cause delamination, cracking, and even affect the reliability of TSVs (Through Silicon Vias) and hybrid bonding. Therefore, how to mitigate substrate warpage during the packaging process has become a crucial issue.

[0004] From a packaging process perspective, the main method to improve substrate warpage currently involves reinforcing the substrate with stiffeners. These stiffeners are bonded to the substrate with adhesive to enhance its resistance to warpage. The primary materials for these stiffeners are metals such as copper and stainless steel. However, as package sizes increase, the stiffeners need to become increasingly thicker to withstand greater warpage.

[0005] However, thicker reinforcing sheets may affect subsequent high-resolution SAT (Scanning Ultrasonic Testing) inspections. Specifically, high-resolution high-frequency ultrasonic probes have relatively short focal lengths, and thicker reinforcing sheets will increase the distance between the high-frequency ultrasonic probe and the substrate, thus making effective SAT inspection impossible. Furthermore, using adhesive as a bonding material to fix the reinforcing sheet will cause it to run at high temperatures and will not effectively prevent substrate warping.

[0006] Therefore, how to reduce the thickness of the reinforcing sheet while ensuring its reinforcing effect on the substrate and effectively preventing substrate warping has become an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned issues, the chip packaging structure and its fabrication method provided by this invention form a reinforcing sheet by stacking and reinforcing multiple carbon fiber cloths or multiple carbon fiber composite cloths into a reinforcing body, which is then welded to the substrate. This approach reduces the thickness of the reinforcing sheet while ensuring its reinforcing effect on the substrate, effectively preventing substrate warping.

[0008] In a first aspect, the present invention provides a chip packaging structure, the chip packaging structure comprising: a substrate and a reinforcing sheet; The reinforcement sheet includes: a reinforcement body formed by stacking and reinforcing multiple carbon fiber cloths or multiple carbon fiber composite cloths; the carbon fiber composite cloth is made of carbon fiber and metal fiber. A metal pad is fixedly mounted on the substrate, and the main body is welded to the metal pad.

[0009] Optionally, the plane containing each carbon fiber cloth or the plane containing each carbon fiber composite cloth is parallel to the substrate, and the reinforcing sheet also includes welded components; The welded parts are fixedly connected to the reinforcement body, and the reinforcement body is welded to the metal pad through the welded parts.

[0010] Optionally, multiple welded components are arranged at intervals along the length of the reinforced body; the reinforced body has multiple reinforced through holes, and the welded components include: a pressing part and a connecting part; The pressing part and the metal pad are located on opposite sides of the reinforcement body. One end of the connecting part is fixedly connected to the pressing part, and the other end of the connecting part passes through the corresponding reinforcement through hole and is welded to the metal pad. The pressing part abuts against the reinforcement body.

[0011] Optionally, the welded component may further include: a welded portion; The welding part is fixedly connected to the other end of the connecting part, the welding part abuts against the reinforcing body, and the connecting part is welded to the metal pad through the welding part.

[0012] Optionally, an adhesive is also formed between the reinforcing body and the substrate; The reinforcing body is bonded to the substrate with an adhesive.

[0013] Optionally, the reinforcing body includes a stacked structure in which multiple carbon fiber cloths and multiple metal fiber layers are stacked alternately.

[0014] Optionally, the surface of the reinforcing body facing the substrate is plated with a metal layer, and the reinforcing body is welded to the substrate through the metal layer.

[0015] In a second aspect, the present invention provides a method for fabricating a chip packaging structure as described in any one of the first aspects, the method comprising: Provide reinforcement plates; The reinforcing sheet is soldered to the metal pad on the substrate.

[0016] Optionally, the steps of providing the reinforcing sheet include: Multiple carbon fiber fabrics are stacked and reinforced to obtain the processed sheet material; Reinforcement through holes are drilled in the processed sheet material; The sheet metal is cut and processed to obtain the reinforced main body; The welded parts are fixed to the reinforced body by reinforcing the through holes.

[0017] Optionally, the step of soldering the reinforcing sheet to the metal pad on the substrate includes: The substrate and the reinforcing sheet are placed in the pressing cavity of the magnetic carrier to press the reinforcing sheet together with the substrate through a metal pad; The substrate and the reinforcing sheet are reflow soldered to bond the reinforcing sheet to the substrate via metal pads.

[0018] The chip packaging structure and its fabrication method provided in this invention form a reinforcing sheet by stacking and reinforcing multiple carbon fiber cloths or multiple carbon fiber composite cloths. This utilizes the advantages of carbon fiber, such as high modulus, lightweight, high stiffness, high strength, and low elastic modulus. While reducing the thickness of the reinforcing sheet, it also increases the structural strength of the reinforcing sheet. Welding the reinforcing sheet to the substrate ensures the reinforcement effect of the reinforcing sheet on the substrate and effectively avoids substrate warping. It is particularly suitable for substrates with a length or width exceeding 100mm. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic partial cross-sectional view of a chip packaging structure according to an embodiment of this application; Figure 2 This is a schematic top view of a chip packaging structure according to an embodiment of this application; Figure 3 for Figure 2 A schematic cross-sectional view along the AA direction; Figure 4 for Figure 2 A schematic cross-sectional view along the BB direction; Figure 5 This is a schematic cross-sectional view of a weldment similar to an n-type according to an embodiment of this application; Figure 6 This is a schematic cross-sectional view of a weldment similar to an m-shape according to an embodiment of this application; Figure 7 This is a schematic cross-sectional view of a substrate and a reinforcing sheet being pressed together in a magnetic carrier according to an embodiment of this application.

[0021] Figure label: 1. Substrate; 11. Metal pad; 2. Reinforcing sheet; 21. Reinforcing body; 211. Reinforcing through hole; 212. Countersunk groove; 22. Welding component; 221. Pressing part; 222. Connecting part; 223. Welding part; 31. Core; 32. Solder paste layer; 33. Solder ball; 41. Metal cover plate; 42. Base; 43. Pressing cavity. Detailed Implementation

[0022] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0024] Spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, an element or feature described as “below,” “below,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0025] It should be noted that when an element is referred to as "fixedly connected" to another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is referred to as being "directly on" another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0026] It should also be understood that the terms “including / comprise” or “have” specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0027] In a first aspect, one embodiment of the present invention provides a chip packaging structure, combined with Figure 1 and Figure 2 The chip packaging structure includes: substrate 1 and reinforcement sheet 2.

[0028] The reinforcing sheet 2 includes a reinforcing body 21 formed by stacking and reinforcing multiple carbon fiber cloths or multiple carbon fiber composite cloths. The carbon fiber cloth is made from pure carbon fiber; the carbon fiber composite cloth is made from, but is not limited to, carbon fiber and metal fiber, such as 60%-80% carbon fiber and 20%-40% metal fiber. The metal fibers involved in this invention include, but are not limited to, one or more of steel fiber, aluminum fiber, copper fiber, and nickel fiber. This allows the reinforcing sheet 2 to possess not only certain characteristics of carbon fiber cloth but also certain electrical conductivity, thermal conductivity, and ductility characteristics of metal fibers.

[0029] The specific processing methods for carbon fiber cloth and carbon fiber composite cloth can be achieved by weaving (such as plain weave, twill weave, satin weave), knitting, three-dimensional weaving and other processes to form a fiber network structure of "alternating warp and weft" or "interlayer hybrid". This embodiment does not limit this.

[0030] Regardless of whether carbon fiber cloth or carbon fiber composite cloth is used to form the reinforcing body 21, the reinforcement molding method includes, but is not limited to, autoclave molding or compression molding processes. The thickness of the reinforcing body 21 is controlled by laminating multiple carbon fiber cloths or multiple carbon fiber composite cloths with resin. The specific thickness of the reinforcing body 21 can be customized according to the specific packaging size. At the same time, the coefficient of thermal expansion (CTE) of the reinforcing body 21 can be precisely controlled by controlling the orientation of each fiber, the selection of resin, and the layup design. This embodiment will not elaborate on these aspects.

[0031] Combination Figure 1 , Figure 3 and Figure 4 A metal pad 11 is fixedly disposed on the substrate 1. The reinforcing body 21 is welded to the metal pad 11. The size, number and position of the metal pad 11 are determined according to the size of the substrate 1 and the distribution of functional devices on it; the functional devices include, but are not limited to, chiplets 31 and passive devices such as capacitors.

[0032] In this embodiment, the reinforcing body 21 is formed by stacking multiple single-layer carbon fiber cloths in the vertical direction and reinforcing them with resin material. The reinforcing body 21 is disposed on the upper surface of the substrate 1. The plane containing each carbon fiber cloth or each carbon fiber composite cloth is parallel to the substrate 1. It should be noted that the parallelism between the plane containing the carbon fiber cloth or each carbon fiber composite cloth and the substrate 1 is a state obtained under ideal process conditions. In the actual processing and preparation, some or all of the planes containing the carbon fiber cloth or carbon fiber composite cloth are allowed to have a certain degree of parallelism with the substrate 1. This embodiment does not limit the specific range of deviation.

[0033] It is understandable that carbon fiber has a density of 1.55~1.8 g / cm³, which is 1 / 5.8 times that of pure copper (8.96 g / cm³), 1 / 4.5 times that of steel (7.8 g / cm³), and 1 / 2.5 times that of titanium (4.5 g / cm³). Therefore, it can be seen that the reinforced body 21 formed by carbon fiber material has the characteristics of lightweight.

[0034] Meanwhile, the axial stiffness of carbon fiber is 90.5 GPa to 228 GPa, which is 1.1 to 1.2 times that of steel (190 GPa to 200 GPa), 1.7 to 2.0 times that of titanium (110 GPa to 130 GPa), and 3 to 4 times that of aluminum (69 GPa to 79 GPa). It can be seen that the reinforced body 21 formed by carbon fiber material has the characteristic of low elastic modulus.

[0035] In addition, the tensile strength of carbon fiber is 3000MPa~7000MPa, which far exceeds the tensile strength of titanium alloys, such as TC4 titanium alloy with a tensile strength of 1820 MPa, steel (500MPa~2000 MPa) and copper (200MPa~300 MPa). It can be seen that the reinforcing body 21 formed by carbon fiber material has high tensile strength.

[0036] In addition, the linear thermal expansion coefficient of carbon fiber is 2×10⁻⁶. -6 / °C, which is much lower than that of titanium (8×10 -6 / °C), steel (11×10) -6 / °C), copper (17×10) -6 The coefficient of thermal expansion (°C) indicates that the reinforced body 21 made of carbon fiber material has a low coefficient of thermal expansion.

[0037] The chip packaging structure provided in this embodiment forms a reinforcing sheet 2 by stacking and reinforcing multiple carbon fiber cloths into a reinforcing body 21. It utilizes the advantages of carbon fiber, such as high modulus, lightweight, high stiffness, high strength and low elastic modulus. While reducing the thickness of the reinforcing sheet 2, it also increases the structural strength of the reinforcing sheet 2. Welding the reinforcing sheet 2 to the substrate 1 ensures the reinforcing effect of the reinforcing sheet 2 on the substrate 1 and effectively avoids warping of the substrate 1. It is particularly suitable for substrates 1 with a length or width exceeding 100mm.

[0038] The shape of the reinforcing plate 2 can be a square, cross, H-shaped, straight, or L-shaped, etc., and can be selected according to the layout of the functional devices on the substrate 1. In this embodiment, the reinforcing plate 2 is square, and all the functional devices on the substrate 1 are located inside the reinforcing plate 2.

[0039] In a further optional embodiment of this embodiment, combined with Figure 1 , Figure 3 and Figure 4 The reinforcing plate 2 also includes a welded component 22.

[0040] The welding component 22 is fixedly connected to the reinforcing body 21, and the reinforcing body 21 is welded to the metal pad 11 through the welding component 22.

[0041] The welded component 22 can be a screw structure located at the bottom of the reinforcing body 21, a bolt structure penetrating the reinforcing body 21 in the vertical direction, or a bracket similar to an n-type or m-type covering the outside of the reinforcing body 21, combined with... Figure 5 and Figure 6 .

[0042] In this embodiment, combined with Figure 1 , Figure 2 , Figure 3 and Figure 4 The reinforcement body 21 has multiple welded parts 22, which are arranged at intervals along its length. The reinforcement body 21 has multiple reinforcement through holes 211, each corresponding to one of the welded parts 22. Each welded part 22 includes a pressing portion 221 and a connecting portion 222. The connecting portion 222 is a rod-shaped structure adapted to the reinforcement through hole 211, and the pressing portion 221 is a sheet-like structure coaxial with the connecting portion 222, with the diameter of the pressing portion 221 being larger than the diameter of the reinforcement through hole 211.

[0043] The pressing part 221 and the metal pad 11 are located on opposite sides of the reinforcing body 21. The top end of the connecting part 222 is fixedly connected to the pressing part 221. The bottom end of the connecting part 222 passes through the reinforcing body 211 through the corresponding reinforcing through hole 211 and is welded to the metal pad 11. The pressing part 221 abuts against the top of the reinforcing body 21.

[0044] By providing a pressing part 221 at the top of the connecting part 222, after the reinforcing sheet 2 is welded to the substrate 1, the pressing part 221 and the substrate 1 together clamp the reinforcing body 21, thereby limiting the multiple single-layer carbon fiber cloths in the vertical direction and ensuring the stability of the reinforcing body 21 structure.

[0045] Furthermore, in combination Figure 1 , Figure 3 and Figure 4 The welding component 22 further includes a welding portion 223. The welding portion 223 is fixedly connected to the bottom end of the connecting portion 222, and the welding portion 223 abuts against the bottom of the reinforcing body 21. The connecting portion 222 is welded to the metal pad 11 through the welding portion 223. The materials of the pressing portion 221, the connecting portion 222, and the welding portion 223 are all metal materials. In this embodiment, the entire material of the welding component 22 is copper, but it is not limited to this. At the same time, a solder paste layer 32 is formed between the welding portion 223 and the metal pad 11. The melting point of the solder paste in the solder paste layer 32 is higher than the welding temperature used to weld the core 31 to the substrate 1. Thus, when the core 31 is welded to the substrate 1, the solder paste layer 32 will not melt, thereby enabling the reinforcing sheet 2 to resist the warping of the substrate 1 when the core 31 is welded.

[0046] The welding part 223 is a sheet-like structure coaxial with the connecting part 222, and the diameter of the welding part 223 is larger than the diameter of the reinforcing through hole 211. The welding part 223 is welded to the corresponding metal pad 11 by solder paste applied on the metal pad 11. The solder paste contains SnSb alloy, such as SnSb10Ni0.5, and the melting point of the solder paste containing SnSb10Ni0.5 is 265℃~275℃.

[0047] By providing a welding part 223 at the bottom of the connecting part 222, it is possible not only to cooperate with the pressing part 221 to clamp multiple single-layer carbon fiber cloths, thereby improving the structural stability of the reinforced body 21, but also to increase the contact area between the welded part 22 and the metal pad 11, thereby further improving the welding stability between the reinforcing sheet 2 and the substrate 1.

[0048] In this embodiment, countersunk grooves 212 are formed on both the upper and lower surfaces of the reinforcing body 21. The countersunk grooves 212 at both ends communicate with the corresponding reinforcing through holes 211 to form countersunk through holes. The countersunk grooves 212 at both ends are adapted to the corresponding pressing parts 221 and welding parts 223. The upper surface of the pressing part 221 is flush with the upper surface of the reinforcing body 21, and the lower surface of the welding part 223 is flush with the lower surface of the reinforcing body 21.

[0049] By creating a countersunk groove 212 on the reinforcing body 21, the thickness of the reinforcing sheet 2 can be effectively reduced, thereby improving the space utilization of the chip packaging structure.

[0050] In a further optional embodiment of this invention, a protective film is formed on the surface of the welded part 22, or on the upper surface of the pressing part 221 and the lower surface of the welded part 223, to prevent the welded part 22 from being oxidized and affecting the welding effect. The protective film can be formed on the corresponding surface by bonding or electroplating. The material of the protective film includes, but is not limited to, gold or tin.

[0051] In a further optional embodiment of this invention, an adhesive is also formed between the reinforcing body 21 and the substrate 1. The reinforcing body 21 is bonded to the substrate 1 by the adhesive.

[0052] In this embodiment, the substrate 1 and the reinforcing sheet 2 are fixedly connected by a combination of welding and adhesive. The welding points formed by the substrate 1 and the reinforcing sheet 2 provide multiple rigid connection points for the reinforcing sheet 2. The polymer adhesive can alleviate the stress on the rigid connection points in various directions to a certain extent, preventing excessive stress from causing the rigid connection points to break and fail. The position and number of rigid connection points can be specifically designed according to the warpage of the substrate 1, which can be done through simulation or design of experiments (DOE).

[0053] In a further optional embodiment of this example, a core 31 is also fixedly disposed on the substrate 1. The core 31 and the reinforcing sheet 2 are located on the same side of the substrate 1. Solder balls 33 are fixedly disposed on the surface of the substrate 1 away from the core 31.

[0054] The chip packaging structure provided in this embodiment utilizes the high axial stiffness and low coefficient of thermal expansion of carbon fiber material. By setting multiple welding points on the substrate 1, the deformation trend of the substrate 1 can be limited during high-temperature reflow, thereby effectively controlling the warpage of the substrate 1. At the same time, the carbon fiber material can achieve warpage control of the substrate 1 with a lower thickness, thereby improving the problem of the existing thick reinforcement sheet 2 affecting the SAT detection accuracy.

[0055] Secondly, one embodiment of the present invention provides another chip packaging structure, which differs from the chip packaging structure in the first aspect in that, in this embodiment, the reinforcing body 21 includes not only multiple carbon fiber cloths but also multiple metal fiber layers. The multiple carbon fiber cloths and multiple metal fiber layers are alternately stacked to form a stacked structure.

[0056] Thirdly, an embodiment of the present invention provides a third chip packaging structure, which differs from the chip packaging structure in the first aspect in that, in this embodiment, the surface of the reinforcing body 21 facing the substrate 1 is plated with a metal layer, and the reinforcing body 21 is welded to the substrate 1 through the metal layer.

[0057] It should be noted that, in this embodiment, the reinforcing plate 2 may be provided with a welded component 22 including a pressing part 221, a connecting part 222, and a welding part 223 to reinforce the reinforcing body 21, or the welded component 22 may not be provided. In this embodiment, the reinforcing plate 2 is provided with a welded component 22 including a pressing part 221, a connecting part 222, and a welding part 223 as an example.

[0058] Fourthly, the present invention provides a method for preparing a chip packaging structure, the method comprising steps S101 to S102.

[0059] Step S101: Provide reinforcement sheet 2.

[0060] Step S102: Weld the reinforcing sheet 2 to the metal pad 11 on the substrate 1 to form a bond. Figure 1 and Figure 2 .

[0061] Understandably, this preparation method can be used to prepare any of the chip packaging structures described in the first to third aspects.

[0062] The step of welding the reinforcing sheet 2 to the metal pad 11 on the substrate 1 further includes steps S1021 to S1022.

[0063] Step S1021: Place the substrate 1 and the reinforcing sheet 2 into the pressing cavity 43 of the magnetic carrier to press the reinforcing sheet 2 together with the substrate 1 via the metal pad 11, thus bonding them together. Figure 1 and Figure 7 .

[0064] Specifically, in combination Figure 7 The metal cover plate 41 and the base 42 in the magnetic carrier are magnetically connected to form a pressing cavity 43. After the substrate 1 and the reinforcing sheet 2 are placed in the pressing cavity 43 of the magnetic carrier in a stacked manner, the metal cover plate 41 presses the substrate 1 and the reinforcing sheet 2 into the pressing cavity 43 by the magnetic force generated by the magnetic block on the base 42.

[0065] In this process, welding the substrate 1 and the reinforcing sheet 2 inside the magnetic carrier can ensure that the substrate 1 after welding the reinforcing sheet 2 is as flat as possible, and avoid the substrate 1 naturally stretching out after the solder reflow, while the solder paste hardens and causes the substrate 1 after welding the reinforcing sheet 2 to form a large warp.

[0066] Step S1022: Reflow soldering is performed on the substrate 1 and the reinforcing sheet 2 so that the reinforcing sheet 2 is soldered to the substrate 1 through the metal pad 11.

[0067] It should be noted that the rigid connection formed by soldering the metal pad 11 to the substrate 1 can withstand reflow soldering at temperatures below 250°C. After the substrate 1 and the reinforcing sheet 2 are soldered together, the reflow temperature used in subsequent packaging processes is below 250°C.

[0068] The subsequent packaging processes include, but are not limited to, loading the core 31 on the upper surface of the substrate 1 and forming the solder ball 33 on the lower surface of the substrate 1. These will not be described in detail in this embodiment.

[0069] In a further optional embodiment of this embodiment, the step of providing the reinforcing sheet 2 during the preparation of the chip packaging structure as described in the first aspect further includes steps S1011 to S1014.

[0070] Step S1011: Stack multiple carbon fiber cloths and reinforce them with resin to obtain the processed board.

[0071] Step S1012: A reinforcing through hole 211 and a countersunk groove 212 are made on the processed plate, combined with... Figure 1 .

[0072] Step S1013: Cut and process the plate to obtain the reinforced body 21.

[0073] In a further optional embodiment of this example, the step of cutting and processing the sheet metal to obtain the reinforced body 21 includes: using a polycrystalline diamond (PCD) tool to cut and process the sheet metal in conjunction with ultrasonic-assisted technology to obtain the reinforced body 21. The cutting speed of the PCD tool is controlled at 200 m / min to 400 m / min, which effectively reduces delamination and burrs in the reinforced body 21; the frequency of the ultrasonic waves is 20 kHz to 40 kHz, which reduces the cutting force of the PCD tool, avoids delamination of the hole walls in the reinforced body 21, and thus improves the assembly accuracy of the welded part 22.

[0074] Step S1014: Fix the welded part 22 to the reinforcing body 21 through the reinforcing through hole 211 and countersunk groove 212, and combine Figure 1 .

[0075] It is understandable that the specific steps for providing the reinforcing sheet 2 in the process of preparing the chip packaging structure as in the second aspect are different from the specific steps for providing the reinforcing sheet 2 in the process of preparing the chip packaging structure as in the first aspect. In the process of preparing the chip packaging structure as in the second aspect, step S1011 in steps S1011 to S1014 above is simply replaced by: stacking multiple carbon fiber cloths and multiple metal fiber cloths alternately and reinforcing them with resin to obtain the processed board.

[0076] The specific steps for providing the reinforcing sheet 2 in the process of preparing the chip packaging structure as described in the third aspect can be adapted based on the specific steps for providing the reinforcing sheet 2 in the process of preparing the chip packaging structure as described in the previous aspect, and will not be described in detail here.

[0077] In a further optional embodiment of this embodiment, before performing step S102, the preparation method further includes: printing a solder paste layer 32 on the substrate 1 and applying an adhesive.

[0078] In the description of this specification, the references to terms such as "some embodiments," "other embodiments," "ideal embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0079] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A chip packaging structure, characterized in that, The chip packaging structure includes: a substrate and a reinforcing sheet; The reinforcing sheet includes: a reinforcing body formed by stacking and reinforcing multiple carbon fiber cloths or multiple carbon fiber composite cloths; the carbon fiber composite cloth is made of carbon fiber and metal fiber. A metal pad is fixedly disposed on the substrate, and the reinforcing body is welded to the metal pad.

2. The chip packaging structure according to claim 1, characterized in that, Each plane containing a carbon fiber cloth or each plane containing a carbon fiber composite cloth is parallel to the substrate, and the reinforcing sheet also includes welded components; The welded component is fixedly connected to the reinforcing body, and the reinforcing body is welded to the metal pad through the welded component.

3. The chip packaging structure according to claim 2, characterized in that, Multiple welded components are arranged at intervals along the length of the reinforcing body; the reinforcing body has multiple reinforcing through holes, and the welded components include: a pressing part and a connecting part; The pressing part and the metal pad are located on opposite sides of the reinforcing body. One end of the connecting part is fixedly connected to the pressing part, and the other end of the connecting part passes through the reinforcing body through a corresponding reinforcing through hole and is welded to the metal pad. The pressing part abuts against the reinforcing body.

4. The chip packaging structure according to claim 3, characterized in that, The welded component further includes: a welded section; The welding part is fixedly connected to the other end of the connecting part, the welding part abuts against the reinforcing body, and the connecting part is welded to the metal pad through the welding part.

5. The chip packaging structure according to claim 1, characterized in that, An adhesive is also formed between the reinforcing body and the substrate; The reinforcing body is bonded to the substrate by the adhesive.

6. The chip packaging structure according to claim 1, characterized in that, The reinforcement body comprises a stacked structure in which multiple carbon fiber cloths and multiple metal fiber layers are stacked alternately.

7. The chip packaging structure according to claim 1, characterized in that, The surface of the reinforcing body facing the substrate is plated with a metal layer, and the reinforcing body is welded to the substrate through the metal layer.

8. A method for fabricating a chip packaging structure as described in any one of claims 1 to 7, characterized in that, The preparation method includes: Provide reinforcement plates; The reinforcing sheet is welded to the metal pad on the substrate.

9. The preparation method according to claim 8, characterized in that, In the process of preparing the chip package structure as described in any one of claims 1 to 6, the step of providing the reinforcement sheet includes: Multiple carbon fiber fabrics are stacked and reinforced to obtain the processed sheet material; Reinforcement through holes are made in the processed plate material; The processed sheet material is cut to obtain the reinforced body; The welded component is fixed to the reinforced body through the reinforced through hole.

10. The preparation method according to claim 8, characterized in that, The step of welding the reinforcing sheet to the metal pad on the substrate includes: The substrate and the reinforcing sheet are placed in the pressing cavity of the magnetic carrier to press the reinforcing sheet together with the substrate through the metal pad; The substrate and the reinforcing sheet are reflow soldered so that the reinforcing sheet is soldered to the substrate through the metal pad.

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