A method for molding a chip

Abstract

A chip plastic packaging method relates to the technical field of semiconductors, and the method comprises the following steps: providing at least one unit to be plastic packaged, the unit to be plastic packaged has completed a patch process and a wire bonding process, and the unit to be plastic packaged has a preset product total thickness; providing a standard plastic packaging mold, the standard plastic packaging mold is internally provided with a cavity, and the cavity has a fixed cavity total depth; obtaining a backing plate, the thickness of the backing plate is equal to the cavity total depth minus the product total thickness; placing the backing plate and the unit to be plastic packaged in the cavity of the standard plastic packaging mold, and the backing plate is located below the unit to be plastic packaged; plastic packaging the unit to be plastic packaged to form a plastic packaging body; taking out the plastic packaging body from the standard plastic packaging mold, and removing the backing plate to obtain a packaged product. The chip plastic packaging method effectively solves the problems of small-batch sample total thickness mismatch, long cycle and high cost by placing the backing plate with a thickness equal to the cavity total depth minus the product total thickness below the unit to be plastic packaged and then placing the unit to be plastic packaged in the standard plastic packaging mold for plastic packaging.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a method for encapsulating a chip. Background Technology

[0002] In the semiconductor packaging field, molding is a critical process for protecting chips from environmental stress. Currently, when molding chips or substrate units that have undergone surface mount and wire bonding processes, custom molds that match the product design dimensions are typically used. The total thickness of the molded product is determined by both the substrate thickness and the molding compound thickness, which are constrained by the lower mold platen and the upper mold cavity, respectively. When the designed total product thickness does not match the corresponding dimensions of existing standard molds, the industry practice is to either customize the entire mold, replace the upper mold cavity / lower mold platen separately, or adjust the mold closing height. While these solutions can resolve the mismatch between the designed total product thickness and the corresponding dimensions of existing standard molds, the manufacturing cost of the molds or fixtures is high, the manufacturing cycle is long, and each change in the total product thickness requires reinvestment in hardware modifications, making it difficult to meet the packaging needs of small-batch, multi-variety, and rapidly iterating samples during the product development phase.

[0003] However, during product development, sample verification, or small-batch trial production, technicians often need to use existing standard molding dies to quickly and cost-effectively mold samples of different product thicknesses. Customizing dies or replacing components using traditional methods would significantly increase project costs and extend the development cycle; moreover, the cavity depth of existing standard dies is a fixed value and cannot directly accommodate units with mismatched product thicknesses. Therefore, how to flexibly match samples of different product thicknesses using the same set of standard molding dies without changing any parts of the dies or customizing additional tooling, and achieve rapid, cost-effective, and reliable molding, has become a long-standing and urgent technical challenge in the industry. Summary of the Invention

[0004] The purpose of this invention is to provide a chip encapsulation method. By obtaining a pad with a thickness equal to the total cavity depth minus the total product thickness, the pad is placed below the unit to be encapsulated and placed together into the cavity of a standard encapsulation mold for encapsulation. This method enables the rapid and low-cost encapsulation of samples with different total product thicknesses using the same set of standard encapsulation molds without changing or adjusting any parts of the mold. It effectively solves the problems of mismatched total thicknesses, long cycles, and high costs associated with small-batch samples in the R&D stage.

[0005] The embodiments of the present invention are implemented as follows: A first aspect of this invention provides a method for encapsulating a chip, the method comprising: Provide at least one unit to be molded, the unit to be molded has completed the surface mount technology and wire bonding process, and the unit to be molded has a preset total product thickness; A standard molding die is provided, wherein the standard molding die has an internal cavity with a fixed total cavity depth; Obtain a backing plate, the thickness of which is equal to the total depth of the cavity minus the total thickness of the product; The pad and the unit to be molded are placed in the cavity of the standard molding mold, with the pad located below the unit to be molded; The unit to be encapsulated is encapsulated to form an encapsulated body; The encapsulated body is removed from the standard encapsulation mold, and the pad is removed to obtain the encapsulated finished product.

[0006] As one possible implementation, when the thickness of the substrate of the unit to be molded does not match the depth of the lower mold cavity of the standard molding die, providing at least one unit to be molded includes: A raw substrate is provided, the raw substrate including an effective area with chips mounted and an edge area without chips mounted; The edge region is cut and separated from the original substrate to obtain a substrate unit containing the effective region as the unit to be encapsulated. A carrier plate is provided, the thickness of which is equal to the depth of the lower mold cavity, and the overall planar dimensions of the carrier plate and the unit to be molded are matched with the planar dimensions of the cavity of the standard molding mold. The unit to be encapsulated is fixed to the carrier plate, so that the upper surface of the unit to be encapsulated is flush with the upper surface of the carrier plate; The step of placing the pad and the unit to be encapsulated into the cavity of the standard encapsulation mold includes: The pad and the carrier plate on which the unit to be sealed is fixed are placed in the cavity of the standard sealing mold, with the pad located below the unit to be sealed.

[0007] In one possible implementation, the carrier plate has a hollow area, and the unit to be encapsulated is fixed within the hollow area.

[0008] In one possible implementation, the carrier plate includes multiple sub-carrier plates, which are arranged around the periphery of the unit to be encapsulated.

[0009] In one possible implementation, the unit to be encapsulated is spliced ​​with multiple subcarrier plates using high-temperature resistant tape.

[0010] As one possible implementation, the high-temperature resistant tape is attached along the splicing edge between the unit to be encapsulated and the subcarrier plate to form a cofferdam structure around the unit to be encapsulated.

[0011] As one possible implementation, the projected area of ​​the pad on the standard molding die is larger than the projected area of ​​the unit to be molded on the standard molding die.

[0012] As one possible implementation, the pad is made of a high-temperature resistant material.

[0013] As one possible implementation, after removing the molded body from the standard molding die, the method further includes: The encapsulated body undergoes post-curing treatment.

[0014] As one possible implementation, the standard molding die is an injection molding die or a compression molding die.

[0015] The beneficial effects of the embodiments of the present invention include: The encapsulation method for this chip involves obtaining a pad with a thickness equal to the total depth of the standard encapsulation mold cavity minus the total thickness of the unit product to be encapsulated. This pad is then placed below the unit to be encapsulated and placed together into the mold cavity for encapsulation. This method enables the rapid and low-cost encapsulation of samples with different thickness requirements using the same set of standard molds without changing or adjusting any parts of the mold. It effectively solves the problems of difficult thickness adaptation, long cycle, and high cost for small batch samples in the R&D stage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the fabrication process of a chip encapsulation method in the prior art; Figure 2 This is a schematic diagram illustrating the fabrication process of the chip encapsulation method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the preparation process of the chip encapsulation method provided in the first embodiment of the present invention; Figure 4 for Figure 3 The obtained cross-sectional view of the unit to be encapsulated and the pad; Figure 5 This is one of the schematic diagrams illustrating the preparation process of the chip encapsulation method provided in the second embodiment of the present invention; Figure 6 This is a second schematic diagram illustrating the preparation process of the chip encapsulation method provided in the second embodiment of the present invention; Figure 7 This is the third schematic diagram illustrating the preparation process of the chip encapsulation method provided in the second embodiment of the present invention; Figure 8 for Figure 7 The obtained cross-sectional view of the unit to be encapsulated and the pad.

[0018] Icons: 10 - Standard molding die; 11 - Upper die; 111 - Upper mold cavity; 12 - Lower die; 121 - Lower die pad; 122 - Lower mold cavity; 20 - Original substrate; A1 - Effective area; A2 - Edge area; 21 - Substrate; 22 - Chip; 30 - Carrier board; B1 - Block sub-carrier board; B2 - U-shaped sub-carrier board; C - Pad; 40 - High temperature resistant tape; 50 - Unit to be molded; d1 - Total product thickness; d2 - Depth of lower mold cavity; d3 - Depth of upper mold cavity; d4 - Total cavity depth; d5 - Pad thickness. Detailed Implementation

[0019] The embodiments described below represent the information necessary for those skilled in the art to practice the embodiments and illustrate the best mode for practicing the embodiments. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and will recognize the application of these concepts not specifically set forth herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0020] It should be understood that when an element (such as a layer, region, or substrate) is referred to as "on another element" or "extending to another element," it may be directly on another element or directly extending to another element, or there may be an intermediate element. Similarly, it should be understood that when an element (such as a layer, region, or substrate) is referred to as "on another element" or "extending over another element," it may be directly on another element or directly extending to another element, or there may be an intermediate element.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that, when used herein, the term “comprising” indicates the presence of the stated feature, integer, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups of the foregoing.

[0022] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that the terms used herein should be interpreted as having the same meaning as they would in the context of this specification and the relevant field, and not in an idealized or overly formal sense, unless expressly defined herein.

[0023] In the field of semiconductor packaging, such as Figure 1 As shown, existing molding methods typically employ methods such as customizing the entire mold (including the upper mold 11 and lower mold 12), replacing the upper mold cavity 111 or the lower mold pad 121, or adjusting the mold closing height when the total product thickness d1 does not match the total mold cavity depth d4. For example, when the total product thickness d1 (i.e., the sum of the substrate 21 thickness and the molding compound thickness) is greater than the total mold cavity depth d4 (i.e., the sum of the upper mold cavity depth d3 and the lower mold cavity depth d2), it is necessary to deepen the upper mold cavity 111 or thin the lower mold pad 121; when the total product thickness d1 is less than the total mold cavity depth d4, it is necessary to thin the upper mold cavity 111 or thicken the lower mold pad 121. These hardware modification solutions are not only costly (the cost of a single modification is usually tens of thousands to hundreds of thousands of yuan), but also time-consuming (generally requiring 1 to 3 months). Each change in the total product thickness d1 requires reinvestment in hardware modification, which cannot meet the packaging needs of small-batch, multi-variety, and rapidly iterating samples in the R&D stage.

[0024] To solve the above problems, such as Figures 2 to 8 As shown, this application provides a molding encapsulation method for a chip 22. By obtaining a pad C with a thickness equal to the total cavity depth d4 minus the total product thickness d1, and placing the pad C below the unit to be molded 50, the chip is placed together with the pad C into the cavity of a standard molding mold 10 for molding. This method enables the rapid and low-cost encapsulation of samples with different total product thicknesses d1 using the same set of standard molding molds 10 without changing or adjusting any parts of the mold. This effectively solves the problems of mismatched total thicknesses, long cycles, and high costs associated with small-batch samples in the R&D stage.

[0025] Specifically, in a first aspect of this application, a method for encapsulating a chip 22 is provided, the method comprising: S100, Provide at least one unit 50 to be molded, the unit 50 to be molded has completed the surface mount process and wire bonding process, and the unit 50 to be molded has a preset total product thickness d1; It should be noted that, as Figure 3As shown, this step clarifies that the unit to be molded 50 is a chip 22 or substrate 21 unit that has completed the surface mount and wire bonding processes, and defines its "total product thickness d1" (i.e., the target thickness value of the final packaged product). Unlike conventional mass production where the total thickness is directly determined by a custom mold, this application uses the total product thickness d1 as an independent input parameter, providing a calculation benchmark for subsequent thickness compensation via the pad C. The unit to be molded 50 can be a single independent chip 22 that has completed the surface mount and wire bonding processes, or a substrate 21 unit containing at least one chip 22 cut from the original substrate 20. The source and size of the unit to be molded 50 are not limited, so that this method can be adapted to multiple varieties and small batches of samples in the R&D stage. This step clarifies the state and thickness parameters of the unit to be molded 50 from the source, laying the foundation for the subsequent "thickness compensation" technical path.

[0026] S200, Provides a standard molding die 10, the standard molding die 10 has a cavity inside, the cavity has a fixed total cavity depth d4; It should be noted that, as Figure 2 As shown, this step explicitly uses an existing standard molding die 10, whose total cavity depth d4 is a fixed value and cannot be adjusted. The total cavity depth d4 of standard molding dies 10 in the industry (such as injection molding dies or compression molding dies) is usually designed for a specific type of standard product, such as common specifications like 0.5mm, 0.6mm, 0.8mm, and 1.0mm. When the total thickness d1 of the R&D sample does not match the total cavity depth d4 of these standard molding dies 10, traditional solutions require customizing the die or replacing parts. This application, however, compensates by providing a thickness-matching shim C, without requiring any modification to the standard molding die 10 itself. This step embodies the core design concept of this application: "reusing standard molding equipment without modifying the molding die," directly utilizing standard die resources that are widely available in the industry, technologically mature, and for which fixed asset investment has already been completed, avoiding additional die customization costs and time.

[0027] S300, Obtain the pad C. The thickness d5 of the pad is equal to the total cavity depth d4 minus the total product thickness d1. It should be noted that, as Figure 3As shown, this step uses a simple subtraction formula: The thickness d5 of the pad = Total cavity depth d4 - Total product thickness d1, to calculate the required pad thickness d5. For example, if the total cavity depth d4 of the standard molding die 10 is 0.8mm, and the required total product thickness d1 of the unit to be molded 50 is 0.5mm, then the pad thickness d5 should be 0.3mm; if the total cavity depth d4 of the standard molding die 10 is 0.6mm, and the required total product thickness d1 of the unit to be molded 50 is 0.45mm, then the pad thickness d5 should be 0.15mm. The pad C can be made of high-temperature resistant, high-hardness, and smooth-surfaced materials (such as stainless steel, hard alloy, ceramic, or high-temperature resistant engineering plastics), and its thickness accuracy can be controlled within the micrometer level (usually within ±5μm). Due to the simple structure of the pad C (only a flat plate with a certain thickness), the processing cost is extremely low (usually only a few hundred to several thousand yuan), and the processing cycle is extremely short (it can be completed within 1-2 days). Compared with traditional custom molds (costing tens of thousands to hundreds of thousands of yuan and taking 1-3 months), this significantly reduces R&D costs and shortens the R&D cycle.

[0028] S400: Place the pad C and the unit 50 to be molded into the cavity of the standard molding mold 10, with the pad C located below the unit 50 to be molded. It should be noted that, as Figure 2 As shown, in this step, the pad C and the unit to be molded 50 are placed into the cavity with the pad C at the bottom and the unit to be molded 50 at the top. The order of placement is not limited; the pad C can be placed at the bottom of the cavity first, and then the unit to be molded 50 can be placed on top of the pad C; alternatively, the pad C and the unit to be molded 50 can be pre-stacked and then placed together. Regardless of the method, as long as the pad C is ultimately located below the unit to be molded 50, thickness compensation is achieved. The function of the pad C is to raise the vertical position of the unit to be molded 50 in the cavity, and the raising amount of the unit to be molded 50 is equal to the thickness d5 of the pad. Since the total product thickness d1 of the unit to be molded 50 is predetermined, and the total cavity depth d4 of the mold is fixed, the pad C fills the difference between the two, ensuring that the top of the unit to be molded 50 and the top surface of the upper mold 11 leave just the required molding space for the product. During molding, molten molding compound fills the molding space, and after solidification, a molded body meeting the required thickness is formed. This step does not involve any mechanical modification to the mold, nor does it require any additional fixing or positioning devices, making the operation simple. The spacer C and the unit to be molded 50 do not need to be fixed; their relative positions are maintained solely by gravity, further simplifying the process and reducing costs.

[0029] S500: The unit to be molded 50 is molded to form a molded body; It should be noted that this step encapsulates the unit 50 to be encapsulated according to standard encapsulation process parameters (such as temperature, pressure, injection speed, or mold closing speed). Due to the presence of the backing plate C, the position of the unit 50 to be encapsulated is precisely raised in the cavity, and the encapsulating material naturally forms an encapsulated body consistent with the total thickness d1 of the product during filling. After encapsulation, the encapsulated body is firmly bonded to the unit 50 to be encapsulated, while the backing plate C is only temporarily placed and does not adhere to or fuse with any component. This step directly uses the standard process parameters of standard encapsulation equipment, eliminating the need to readjust the equipment due to changes in thickness, further shortening the process preparation time. At the same time, the backing plate C can withstand the high temperature and high pressure environment (typically 175-200℃, 10-20MPa) during the encapsulation process without deformation or degradation, ensuring the stability of the encapsulation process and the consistency of the finished product.

[0030] S600. Remove the encapsulated body from the standard encapsulation mold 10 and remove the pad C to obtain the encapsulated finished product.

[0031] It should be noted that after molding, the mold is opened and the molded body is removed (at this time, the pad C usually falls off naturally or is located below the molded body). After removing the pad C, the packaged product is obtained. The pad C itself is not covered by the molding compound, and the removal process is extremely simple, requiring no cutting or chemical corrosion. Moreover, there is no residue on the surface of the pad C, and it can be reused after simple cleaning. Compared with traditional solutions, after customizing the mold or changing the parts, the mold itself cannot be adapted to products of other thicknesses; however, the pad C of this application can be flexibly replaced with pads of different thicknesses according to the total thickness d1 requirements of different products. The same set of standard molds can be adapted to sample packaging of any thickness, realizing the compatibility capability of "one set of molds, multi-thickness compatibility".

[0032] In summary, this application achieves thickness compensation by adding a backing plate C. Without altering any mold components, it utilizes the same standard molding die 10 to encapsulate samples with different total thicknesses d1. The entire process requires no custom molds or replacement of any components, significantly reducing R&D costs and shortening the development cycle. This effectively solves the problems of mismatched total thicknesses, long development cycles, and high costs associated with small-batch samples during the R&D phase.

[0033] As one possible implementation, when the thickness of the substrate 21 of the molding unit 50 does not match the depth d2 of the lower mold cavity of the standard molding mold 10, providing at least one molding unit 50 includes: S101. Provide an original substrate 20, which includes an effective area A1 with the chip 22 mounted and an edge area A2 without the chip 22 mounted. It should be noted that, as Figure 5As shown, in actual R&D scenarios, the molding unit 50 is sometimes not independent, but rather derived from a larger original substrate 20. The original substrate 20 may only have the chip 22 mounted in certain areas (i.e., the effective area A1), while other areas (i.e., the edge area A2) are blank. If the thickness of the original substrate 20 does not match the depth d2 of the lower mold cavity of the standard molding mold 10 (e.g., the thickness of the original substrate 20 is greater than the depth d2 of the lower mold cavity of the standard molding mold 10, or the thickness of the original substrate 20 is less than the depth d2 of the lower mold cavity of the standard molding mold 10), directly placing it into the cavity will affect mold closing or molding material overflow.

[0034] S102, Cut and separate the edge region A2 from the original substrate 20 to obtain a substrate 21 unit containing the effective region A1 as a molding unit 50; It should be noted that, as Figure 5 As shown, by using precision cutting equipment (such as a substrate 21 cutting machine or a depaneling machine), the edge area A2 on the original substrate 20 that does not contain the chip 22 is cut off and separated, leaving only the effective area A1 containing the chip 22. This effective area A1 is used as the unit to be encapsulated 50.

[0035] S103. Provide a carrier plate 30. The thickness of the carrier plate 30 is equal to the depth d2 of the lower mold cavity, and the overall planar dimensions of the carrier plate 30 and the unit to be molded 50 are matched with the planar dimensions of the cavity of the standard molding mold 10. It should be noted that, as Figure 6 As shown, simply using the pad C may not guarantee the stable positioning of the unit 50 to be molded in the cavity. Therefore, this embodiment adds a carrier plate 30, the thickness of which is equal to the depth d2 of the lower mold cavity. The function of the carrier plate 30 is to provide a standardized support platform for the unit 50 to be molded, so that the height reference of the unit 50 to be molded in the cavity matches the depth d2 of the lower mold cavity.

[0036] S104. Fix the unit 50 to be plastic-sealed to the carrier plate 30 so that the upper surface of the unit 50 to be plastic-sealed is flush with the upper surface of the carrier plate 30. It should be noted that, as Figure 6 As shown, the molding unit 50 can be fixed to the carrier plate 30 by means of high-temperature resistant tape 40, mechanical clamps, or vacuum adsorption. After fixing, the molding unit 50 and the carrier plate 30 form a whole, which is convenient for subsequent placement into the mold cavity.

[0037] S105. Place the pad C and the carrier plate 30 on which the molding unit 50 is fixed are placed in the cavity of the standard molding mold 10, with the pad C located below the molding unit 50.

[0038] It should be noted that, as Figure 7 and Figure 8As shown, the pad C is at the bottom, and the carrier plate 30 and the unit to be encapsulated 50 are placed above the pad C. Since the thickness of the carrier plate 30 is equal to the depth d2 of the lower mold cavity, the height of the substrate 21 of the unit to be encapsulated 50 is exactly at the same height position as the lower mold cavity 122 of the standard encapsulation mold 10. The pad C continues to compensate for the difference between the total product thickness d1 and the total cavity depth d4. In this way, even if the thickness of the original substrate 20 does not match the depth d2 of the lower mold cavity of the standard encapsulation mold 10, the same set of standard molds can still be used to complete the encapsulation through the combination of "edge cutting + carrier plate 30 thickness standardization + pad C thickness compensation". This embodiment complements the aforementioned scheme of directly adding the pad C: when the size of the unit to be encapsulated 50 is appropriate and the thickness of the substrate 21 is matched, the pad C can be used directly; when the size of the original substrate 20 is mismatched and / or the thickness of the substrate 21 is mismatched, the combination of "edge cutting + carrier plate 30 thickness standardization + pad C thickness compensation" in this embodiment is adopted. Neither of the two schemes alters any component of the mold, further improving the compatibility of this method.

[0039] As one possible implementation method, such as Figure 6 As shown, the carrier plate 30 has a hollow area, and the unit to be encapsulated 50 is fixed in the hollow area.

[0040] It should be noted that the hollow area design allows the unit to be molded 50 to be embedded inside the carrier plate 30, rather than being attached to its surface. The advantages of this design are: the inner wall of the hollow area provides positioning for the sides of the unit to be molded 50, preventing horizontal displacement during the molding process; simultaneously, the bottom surface of the substrate 21 of the unit to be molded 50 can be flush with or slightly lower than the bottom surface of the carrier plate 30, facilitating contact with the pad C. The size of the hollow area should be slightly larger than the planar dimensions of the unit to be molded 50 (typically 0.1-0.5 mm larger on each side) to facilitate placement and removal. Preferably, the depth of the hollow area should be equal to the thickness of the substrate 21 of the unit to be molded 50, ensuring that after the unit to be molded 50 is embedded, the bottom surface of its substrate 21 is coplanar with the bottom surface of the carrier plate 30, guaranteeing planar contact with the pad C and avoiding localized stress concentration.

[0041] As one possible implementation method, such as Figure 6 As shown, the carrier plate 30 includes multiple sub-carrier plates 30, which are arranged around the periphery of the unit to be encapsulated 50.

[0042] It should be noted that when the shape of the unit to be molded 50 is irregular or its surrounding space is limited, the one-piece hollow carrier plate 30 may be inconvenient to process or assemble. This embodiment adopts a split design: multiple sub-carrier plates 30 (e.g., two L-shaped sub-carrier plates 30, or four strip-shaped sub-carrier plates 30, or one block-shaped sub-carrier plate B1 and one U-shaped sub-carrier plate B2) surround the unit to be molded 50 to form a complete support frame. The thickness of each sub-carrier plate 30 is equal to the depth d2 of the lower mold cavity, and a small gap (usually 0.05-0.2mm) is reserved between its inner surface and the outer surface of the unit to be molded 50. The advantages of the split carrier plate 30 are: the number and layout of the sub-carrier plates 30 can be flexibly adjusted according to the actual shape of the unit to be molded 50, without the need to process a dedicated carrier plate 30 for each shape of unit to be molded 50; at the same time, the sub-carrier plates 30 are small in size, simple to process, and have lower cost; they are also easier to operate when fixed. For example, for a rectangular unit 50 to be encapsulated, four long strip-shaped subcarrier plates 30 can be used to attach to the four sides respectively; for circular or irregular shapes, multiple small-sized subcarrier plates 30 can be used to surround it circumferentially.

[0043] As one possible implementation method, such as Figures 6 to 8 As shown, the unit to be encapsulated 50 and multiple subcarrier plates 30 are spliced ​​together using high-temperature resistant tape 40.

[0044] It should be noted that the high-temperature resistant tape 40 can be adhered to the top surfaces of the unit to be encapsulated 50 and the subcarrier plate 30, firmly connecting them into a single unit. The high-temperature resistant tape 40 can withstand the high temperatures (typically 175-200℃) during the encapsulation process without softening, peeling, or releasing volatile substances. Commonly used high-temperature resistant tapes 40 include polyimide tape and fiberglass tape. Using tape splicing eliminates the need for complex positioning holes or slots on the unit to be encapsulated 50 or the subcarrier plate 30, simplifying the operation, reducing costs, and facilitating disassembly, making it easy to separate the unit to be encapsulated 50 from the subcarrier plate 30 after encapsulation. The tape width can be selected according to the dimensions of the unit to be encapsulated 50 and the subcarrier plate 30, typically 5-15mm. The tape length should at least cover the entire splicing boundary to ensure sufficient connection strength.

[0045] As one possible implementation method, such as Figures 6 to 8 As shown, high-temperature resistant tape 40 is attached along the splicing edge of the unit to be encapsulated 50 and the subcarrier plate 30 to form a cofferdam structure around the unit to be encapsulated 50.

[0046] It should be noted that when the high-temperature resistant tape 40 is applied to the splicing edge, part of its width covers the edge of the unit to be encapsulated 50, and another part covers the edge of the subcarrier plate 30. Since the tape itself has a certain thickness (typically 0.05-0.15mm), it forms a raised dam structure after application. This dam structure effectively prevents molten encapsulant from seeping into the gap between the unit to be encapsulated 50 and the subcarrier plate 30 during the encapsulation process, preventing the encapsulant from contacting the pad C or contaminating the bottom surface of the substrate 21. Simultaneously, the dam structure further enhances the connection strength between the unit to be encapsulated 50 and the subcarrier plate 30, preventing relative displacement under the impact of the encapsulant flow, significantly improving the stability of the encapsulation process and the reliability of the finished product. The height of the dam structure is determined by the thickness and number of layers of tape. For example, the dam height formed by a single layer of tape is approximately 0.05-0.15mm. If a stronger anti-overflow effect is required, two layers of tape can be overlapped, and the dam structure height can reach 0.1-0.3mm.

[0047] As one possible implementation method, such as Figure 3 and Figure 7 As shown, the projected area of ​​the pad C on the standard molding die 10 is greater than the projected area of ​​the unit to be molded 50 on the standard molding die 10.

[0048] It should be noted that this embodiment further optimizes the structure of the pad C. When the projected area of ​​the pad C on the standard molding die 10 is larger than the projected area of ​​the unit to be molded 50 on the standard molding die 10, the pad C, in addition to providing thickness compensation, can also form an extended support area around the unit to be molded 50. This design can bring the following beneficial effects: First, it enhances the stability of the pad C at the bottom of the cavity. Because the pad C has a larger area, the contact area with the bottom surface of the mold cavity increases, making it less prone to sliding or shifting during the molding process, thus providing more reliable support for the unit to be molded 50. Second, it prevents the molding material from overflowing to the bottom of the unit to be molded 50. During molding, the molten molding material may penetrate to the bottom of the unit to be molded 50 under high pressure. With the area of ​​the pad C larger than the unit to be molded 50, its extended portion can block the molding material from flowing into the bottom of the unit to be molded 50, preventing the molded body from sticking to the pad C, and facilitating the subsequent removal of the pad C. Third, it improves the flatness of the bottom of the finished molded body. Because the pad C provides flat and continuous large-area support, the substrate 21 at the bottom of the unit to be encapsulated 50 is subjected to uniform force during the encapsulation process and is not easily deformed, thus ensuring the flatness of the bottom surface of the encapsulated product.

[0049] The area of ​​the backing plate C can be flexibly designed according to the size of the unit 50 to be molded. Optionally, the single-sided dimension of the backing plate C is 2-10mm larger than the single-sided dimension of the unit 50 to be molded. The specific value can be determined according to the mold cavity size and process requirements. For example, for a unit 50 to be molded with a size of 10mm×10mm, the area of ​​the backing plate C can be designed to be between 12mm×12mm and 20mm×20mm; for a unit 50 to be molded with a size of 5mm×5mm, the area of ​​the backing plate C can be designed to be between 7mm×7mm and 15mm×15mm. The outer extension of the backing plate C should not be too large, otherwise it may exceed the cavity range or cause interference, affecting mold closing; nor should it be too small, otherwise it will not be able to effectively prevent overflow.

[0050] As one possible implementation method, the pad C is made of a high-temperature resistant material.

[0051] It should be noted that the backing plate C directly contacts the bottom surface of the mold cavity during the molding process and bears the mold closing pressure under high temperature and high pressure. In this embodiment, the backing plate C can be made of the following materials: stainless steel (such as SUS304, SUS420) has excellent high temperature resistance and mechanical strength, the surface can be polished to a mirror finish, it will not scratch the mold, the cost is moderate, it is easy to process, and it is suitable for most R&D scenarios; cemented carbide has extremely high hardness and good wear resistance, it is suitable for scenarios with large-scale repeated use, and has an extremely long service life; ceramics (such as alumina, silicon nitride) are high temperature resistant, corrosion resistant, have a smooth surface, and the coefficient of thermal expansion is close to that of mold steel, making them suitable for high-end chip 22 packaging with high requirements for cleanliness and precision; high temperature resistant engineering plastics (such as polyimide, PEEK) are lightweight and will not scratch the mold, but their high temperature resistance is slightly poor, making them suitable for molding processes at lower temperatures (<200℃). Regardless of the material used, the lower surface of the backing plate C should be precision machined (e.g., ground or polished) to make its surface roughness comparable to that of the mold cavity surface (usually Ra≤0.2μm) to avoid scratching the mold cavity surface during the reverse compound molding process and to maintain the long service life of the mold.

[0052] In one possible implementation, S600, the molding compound is removed from the standard molding mold 10. The method further includes: S700, Post-curing treatment is performed on the molded body.

[0053] It should be noted that during the molding process, the molding compound undergoes initial curing within the mold, but incompletely cross-linked resin molecules and micro-air bubbles may remain inside. By subjecting the molded body to heat curing treatment (usually at 150-180℃ for 2-4 hours), the molding compound resin can be fully cross-linked and cured, eliminating residual air bubbles and significantly improving the density, adhesion, and mechanical strength of the molded body. Simultaneously, it enhances the molded body's temperature resistance, moisture resistance, and aging resistance.

[0054] The post-curing time depends on the thickness of the molded body and the type of molding compound: for thin molded bodies less than 0.5 mm thick, the post-curing time can be 2 hours; for molded bodies 0.5-1.0 mm thick, the post-curing time can be 3 hours; and for molded bodies thicker than 1.0 mm thick, the post-curing time can be 4 hours. The post-curing process can directly utilize existing ovens or curing furnaces without requiring additional specialized tooling. Process parameters can be flexibly adjusted according to the molding compound type, seamlessly integrating with standard molding processes.

[0055] As one possible implementation method, the standard molding die 10 is an injection molding die or a compression molding die.

[0056] It should be noted that when using an injection molding die, the backing plate C and the unit to be molded 50 are directly placed into the cavity. Utilizing the high-pressure melt filling characteristics of the injection molding process, the molding compound quickly and uniformly coats the chip 22, bonding wires, and other fine structures. Injection molding dies are suitable for most conventional molding scenarios. Their advantages include fast molding speed and high production efficiency, making them suitable for prototyping scenarios with a relatively large number of samples (e.g., dozens to hundreds of units).

[0057] When using compression molding molds, problems such as dead corners and residual air bubbles that easily occur in injection molding processes can be effectively solved. This is especially suitable for units 50 to be molded with high wire density and complex chip layouts. The filling process of compression molding molds is smoother; the molding compound, after preheating and softening, slowly fills the cavity under mold closing pressure, which helps to expel air and air bubbles. This is suitable for high-end chip 22 sample prototyping scenarios with stringent requirements for packaging quality and reliability. Neither type of mold requires customization; industry standard molds can be directly used, and the method in this application is fully compatible.

[0058] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0059] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for encapsulating a chip, characterized in that, The method includes: Provide at least one unit to be molded, the unit to be molded has completed the surface mount technology and wire bonding process, and the unit to be molded has a preset total product thickness; A standard molding die is provided, wherein the standard molding die has an internal cavity with a fixed total cavity depth; Obtain a backing plate, the thickness of which is equal to the total depth of the cavity minus the total thickness of the product; The pad and the unit to be molded are placed in the cavity of the standard molding mold, with the pad located below the unit to be molded; The unit to be encapsulated is encapsulated to form an encapsulated body; The encapsulated body is removed from the standard encapsulation mold, and the pad is removed to obtain the encapsulated finished product.

2. The chip encapsulation method according to claim 1, characterized in that, When the thickness of the substrate of the unit to be molded does not match the depth of the lower mold cavity of the standard molding die, providing at least one unit to be molded includes: A raw substrate is provided, the raw substrate including an effective area with chips mounted and an edge area without chips mounted; The edge region is cut and separated from the original substrate to obtain a substrate unit containing the effective region as the unit to be encapsulated. A carrier plate is provided, the thickness of which is equal to the depth of the lower mold cavity, and the overall planar dimensions of the carrier plate and the unit to be molded are matched with the planar dimensions of the cavity of the standard molding mold. The unit to be encapsulated is fixed to the carrier plate, so that the upper surface of the unit to be encapsulated is flush with the upper surface of the carrier plate; The step of placing the pad and the unit to be encapsulated into the cavity of the standard encapsulation mold includes: The pad and the carrier plate on which the unit to be sealed is fixed are placed in the cavity of the standard sealing mold, with the pad located below the unit to be sealed.

3. The chip encapsulation method according to claim 2, characterized in that, The carrier plate has a hollow area, and the unit to be encapsulated is fixed within the hollow area.

4. The chip encapsulation method according to claim 3, characterized in that, The carrier plate includes multiple sub-carrier plates, which are arranged around the periphery of the unit to be encapsulated.

5. The chip encapsulation method according to claim 4, characterized in that, The unit to be encapsulated is spliced ​​with multiple subcarrier plates using high-temperature resistant tape.

6. The chip encapsulation method according to claim 5, characterized in that, The high-temperature resistant tape is attached along the splicing edge between the unit to be sealed and the subcarrier plate to form a cofferdam structure around the unit to be sealed.

7. The chip encapsulation method according to any one of claims 1-6, characterized in that, The projected area of ​​the pad on the standard molding die is larger than the projected area of ​​the unit to be molded on the standard molding die.

8. The chip encapsulation method according to any one of claims 1-6, characterized in that, The pad is made of a high-temperature resistant material.

9. The chip encapsulation method according to any one of claims 1-6, characterized in that, After removing the molded body from the standard molding die, the method further includes: The encapsulated body undergoes post-curing treatment.

10. The chip encapsulation method according to any one of claims 1-6, characterized in that, The standard sealing mold is an injection sealing mold or a compression sealing mold.

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