Chip plastic sealing method based on pre-vacuum cavity injection and chip

Abstract

The application discloses a chip plastic sealing method based on pre-vacuum cavity injection molding, which comprises the following steps: laying a large-size chip to be sealed on a substrate in a cavity of a lower mold box, and placing a back surface of the large-size chip on the substrate to perform substrate adsorption; covering an upper mold box on the lower mold box to form a plastic sealing cavity, and dividing the plastic sealing cavity into an upper cavity and a lower cavity according to the substrate; filling a gap between an inner wall of the lower cavity and the large-size chip with resin; performing one-time injection molding on the large-size chip through an injection molding hole arranged on the upper mold box; performing vacuumizing on the upper cavity; performing two-time injection molding on the large-size chip through the injection molding hole; opening the upper mold box, and stripping the large-size chip from the plastic sealing cavity to obtain a large-size chip after plastic sealing. The method makes the vacuumizing process more stable, reduces problems caused by uneven vacuum force, improves the stability of the production process, and reduces the defective product rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor processing, and particularly relates to a chip plastic packaging method based on pre-vacuum cavity injection molding and a chip. BACKGROUND

[0002] In the semiconductor packaging industry, automatic plastic packaging technology is widely used due to its high efficiency and accuracy. An important feature of this technology is to perform vacuum extraction on the mold cavity before injection molding to remove air and prevent defects such as air bubbles in the plastic package. However, there are technical challenges in processing large-size chip packaging products. The chip size of such products is relatively large and occupies a large part of the packaging product. When using conventional vacuum injection molding methods, due to the large size of the chip and the limitation of the mold cavity, the vacuum force is mainly concentrated on the surface of the chip, rather than being evenly distributed on the substrate. This causes the middle part of the substrate to be raised due to the vacuum suction force, and the solder wire may touch the upper cavity mold during the forming process, ultimately causing the problem of line collapse in the large-size chip packaging process. SUMMARY

[0003] Embodiments of the present application provide a chip plastic packaging method based on pre-vacuum cavity injection molding and a chip, aiming to solve the problem of line collapse in the large-size chip packaging process in the prior art method.

[0004] In a first aspect, embodiments of the present application disclose a chip plastic packaging method based on pre-vacuum cavity injection molding. The method includes laying a large-size chip to be plastic packaged on a substrate in a lower mold box cavity and placing a back surface of the large-size chip directly on the substrate for substrate adsorption; closing an upper mold box on the lower mold box to form a plastic packaging cavity, and dividing the plastic packaging cavity into an upper cavity and a lower cavity according to the substrate; filling a gap between the inner wall of the lower cavity and the large-size chip with resin; performing primary injection molding on the large-size chip through an injection molding hole provided in the upper mold box; performing vacuum extraction on the upper cavity; performing secondary injection molding on the large-size chip through the injection molding hole; opening the upper mold box and peeling the large-size chip from the plastic packaging cavity to obtain a plastic-packaged large-size chip.

[0005] Further, before laying the large-size chip to be plastic packaged on the substrate in the lower mold box cavity and placing the back surface of the large-size chip directly on the substrate for substrate adsorption, the method further includes immersing the large-size chip to be plastic packaged in a wetting agent for wet cleaning, and the wetting agent is configured in a mass ratio of 2:1:3:4 of solvent, acid, surfactant and water; and pre-cutting the large-size chip after wet cleaning to make the large-size chip meet the preset marked size.

[0006] Further, the one-shot injection molding uses epoxy plastic packaging material and a curing agent for plastic packaging, and the mass ratio of the epoxy plastic packaging material to the curing agent is 10:3.

[0007] Further, the two-shot injection molding uses polyimide material for plastic packaging.

[0008] Further, the upper cavity is vacuumized, including monitoring the vacuum degree inside the upper cavity by using a vacuum gauge to ensure that a predetermined vacuum degree standard value is reached; if the vacuum degree inside the upper cavity reaches the predetermined vacuum degree standard value, a stationary state is maintained to ensure that the resin fully fills the gap around the large-size chip and expels the air bubbles.

[0009] Further, before laying the large-size chip to be plastic-packaged on the substrate in the lower mold box cavity and placing the back surface of the large-size chip directly on the substrate for substrate adsorption, the method further includes pasting the large-size chip to one side surface of the substrate, and both side surfaces of the substrate are adhesive.

[0010] Further, the opening of the upper mold box and the peeling of the large-size chip from the plastic packaging cavity to obtain the plastic-packaged large-size chip include extending the probe of the de-chip machine into the gap between the large-size chip and the substrate and applying uniform stress to the other side surface of the large-size chip, so that the large-size chip is separated from the substrate.

[0011] Further, the substrate is made of glass fiber reinforced epoxy resin material.

[0012] Further, after the opening of the upper mold box and the peeling of the large-size chip from the plastic packaging cavity to obtain the plastic-packaged large-size chip, the method further includes setting an expected chip thickness value, judging whether the thickness of the large-size chip meets the stop packaging standard according to the expected chip thickness value; if the thickness of the large-size chip meets the stop packaging standard, the plastic packaging is stopped and the plastic packaging cavity is emptied.

[0013] In a second aspect, the embodiments of the present application also disclose a chip, which is prepared by using the chip plastic packaging method based on pre-vacuum cavity injection molding on a large-size chip to be plastic-packaged.

[0014] The above-mentioned embodiments of the scheme ensure the flatness of the substrate during packaging by adjusting the order of injection molding and vacuumizing, reduce the problem of solder line collapse caused by the arching of the substrate, and thus improve the overall quality of the packaged product. The improved process makes the vacuumizing process more stable, reduces the problems caused by uneven vacuum force, improves the stability of the production process, and reduces the rate of defective products. The line arc is not bent or exceeds the standard, effectively avoiding the risk of short circuit caused by the line arc problem, and improving the electrical performance and reliability of the product. By controlling the injection time in sections and starting vacuumizing in the middle of the injection, the flow and solidification of the injection material can be better controlled, and the accuracy and repeatability of the injection process are improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0016] Fig. 1 A flowchart of a chip plastic packaging method based on pre-vacuum cavity injection molding is provided for the embodiments of the present application.

[0017] Fig. 2 A structure diagram in a plastic packaging cavity is provided for the embodiments of the present application.

[0018] Fig. 3 Another structure diagram in a plastic packaging cavity is provided for the embodiments of the present application.

[0019] Reference Signs:

[0020] 1, large-size chip; 2, upper mold box; 3, lower mold box; 4, substrate; 5, upper cavity; 6, lower cavity; 8, resin filling layer. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0022] It should be understood that the terms "comprising" and "including" as used in the specification and the appended claims indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0023] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should be further understood that the term "and / or" as used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0025] As Figs. 1-3 shown, Fig. 1 A method flow chart of the method of the chip plastic packaging method based on the pre-vacuum cavity injection molding. The method provided by the embodiment is the chip plastic packaging method based on the pre-vacuum cavity injection molding, wherein the method comprises steps S110 to S170.

[0026] S110, lay the large-size chip 1 to be plastic-packaged on the substrate 4 in the cavity of the lower mold box 3 and place the back surface of the large-size chip 1 directly on the substrate 4 for substrate 4 adsorption.

[0027] S120, cover the upper mold box 2 on the lower mold box 3 to form a plastic packaging cavity, and divide the plastic packaging cavity into an upper cavity 5 and a lower cavity 6 according to the substrate 4.

[0028] S130, resin fill the gap between the inner wall of the lower cavity 6 and the large-size chip 1.

[0029] S140, one injection molding of the large-size chip 1 through the injection hole arranged on the upper mold box 2.

[0030] S150, vacuumize the upper cavity 5.

[0031] S160, two injection moldings of the large-size chip 1 through the injection hole.

[0032] S170, open the upper mold box 2 and peel off the large-size chip 1 from the plastic packaging cavity to obtain the large-size chip 1 after plastic packaging.

[0033] In actual use scenarios, in the field of semiconductor packaging, especially when handling large-size chips 1 using automatic plastic packaging technology, the packaging quality and efficiency are affected: when the chip size is large and occupies most of the space of the cavity, the action point of the vacuum force is mainly concentrated on the chip surface. Due to the area of the chip being much larger than the substrate 4, the distribution of the vacuum force on the chip is much more uniform than on the substrate 4, resulting in a smaller vacuum force on the substrate 4. This uneven force distribution causes the middle part of the substrate 4 to be uplifted, while the edge part cannot move upward due to the constraint of the mold, causing the middle part of the substrate 4 to be uplifted. Due to the limited cavity space, the distance between the chip and the cavity wall is small, and the air flow is limited, which will affect the vacuum effect. During the vacuum process, the air in the cavity is difficult to quickly exhaust, resulting in insufficient vacuum degree, further exacerbating the uplift of the middle part of the substrate 4. The substrate 4 material usually has a certain flexibility, and when subjected to uneven force, it is easy to deform. The thickness and material elastic modulus of the substrate 4 also affect the degree of deformation under the action of the vacuum force. Due to the uplift of the middle part of the substrate 4, the height of the wire arc may be reduced, increasing the risk of contact with the upper cavity 5 mold. The contact of the wire arc with the mold will cause the wire arc to deform or even break, causing wire collapse defects. In large-size chip 1 packaging, the layout and shape design of the wire are particularly important. If the wire design is unreasonable, it is more likely to cause problems when the substrate 4 is uplifted. The design of the upper cavity 5 mold may not take into account the characteristics of the large-size chip 1, which may cause the distance between the mold and the wire to be too small, increasing the risk of contact. The uplift of the substrate 4 may cause changes in the flow path of the packaging material, affecting the filling effect of the packaging material, resulting in voids or bubbles. The uplift of the substrate 4 may cause uneven stress distribution inside the package, affecting the long-term reliability of the package.

[0034] The embodiment of the present scheme can effectively solve the problems encountered in the automatic plastic packaging process of large-size chips 1. The large-size chips 1 are laid flat on the substrate 4 in the cavity of the lower mold box 3, and the chip back surface is directly placed on the substrate 4 for substrate 4 adsorption. This step is the basis of the plastic packaging process, ensuring that the chip is correctly placed and fixed on the substrate 4, preparing for the subsequent steps. Cover the upper mold box 2 on the lower mold box 3 to form a plastic packaging cavity, and divide it into an upper cavity 5 and a lower cavity 6. This step creates a closed space required for plastic packaging, preparing for resin filling and injection molding. The gap between the inner wall of the lower cavity 6 and the chip is filled with resin. This step helps to reduce the air trapped between the chip and the cavity, preparing for one-shot injection, and also helps to improve the structural integrity of the plastic package. The chip is one-shot injected through the injection hole of the upper mold box 2. The purpose of one-shot injection is to preliminarily fix the chip and lay the foundation for subsequent vacuum extraction and two-shot injection. By vacuumizing the upper cavity 5, the problem of the middle part of the substrate 4 bulging can be effectively reduced, because the chip has been partially fixed by the one-shot resin at this time. The chip is two-shot injected through the injection hole. Two-shot injection further fills the cavity, ensuring the integrity of the plastic package and the complete fixation of the chip. Open the upper mold box 2 and peel off the plastic packaged chip from the plastic packaging cavity. Complete the plastic packaging process and get the final product. The peeling process needs to be operated carefully to avoid damage to the chip or plastic package. Through one-shot injection and two-shot injection, the chip is gradually fixed, and the deformation of the substrate 4 is reduced. Vacuumizing the upper cavity 5 before two-shot injection reduces the risk of the middle part of the substrate 4 bulging. Resin filling in the lower cavity 6 helps to improve the uniformity and structural strength of the plastic package.

[0035] In summary, to solve the problems encountered during the automatic plastic packaging process of large-size chips 1, resin filling is performed first, followed by step-by-step injection molding, which can gradually fix the chips and reduce the deformation of the substrate 4 caused by uneven vacuum force. After the first injection molding, the chips have been partially fixed, which helps to reduce the phenomenon of the middle part of the substrate 4 bulging during vacuum extraction. Vacuum extraction is performed on the upper cavity 5 before the second injection molding, which can ensure that there is almost no air inside the cavity during the flow of the injection material, thereby avoiding the generation of air bubbles in the plastic package. By vacuum extraction in the upper cavity 5, the bulging of the middle part of the substrate 4 caused by uneven vacuum force is reduced, and the problem of wire collapse caused by the contact of the wire arc with the upper cavity 5 mold is avoided. The gap between the inner wall of the lower cavity 6 and the chip is filled with resin to form a resin filling layer 8, which can ensure that the air between the chip and the substrate 4 is effectively excluded. Resin filling helps to improve the density of the plastic package, reduce the problem of air bubbles caused by air being trapped, and also provides certain support for the chip, reducing the risk of deformation of the substrate 4. By pre-fixing the chip through the first injection molding, the force on the substrate 4 during the subsequent vacuum extraction process is more uniform, thereby reducing the phenomenon of the middle part of the substrate 4 bulging. Through resin filling, the gap between the chip and the cavity wall is reduced, the air flow is improved, the vacuum extraction process is more effective, and the problem of air bubbles caused by air being trapped is reduced. Since the deformation of the substrate 4 is reduced, the wire arc of the wire will not contact the upper cavity 5 mold, thereby avoiding the problem of wire collapse and improving the quality and reliability of the wire. By adjusting the order of injection molding and vacuum extraction, the flatness of the substrate 4 during packaging is ensured, and the problem of wire collapse caused by the arching of the substrate 4 is reduced, thereby improving the overall quality of the packaged product. The improved process makes the vacuum extraction process more stable, reduces the problems caused by uneven vacuum force, improves the stability of the production process, and reduces the rate of defective products. The wire arc is not bent or exceeds the standard, effectively avoiding the risk of short circuit caused by the wire arc problem, improving the electrical performance and reliability of the product. By controlling the injection time in stages and starting vacuum extraction in the middle of the injection, the flow and solidification of the injection material can be better controlled, improving the accuracy and repeatability of the injection process. The improvement scheme reduces the rework and waste caused by the arching of the substrate 4 and the wire problem, improves the production efficiency, and reduces the production cost. This scheme is suitable for packaging large-size chips 1, especially for products with a high chip area ratio, which can effectively solve the problems in traditional packaging processes. The improvement measures can be adjusted on the existing automatic plastic packaging equipment without the need for large-scale equipment replacement, and are easy to implement and promote. In summary, this scheme not only improves the quality and production efficiency of the packaged product, but also reduces the production cost, providing a more efficient and reliable solution for the semiconductor packaging field.

[0036] Further, before laying the large-size chip 1 to be encapsulated on the substrate 4 in the cavity of the lower mold box 3 and placing the back surface of the large-size chip 1 directly on the substrate 4 for substrate 4 adsorption, the method further comprises immersing the large-size chip 1 to be encapsulated in the infiltrant for rinsing, and the infiltrant is configured in a mass ratio of 2:1:3:4 of solvent, acid, surfactant and water; and the rinsed large-size chip 1 is pre-cut to make the large-size chip 1 conform to the preset marked size.

[0037] Specifically, in order to ensure the cleanliness and size accuracy of the large-size chip 1 before encapsulation, improve the adhesion between the chip and the resin, avoid delamination and falling off, and reduce the packaging problems caused by inconsistent chip sizes, the large-size chip 1 is immersed in the infiltrant configured in a certain proportion before being placed on the substrate 4. The composition of the infiltrant includes solvent, acid, surfactant and water, and this mixture can effectively remove grease, dust and other contaminants on the surface of the chip. The rinsing process can ensure the cleanliness of the chip surface, thereby improving the adhesion between the encapsulation material and the chip and reducing the possibility of air bubbles and delamination in the encapsulation body. The pre-cut large-size chip 1 after rinsing ensures that the size of each chip conforms to the preset marked size. Through accurate cutting, the correct placement of the chip on the substrate 4 can be ensured, and packaging problems caused by size inconsistency can be avoided, such as uneven encapsulation, glue overflow or wire problems. The solvent, acid, surfactant and water are configured in a mass ratio of 2:1:3:4 to make the infiltrant. The large-size chip 1 to be encapsulated is immersed in the infiltrant for thorough rinsing to ensure surface cleanliness. After rinsing is completed, the chip is taken out of the infiltrant and dried to remove excess infiltrant. The dried chip is cut according to the preset marked size using a precision cutting device. The pre-cut and dried large-size chip 1 is laid on the substrate 4 in the cavity of the lower mold box 3, ensuring that the back surface of the chip is placed directly on the substrate 4 for substrate 4 adsorption. Through these steps, not only the technical difficulties of the large-size chip 1 in the automatic encapsulation process are solved, but also the overall quality and reliability of the product are improved through rinsing and accurate cutting.

[0038] Further, the first injection molding uses epoxy encapsulation material and curing agent for encapsulation, and the mass ratio of the epoxy encapsulation material to the curing agent is 10:3.

[0039] Further, the second injection molding uses polyimide material for encapsulation.

[0040] Further, the upper cavity 5 is vacuumed, including using a vacuum gauge to monitor the vacuum degree inside the upper cavity 5 to ensure that the predetermined vacuum degree standard value is reached; if the vacuum degree inside the upper cavity 5 reaches the predetermined vacuum degree standard value, the state is kept static to ensure that the resin fills the gaps around the large-size chip 1 and expels air bubbles.

[0041] Specifically, the material selection for primary and secondary injection molding and the vacuum extraction process are specified in detail. Here is a detailed explanation of these steps and their role in the encapsulation process: Epoxy encapsulation material is a commonly used semiconductor packaging material, widely used due to its excellent electrical insulation, chemical stability and mechanical strength. The curing agent is used to react with the epoxy encapsulation material to harden it into a solid state. The mass ratio is 10:3, which is optimized to ensure that the encapsulation material has good performance after curing. Polyimide is a high-performance polymer with excellent heat resistance, chemical resistance and mechanical properties. Using polyimide material in secondary injection molding can provide an additional protective layer, enhancing the overall performance of the package, especially in high temperature or harsh environments. During the vacuum extraction process, a vacuum gauge is used to monitor the vacuum level inside the upper cavity 5 in real time, ensuring that it reaches the predetermined vacuum level standard value. This step is crucial to ensure the quality of encapsulation, as appropriate vacuum level can effectively remove air and bubbles inside the cavity, preventing defects in the encapsulated body. After the vacuum level inside the upper cavity 5 reaches the predetermined standard value, it is kept stationary for a period of time, ensuring that the resin fully fills the voids around the large-size chip 1 and expels any existing bubbles. This process helps the resin flow and penetrate better, resulting in a denser and more uniform encapsulated body. Mix the epoxy encapsulation material and curing agent according to the ratio. Pour the mixed encapsulation material into the lower cavity 6 through the injection hole, covering the large-size chip 1. After primary injection is completed, perform vacuum extraction. After the vacuum level reaches the predetermined standard and remains stationary, use polyimide material for secondary injection. Before secondary injection, use a vacuum gauge to monitor the vacuum level of the upper cavity 5. After reaching the predetermined vacuum level, keep it stationary to ensure resin filling and bubble expulsion. Through these meticulous steps, the problems encountered during the encapsulation of large-size chips 1 can be effectively solved, improving the quality and reliability of the package. In actual operation, these steps may need to be further optimized through experiments to ensure optimal production efficiency and product performance.

[0042] Further, before laying the large-size chip 1 to be encapsulated on the substrate 4 in the cavity of the lower mold box 3 and placing the back surface of the large-size chip 1 directly on the substrate 4 for substrate 4 adsorption, the method further comprises pasting the large-size chip 1 to one side surface of the substrate 4, both side surfaces of the substrate 4 having adhesion.

[0043] Further, opening the upper mold box 2 and peeling the large-size chip 1 from the encapsulation cavity to obtain the encapsulated large-size chip 1 comprises inserting the probe of the peeling machine into the gap between the large-size chip 1 and the substrate 4 and applying uniform stress to the other side surface of the large-size chip 1, so that the large-size chip 1 is separated from the substrate 4.

[0044] Specifically, before placing the large-size chip 1 on the substrate 4, the chip is first adhered to one side surface of the substrate 4. This approach ensures that the chip is securely fixed on the substrate 4 during the molding process, preventing poor packaging due to movement or tilting. Both side surfaces of the substrate 4 are adhesive, providing double-sided fixation for the chip, increasing the stability and reliability of the fixation. After the molding process is completed, the molded chip needs to be peeled off from the substrate 4. This step is completed by a debonder. The probe of the debonder extends into the gap between the large-size chip 1 and the substrate 4, which is a precise operation that needs to ensure that the probe does not damage the chip or the substrate 4. The probe applies uniform stress to the other side surface of the large-size chip 1, which is to smoothly separate the chip and the substrate 4, avoiding chip damage caused by uneven stress. Uniform stress can reduce the mechanical stress on the chip during the peeling process, improving the yield of the product. Apply an appropriate amount of adhesive to one side surface of the substrate 4. Adhere the back surface of the large-size chip 1 to the substrate 4, ensuring accurate chip positioning. Follow the previously described steps for molding, including one-shot injection, vacuum extraction, and two-shot injection. After molding is complete, move the device to the debonder position. Operate the debonder to precisely extend the probe into the gap between the chip and the substrate 4. Slowly apply uniform stress until the chip is smoothly peeled off from the substrate 4. These steps not only ensure the stable fixation of the chip during the molding process, but also provide an efficient and safe chip peeling method, thereby improving the automation level and production efficiency of the entire packaging process. In practical applications, these steps may need to be optimized through multiple trials to ensure optimal operation effect and product quality.

[0045] Further, the substrate 4 is made of glass fiber reinforced epoxy resin material.

[0046] Further, after opening the upper mold box 2 and peeling the large-size chip 1 in the molding cavity to obtain the molded large-size chip 1, the method further comprises setting an expected chip thickness value, determining whether the thickness of the large-size chip 1 meets the stop molding standard according to the expected chip thickness value; if the thickness of the large-size chip 1 meets the stop molding standard, stop molding and empty the molding cavity.

[0047] Specifically, the selection of substrate 4 material and the control of chip thickness after encapsulation are specified in detail in the process flow. The detailed explanation of these steps and their role in the encapsulation process are as follows. Glass fiber reinforced epoxy resin material has good mechanical strength, heat resistance and electrical insulation, and is suitable for use as a substrate 4 material for semiconductor packaging. The selection of this material helps to improve the stability of the substrate 4, better support the large size chip 1 during encapsulation, and resist the stress caused by vacuum extraction and injection. During encapsulation, a desired chip thickness value is set as a quality control standard. This value is based on product design requirements to ensure that the encapsulated chip meets specific thickness specifications. After encapsulation is complete, the actual thickness of the large size chip 1 is detected by measuring equipment (such as a thickness gauge). If the actual thickness meets the preset stop encapsulation standard, it means that the encapsulation process is successful and the operation can be stopped. Once the chip thickness meets the standard, the encapsulation operation is stopped to avoid over-encapsulation, which can cause the chip to be too thick or deformed. The encapsulation cavity is emptied to prepare for the next encapsulation process and ensure that there is no residual resin or other substances in the cavity. The substrate 4 is prepared using glass fiber reinforced epoxy resin material and ensuring that the substrate 4 surface is smooth and clean. Encapsulation is performed according to established steps, including chip pasting, injection, vacuum extraction, etc. After encapsulation is complete, the chip thickness is detected using measuring equipment and compared with the expected thickness value. If the chip thickness meets the standard, the encapsulation equipment is turned off and the encapsulation cavity is emptied. If the chip thickness does not meet the standard, the encapsulation parameters are adjusted and the encapsulation is performed again. Through these steps, not only the stability and reliability of the substrate 4 during encapsulation are ensured, but also the quality of the final product is guaranteed by precisely controlling the chip thickness. In actual production, these control measures help to improve automation, reduce human error, and improve production efficiency and product consistency.

[0048] In a second aspect, the present case discloses a chip, a large size chip 1 is encapsulated by the above-mentioned chip encapsulation method based on pre-vacuum cavity injection to prepare a large size chip 1 to be encapsulated.

[0049] The chip plastic sealing method based on pre-vacuum cavity injection molding and the chip prepared by the method are disclosed. The method comprises the following steps: laying a large-size chip 1 to be sealed on a substrate 4 in a cavity of a lower mold box 3 and placing a back surface of the large-size chip 1 directly on the substrate 4 for substrate 4 adsorption; covering an upper mold box 2 on the lower mold box 3 to form a plastic sealing cavity, and dividing the plastic sealing cavity into an upper cavity 5 and a lower cavity 6 according to the substrate 4; filling a gap between an inner wall of the lower cavity 6 and the large-size chip 1 with resin; performing one-time injection molding on the large-size chip 1 through an injection hole arranged on the upper mold box 2; performing vacuumization on the upper cavity 5; performing two-time injection molding on the large-size chip 1 through the injection hole; opening the upper mold box 2 and peeling the large-size chip 1 from the plastic sealing cavity to obtain a large-size chip 1 after plastic sealing. The above scheme effectively solves the problems encountered by the large-size chip 1 in the automatic plastic sealing process through the innovative step-by-step injection molding and pre-vacuum cavity injection molding technology, improves the packaging quality and production efficiency, and optimizes the plastic sealing process flow, so that the whole process is more automated and controllable, reduces the influence of human factors, and improves the stability of the process.

[0050] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A chip plastic packaging method based on pre-vacuum cavity injection molding, characterized in that, The method comprises the following steps: laying the large-size chip to be encapsulated on a substrate in a cavity of a lower mold box and placing a back surface of the large-size chip directly on the substrate for substrate adsorption; covering an upper mold box on the lower mold box to form an encapsulation cavity, and dividing the encapsulation cavity into an upper cavity and a lower cavity according to the substrate; resin filling a gap between an inner wall of the lower cavity and the large-size chip; one-shot injection molding of the large-size chip through an injection hole arranged on the upper mold box; vacuumizing the upper cavity; two-shot injection molding of the large-size chip through the injection hole; opening the upper mold box and peeling the large-size chip from the encapsulation cavity to obtain an encapsulated large-size chip.

2. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 1, characterized in that, Before the step of laying the large-size chip to be encapsulated on a substrate in a cavity of a lower mold box and placing a back surface of the large-size chip directly on the substrate for substrate adsorption, the method further comprises: immersing the large-size chip to be encapsulated in a wetting agent for wetting, wherein the wetting agent is configured by a solvent, an acid, a surfactant and water in a mass ratio of 2:1:3:4; pre-cutting the wetted large-size chip to make the large-size chip meet a preset marking size.

3. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 1, characterized in that, The one-shot injection molding is performed by using epoxy encapsulation material and a curing agent, and a mass ratio of the epoxy encapsulation material to the curing agent is 10:

3.

4. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 1, characterized in that, The two-shot injection molding is performed by using a polyimide material.

5. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 1, wherein, The step of vacuumizing the upper cavity comprises: monitoring a vacuum degree inside the upper cavity by using a vacuum gauge to ensure that a predetermined vacuum degree standard value is reached; if the vacuum degree inside the upper cavity reaches the predetermined vacuum degree standard value, keeping a stationary state to ensure that the resin fully fills a gap around the large-size chip and discharges air bubbles.

6. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 3, characterized in that, Before the step of laying the large-size chip to be encapsulated on a substrate in a cavity of a lower mold box and placing a back surface of the large-size chip directly on the substrate for substrate adsorption, the method further comprises: adhering the large-size chip to one side surface of the substrate, and both side surfaces of the substrate are adhesive.

7. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 6, characterized in that, The step of opening the upper mold box and peeling the large-size chip from the encapsulation cavity to obtain an encapsulated large-size chip comprises: extending a probe of a peeling machine into a gap between the substrate and the lower mold box and applying uniform stress to the other side surface of the large-size chip, so that the substrate and the large-size chip are separated from the lower mold box.

8. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 6, characterized in that, The substrate is made of glass fiber reinforced epoxy resin material.

9. The pre-vacuum cavity injection-based chip plastic packaging method according to claim 5, wherein, After the step of opening the upper mold box and peeling the large-size chip from the encapsulation cavity to obtain an encapsulated large-size chip, the method further comprises: setting an expected chip thickness value, and determining whether the thickness of the large-size chip meets a stop encapsulation standard according to the expected chip thickness value; if the thickness of the large-size chip meets the stop encapsulation standard, stopping encapsulation and emptying the encapsulation cavity.

10. A chip, characterized by The chip is prepared by using the chip encapsulation method based on pre-vacuum cavity injection molding according to any one of claims 1-9.

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