Methods for forming reduced warpage electronic devices

Abstract

A method for forming an electronic device is provided. The method comprises the following steps: placing a substrate in a molding cavity of a molding mold, wherein at least one electronic component is mounted on the substrate; placing a molding material in the molding mold; melting the molding material by microwave radiation and applying a pressure to the molding material, thereby filling the molding cavity with the molten molding material and encapsulating the substrate and the at least one electronic component with the molten molding material; and curing the molding material by microwave radiation to solidify it into the mold cover.

Description

Technical Field

[0001] This application generally relates to semiconductor technology, and more specifically, to a method for forming electronic devices with reduced warpage. Background Technology

[0002] The semiconductor industry has consistently faced complex integration challenges as consumers demand smaller, faster, and higher-performing electronic devices, packing increasing functionality into single devices. Semiconductor packages are typically formed by first mounting electronic components onto a substrate via solder bumps, followed by forming a mold cap on the substrate to encapsulate the electronic components. The mold cap formation can involve a melting process for molten molding material and a solidification process for solidifying the molten molding material into the mold cap. Both melting and solidification processes can be performed by applying heating processes to the entire device. However, due to the mismatch in the coefficients of thermal expansion (CTE) between different materials within the device, the process can introduce warpage issues in the substrate and mold cap, which can adversely affect device performance and subsequent manufacturing processes.

[0003] Therefore, a method for forming electronic devices with reduced warpage is needed. Summary of the Invention

[0004] The purpose of this application is to provide a method for forming electronic devices with reduced warpage.

[0005] According to one aspect of this application, a method for forming an electronic device is provided. The method includes: placing a substrate within a molding cavity of a molding die, wherein at least one electronic component is mounted on the substrate; placing a molding material within the molding die; melting the molding material by microwave radiation and applying pressure to the molding material, thereby filling the molding cavity with the molten molding material and encapsulating the substrate and the at least one electronic component with the molten molding material; and curing the molding material by microwave radiation to solidify it into a mold cover.

[0006] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and do not limit the invention. Furthermore, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention. Attached Figure Description

[0007] The accompanying drawings, which are incorporated herein by reference, form part of this specification. Unless expressly indicated otherwise in the detailed description, the features shown in the drawings illustrate only some embodiments of this application, and not all embodiments thereof, and should not be construed as implying to the reader of this specification that all embodiments are possible.

[0008] Figures 1A to 1FThe various steps of a method for forming an electronic device according to a first embodiment of this application are shown.

[0009] Figures 2A to 2E The molding process of a method for forming an electronic device according to a second embodiment of this application is shown.

[0010] Figure 3 The various steps of a method for forming an electronic device according to a third embodiment of this application are shown.

[0011] Throughout the accompanying drawings, the same reference numerals will be used to refer to the same or similar parts. Detailed Implementation

[0012] The following detailed description of exemplary embodiments of this application takes into account the accompanying drawings, which form a part of the description. The drawings illustrate specific exemplary embodiments in which this application may be practiced. The detailed description, including the drawings, describes these embodiments in sufficient detail to enable those skilled in the art to practice this application. Those skilled in the art may further utilize other embodiments of this application and make logical, mechanical, and other changes without departing from the spirit or scope of this application. Therefore, the reader of the following detailed description should not interpret the description in a limiting sense, and the scope of the embodiments of this application is defined only by the appended claims.

[0013] In this application, unless otherwise expressly stated, the use of the singular includes the plural form. In this application, unless otherwise stated, the use of “or” means “and / or”. Furthermore, the use of the term “comprising” is not restrictive. Additionally, unless otherwise expressly stated, terms such as “element” or “assembly” cover both elements and assemblies comprising one unit and elements and assemblies comprising more than one sub-unit. Furthermore, the section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0014] As used herein, for ease of description, spatial relative terms such as “below,” “under,” “above,” “upper,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” and “side” may be used to describe the relationship between an element or feature and another element (or feature) or feature (or feature), as shown in the diagrams. In addition to the orientations depicted in the diagrams, the spatial relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein shall be interpreted accordingly. It should be understood that when an element is referred to as “connected to” or “coupled to” another element, the element may be directly connected to or coupled to the other element, or there may be intermediate elements present.

[0015] As mentioned above, a semiconductor package can be formed by first mounting electronic components onto a substrate via solder bumps, and then forming a mold cap on the substrate to encapsulate the electronic components. Generally, the formation of the mold cap may include the following steps: First, molding material can be placed within a molding die. Next, a heating process can be performed to preheat the molding die and the molding material. Pressure can also be applied to the molding material while it is heated to a high temperature, causing it to melt under pressure and high temperature. Next, the molten molding material can fill the molding cavity and encapsulate the substrate and the electronic components thereon. Next, the molding material is cured by a heating process and thus solidifies into the mold cap. During the process of melting and curing the molding material, it can be heated by a convection oven, which transfers heat to the entire device. The mold cap and substrate may deform due to a mismatch in the coefficient of thermal expansion (CTE) between the substrate and the mold cap, which arises from material differences between the substrate and the mold cap. Therefore, after the mold cap is formed, both the mold cap and the substrate may have warping issues, which can adversely affect device performance and subsequent manufacturing processes.

[0016] To address this problem, a method for forming an electronic device is provided. The method includes melting the molding material by applying microwave radiation and pressure to it to encapsulate a substrate and at least one electronic component. Additionally, microwave radiation is applied to solidify the molding material and solidify it into a mold cap. The microwave radiation heating process provides uniform and selective heating to the molding material, which reduces warpage problems in the formed mold cap and substrate. This improves device performance and facilitates subsequent manufacturing processes.

[0017] Figures 1A to 1F The various steps of a method for forming an electronic device according to a first embodiment of this application are shown.

[0018] like Figure 1AAs shown, substrate 100 is provided with embedded interconnects 101. Substrate 100 includes: a front surface that can serve as a platform for mounting electronic components 111; and a rear surface opposite the front surface. In some embodiments, substrate 100 may be made of silicon or other semiconductor materials, or may include a printed circuit board (PCB), a carrier substrate, a ceramic substrate, a laminated interposer, a lamination interposer, a lead frame, or other suitable substrate. In some embodiments, substrate 100 includes at least a nonpolar material, such as silicon, which is the predominant material of substrate 100. It should be noted that substrate 100 may also contain a small amount of polar material. For example, in this embodiment, substrate 100 may contain more than 99 wt.% nonpolar material and less than 1 wt.% polar material, which may help improve the structure and electrical performance of substrate 100. In some other embodiments, substrate 100 may contain less than 2 wt.%, 5 wt.%, or 10 wt.% polar material. Interconnects 101 may be formed between and through substrate 100. Therefore, electronic components 111 and other structures on one or both surfaces of the substrate 100 can be electrically coupled to each other to form an integrated electronic system, as will be described in more detail below. In some embodiments, a first set of conductive pads 102 may be formed on the front surface of the substrate 100 for mounting electronic components 111. It may also be understood that the first set of conductive pads 102 may be exposed portions of interconnects 101 formed within the substrate 100.

[0019] Next, solder paste is applied or attached to each of the first set of conductive pads 102 for mounting electronic component 111. More specifically, at least one electronic component 111 may include a second set of conductive pads 112 on its rear surface. Each of the second set of conductive pads 112 is aligned with one of the first set of conductive pads 102, with solder paste placed therebetween. At least one electronic component 111 may then be placed on the front surface of the substrate 100, with solder paste placed between the first set of conductive pads 102 and the second set of conductive pads 112. In some embodiments, electronic component 111 may include various types of electronic modules, such as semiconductor chips, resistors, capacitors, or other integrated circuit chips. For example, electronic component 111 may include a semiconductor die. Furthermore, as... Figure 1A As shown, one or more electronic components 111 are mounted on the substrate 100, and the electronic components 111 can have various sizes and be arranged in different layouts. In some embodiments, at least one electronic component 111 comprises at least one non-polar material. It can be understood that, similar to... Figure 1AThe substrate 100 shown may contain a small amount of polar material, such as an encapsulant or binder within the electronic component 111. For example, the electronic component 111 may contain more than 99 wt.%, 98 wt.%, 95 wt.%, or 90 wt.% of non-polar material and less than 1 wt.%, 2 wt.%, 5 wt.%, or 10 wt.% of polar material. In some embodiments, flux material may be further applied to the solder paste or dispensed onto the first set of conductive pads 102 to facilitate subsequent reflow soldering processes.

[0020] Next, a heating process can be applied to the substrate 100 to heat the solder paste, allowing the solder paste to be heated and reflowed to form solder bumps 105 between the first set of conductive pads 102 and the second set of conductive pads 112. The solder bumps 105 thus formed can form an electrical connection between at least one electronic component 111 and the substrate 100.

[0021] Next, a molding process is performed within a molding die to form a mold cover encapsulating the substrate 100 and at least one electronic component 111. More specifically, the molding process refers to a transfer molding process, as described in detail below.

[0022] like Figure 1B As shown, a molding die 120 is provided. In some embodiments, the molding die 120 may be formed of stainless steel, ceramic, copper, aluminum, or other types of materials. The molding die 120 includes a base platform 120a and a top cover 120b having a cavity. In this embodiment, a substrate 100 having at least one electronic component 111 is placed on the front surface of the base platform 120a. In some embodiments, the base platform 120a may have a venting channel fluidly connected to a vacuum source to apply a vacuum pressure to the substrate 100 when it is placed on the base platform 120a. The adsorption force generated by the vacuum pressure applied to the substrate 100 can reduce warping of the substrate 100 during subsequent molding processes. It should be noted that, for clarity, Figure 1A The substrate 100 shown in the figure, having at least one electronic component 111, can be Figure 1B The simplified structure is shown below. Figure 1BAs shown, a top cover 120b is positioned above a substrate platform 120a, with the cavity of the top cover 120b aligned with the substrate platform 120a. When the top cover 120b is attached to the substrate platform 120a, the substrate platform 120a and the top cover 120b together define a molding cavity 120e, and during the molding process, a substrate 100 having at least one electronic component 111 is accommodated within the molding cavity 120e. In some embodiments, the sidewalls of the molding cavity 120e of the top cover 120b are inclined relative to the front surface of the substrate platform 120a to facilitate the release (or detachment) of the molding die 120 from subsequently formed electronics. In some other embodiments, the molding cavity may have a cuboid shape, or any other suitable shape as required. It will be understood that the configuration of the molding cavity can be designed to accommodate or adapt to any structure of the substrate 100 and electronic component 111 that needs to be encapsulated.

[0023] Still referencing Figure 1B The molding die 120 may further include a loading chamber 120d, which is arranged adjacent to the molding cavity 120e and fluidly connected to the molding cavity 120e when the top cover 120b is attached to the base platform 120a. More specifically, a piston 120c may be arranged adjacent to the base platform 120a and is longitudinally movable relative to the base platform 120a. A piston cover 120f is movably connected to the piston 120c for mechanically supporting the piston 120c. Furthermore, a portion of the top cover 120b may be aligned with the piston 120c such that when the top cover 120b is attached to the base platform 120a, the top cover 120b, piston 120c, piston cover 120f, and base platform 120a together define the loading chamber 120d. During subsequent molding processes, the piston 120c may be movable relative to the base platform 120a, thereby reducing the volume of the loading chamber 120d.

[0024] Next, molding material 130 is placed within loading chamber 120d, more specifically, on the front surface of piston 120c. Molding material 130 may include polar materials, such as epoxy molding compounds (including epoxy resins) or other polymer composites, and a curing agent. Additionally, molding material 130 may be in the form of pellets, which allows for easy weighing or measurement in the desired quantity. Molding material pellets 130 may serve as raw material for forming a mold cap for encapsulating substrate 100 and at least one electronic component 111. In this embodiment, top cap 120b is positioned above base platform 120a and piston 120c, with channels between top cap 120b and base platform 120a and piston 120c to facilitate loading of molding material 130.

[0025] Next, as Figure 1CAs shown, after the molding material 130 is loaded into the loading chamber 120d, the top cover 120b moves toward the base platform 120a and the piston 120c to attach the top cover 120b to the base platform 120a. In some embodiments, the top cover 120b may be mechanically coupled to an actuator that automatically controls the top cover 120b to move up or down, or horizontally relative to the base platform 120a. In some other embodiments, the top cover 120b may be manually controlled, for example, by at least one manual turntable or other similar drive mechanism. In this way, the molding cavity 120e can be closed by the top cover 120b and the base platform 120a having a certain shape. It should be noted that a small gap may be created between the loading chamber 120d and the molding cavity 120e to define a fluid interface 121 through which the loading chamber 120d is fluidly connected to the molding cavity 120e.

[0026] Next, as Figure 1D As shown, the piston cap 120f is movable toward the top cap 120b to close the loading chamber 120d. Next, a microwave source is placed above the top surface of the molding die 120. Microwave radiation is then applied from the microwave source and passes through the molding die 120 to reach the molding material 130. Since the molding material 130 comprises a polar material, the dipoles within the polar molecules of the molding material 130 are sensitive to the electric field of the microwaves and can rotate to align themselves with the direction of the electric field. The electric field of the microwaves changes periodically, which causes the dipoles to rotate frequently. Therefore, as the dipoles attempt to follow the electric field, they may collide with each other, generating heat in the molding material 130. In this way, microwave radiation can be sustained for 30 seconds to 2 minutes to rapidly and sufficiently heat the molding material 130 to a temperature of approximately 150°C to 190°C (or preferably, to a temperature of approximately 165°C to 175°C), which facilitates its melting process. Because the molecules in nonpolar materials are insensitive to the electric field of microwaves, the substrate 100 and electronic components 111 may not be heated, or may be minimally heated, by microwave radiation when they are exposed to microwaves together with the molding material 130. Furthermore, the interconnects 101 embedded within the substrate 100 and the metal layers that may be included within the electronic components 111 reflect microwaves and generate virtually no heat. In this way, the molding material 130 is selectively heated by microwave radiation, which improves heating efficiency and also reduces warpage problems of the substrate 100 and at least one electronic component 111 mounted thereon. In some other embodiments, the microwave source may be placed near the loading chamber 120d, which provides more radiation directly to the molding material 130 and reduces the impact of the microwave radiation process on the substrate 100 and at least one electronic component 111 mounted thereon.

[0027] Furthermore, in this embodiment, the frequency can be varied. Figure 1DMicrowave radiation in the environment. By rapidly scanning the frequency range, the uniformity of microwave energy can be increased compared to microwave radiation at a fixed frequency. In some embodiments, microwave radiation is applied at a frequency between 1 GHz and 10 GHz.

[0028] In some other embodiments, piston 120c may include a heater that generates additional heat. This additional heat can raise the ambient temperature during the microwave irradiation process to reduce heat dissipation from the molding material 130 to the molding die 120. Furthermore, since piston 120c is in direct contact with the molding material 130, the additional heat can be transferred to the molding material 130 via convection. This allows the temperature of the molding material 130 to rise more rapidly and reduces the microwave energy required to heat the molding material 130 to a specific temperature during this step.

[0029] Next, as Figure 1E As shown, when microwave radiation is applied to the molding material 130, the piston 120c is moved toward the top cover 120b manually or automatically (e.g., by a driver) to reduce the volume of the loading chamber 120d, thereby enabling pressure to be applied within the loading chamber 120d where the molding material 130 is placed. The pressure within the loading chamber 120d can continuously increase as the piston 120c moves. It should be noted that in this embodiment, microwave radiation and pressure can be applied to the molding material 130 simultaneously. Under the increased pressure and high temperature, the spherical molding material 130 can melt into a liquid state. Alternatively, in some other embodiments, microwave radiation and pressure can be applied sequentially to melt the molding material 130. Then, the piston 120c continuously moves toward the top cover 120b to further increase the pressure within the loading chamber 120d, causing the molten molding material 130 to be injected from the loading chamber 120d into the molding cavity 120e through the fluid interface 121. Finally, the molding material 130 injected from the loading chamber 120d fills the molding cavity 120e, the molding material 130 covering the corresponding surface of at least one electronic component 111 and the front surface of the substrate 100, such as... Figure 1F As shown in the diagram, microwave radiation is continuously applied to the molding material 130 during the melting process of the molding material 130 and during the process of injecting the molding material 130 into and filling the molding cavity 120e. This ensures that the molding material 130 is maintained at a high temperature and remains in a liquid state before it completely encapsulates the substrate 100 and at least one electronic component 111.

[0030] Next, as Figure 1FAs shown, after the molten molding material 130 fills the molding cavity 120e and encapsulates the substrate 100 and at least one electronic component 111, a curing process is performed on the molding material 130 to solidify it into a mold cover 140. During the curing process, microwave radiation is continuously applied to the molding material 130, causing the epoxy resin and curing agent included in the molding material 130 to undergo a chemical reaction to form a cross-linked polymer. In some embodiments, the molten molding material 130 may be heated to a temperature of about 140°C to 180°C (or preferably, about 150°C) to solidify into the mold cover 140. Furthermore, the duration of microwave radiation application may be between 20 minutes and 2 hours to ensure sufficient curing of the molding material 130. In this embodiment, microwave radiation is applied at a variable frequency during the curing process. In some other embodiments, the curing process may include multiple curing steps sequentially performed on the molding material 130, and each of the multiple curing steps may have a different curing temperature.

[0031] In some other embodiments, the substrate platform 120a may include a heater that generates additional heat. This additional heat can raise the ambient temperature during the microwave curing process to reduce heat dissipation from the molding material 130 to the molding die 120. Furthermore, the microwave source may be positioned close to the molding cavity 120e and away from the loading chamber 120d, which allows more radiation to be directly supplied to the molding material 130 during the curing process. In this way, only a small amount of microwave radiation reaches the molding material 130 within the loading chamber 120d, thereby reducing the required microwave energy from the microwave source and improving curing efficiency.

[0032] In this embodiment, microwave radiation is continuously applied to heat the molding material 130 during the three stages of the entire molding process, namely the melting stage of the molding material 130 (in... Figure 1C (as shown in the figure) the injection stage in which molding material 130 is injected into molding cavity 120e (in Figure 1D (as shown in the diagram) and the curing stage of the molding material 130 (in Figure 1E (As shown in the diagram). In this way, all heating processes within the aforementioned stages can be performed using the same microwave radiation device without the need for an additional energy source. In some embodiments, the molding material 130 may be heated to different temperatures during each stage. To achieve this, the process parameters of microwave radiation in each stage (e.g., the power of the microwave source, the frequency of microwave radiation, the heating duration, etc.) can be adjusted independently, thereby easily adjusting the microwave energy applied to the molding material 130. Therefore, this significantly reduces processing costs and simplifies the manufacturing process. It should be noted that although the entire molding process is described in three stages for illustrative purposes, this molding process employs an integrated heating process throughout all stages of the molding process and uses the same microwave radiation device for heating.

[0033] For the formation of the mold cap 140, the continuous microwave irradiation process offers several advantages. First, it replaces the traditional heating process applied to the entire electronic device. By selectively heating the molding material 130 with microwave irradiation, warpage problems of the substrate 100 and electronic components 111 can be reduced, as the substrate 100 and electronic components 111 are hardly heated by microwave irradiation. Second, microwaves can penetrate the molding material 130 to supply energy and thus generate heat in a volumetric manner throughout the molding material 130. This allows for a more uniform heat distribution in the molding material 130, for example, from the surface of the molding material 130 to the interior, or across the entire molding cavity 120e. Third, after the molding material 130 has cured, greater fluidity and diffusivity can be achieved throughout the epoxy resin network structure within the formed mold cap 140, thereby significantly improving the uniformity of the mold cap structure through a greater degree of curing. Therefore, a lower curing temperature may be required to fully cure the molding material 130, thereby reducing energy consumption and improving the quality of the formed mold cap 140. Furthermore, because each photon has low energy, microwaves induce molecular rotation without breaking molecular bonds, which has minimal impact on the internal structure of electronic components. Additionally, microwave heating can be started and / or stopped quickly, shortening the heating duration.

[0034] In some embodiments, the material of the curing agent, the proportion of resin included in the molding material 130, and the proportion of the curing agent can be appropriately selected. Thus, after the resin and curing agent chemically react during the curing process, a polymer with a lower crosslinking density and longer chains can be produced. For example, the curing agent material may include an amine-based material. The proportion of resin included in the molding material 130 may be 5% to 10%, and the proportion of the curing agent included in the molding material 130 may be 5% to 7%. The polymer may exhibit a lower storage modulus, which allows the mold cap 140 to have a softer texture and reduced strain within it. Therefore, the mold cap 140 may have higher durability and extended service life to protect the encapsulated substrate 100 and at least one electronic component 111.

[0035] In some other embodiments, multiple microwave sources may be arranged around the molding die 120, more specifically, near the loading chamber 120d and the molding cavity 120e. The microwave sources near the loading chamber 120d and the molding cavity 120e may operate independently with different parameters during various stages of the molding process. For example, when the melting stage of the molding material 130 begins, the microwave source near the loading chamber 120d may be turned on to provide microwave energy to melt the molding material 130, while the microwave source near the molding cavity 120e may be turned off because the molding material 130 has not yet been injected into the molding cavity 120e. Similarly, when the curing stage of the molding material 130 begins, the microwave source near the molding cavity 120e may be turned on to provide microwave radiation, while the microwave source near the loading chamber 120d may be turned off because the molding material 130 within the loading chamber 120d is unnecessary for the formed mold cap 140. This can save energy consumption throughout the molding process and also make the molding process more efficient. In some alternative embodiments, the microwave source can be moved relative to the molding die 120 to apply microwave radiation to the molding material 130 at different locations during various stages of the molding process.

[0036] In some other embodiments, the molding die 120 may include a coating formed on the inner surfaces of the loading chamber 120d and the molding cavity 120e. The coating may include or be distributed with a polar material, said polar material including at least one polar material selected from the group consisting of silicon carbide, graphite, polar charcoal, or polar carbon. When microwave radiation is applied to the molding material 130, the coating may also be exposed to microwave radiation and may also absorb microwave energy. Thus, heat may be generated within the coating. Since the coating faces the molding material 130, the heat generated in the coating can be transferred to the molding material 130 via convection. This provides additional heat to the molding material 130 throughout various stages of the molding process. In this way, the molding material 130 can be heated by a hybrid heating mechanism combining direct microwave heating and convective heat transferred from the coating, resulting in high energy efficiency throughout the molding process and thus lower energy requirements for the microwave source. Furthermore, by applying lower microwave energy from the microwave source, the total heat generated within the device can be reduced, which can prevent or mitigate the burning effect caused by excessive microwave energy. Simply put, excess microwave energy that the molding material 130 cannot absorb can be collected by the coating and converted into heat, which in turn helps with various heating processes of the molding material 130 throughout the molding process.

[0037] Next, after the mold cap 140 is formed, the substrate 100 and at least one electronic component 111 encapsulated by the mold cap 140 can be removed from the molding die 120. In some embodiments, the top cover 120b may include an ejector pin inserted into one side of the top cover 120b. When the mold cap 140 is removed from the top cover 120b, the ejector pin may protrude from the top cover 120b and press against a peripheral portion of the substrate 100. In this way, the substrate 100 and at least one electronic component 111, together with the mold cap 140 formed thereon, can be pushed away from the top cover 120b, and thus demolded from the top cover 120b. In some embodiments, the top cover 120b may include two or more ejector pins inserted into both sides of the top cover 120b or at other locations on the top cover 120b to completely remove the mold cap 140 from the top cover 120b. For example, the ejector pin may press against the mold cap 140 instead of the substrate 100 itself.

[0038] Next, redundant portions of the solidified molding material 130, such as the molding material 130 solidified within the loading chamber 120d, can be removed from the mold cover 140 of the encapsulation substrate 100 and the electronic component 111. This allows for the formation of electronic devices with reduced warpage and lower manufacturing costs.

[0039] Figures 2A to 2E The various steps of the molding process of a method for forming an electronic device according to a second embodiment of this application are shown. Figures 2A to 2E The molding process shown (which is a compression molding process) can be: Figures 1B to 1F The process of replacing the molding process is shown in the figure.

[0040] like Figure 2A As shown, a molding die 220 is provided, comprising a lower die portion 220a and an upper die portion 220b movable relative to each other and jointly defining a molding cavity 220d. In this embodiment, a substrate 200 having at least one electronic component 211 is placed on the front surface of the lower die portion 220a. Both the substrate 200 and the at least one electronic component 211 may comprise primarily nonpolar materials. Furthermore, a piston 220c may be arranged through the lower die portion 220a and is longitudinally movable relative to the lower die portion 220a. A molding material 230 comprising a polar material is placed on the front surface of the piston 220c. In some embodiments, the piston 220c may be arranged within the central portion of the lower die portion 220a. Next, as... Figure 2B As shown, piston 220c moves toward upper mold portion 220b to push molding material 230 into molding cavity 220d. Next, a microwave source is placed above the top surface of molding die 220. Subsequently, microwave radiation is applied from the microwave source and passes through molding die 220 to reach molding material 230, as... Figure 2CAs shown. Because the molding material 230 comprises a polar material, it can absorb microwave energy to generate heat therein. In this way, the molding material 230 can be rapidly and sufficiently heated to a temperature of about 150°C to 190°C (or preferably, to a temperature of about 165°C to 175°C), which facilitates its melting process.

[0041] Next, as Figure 2D As shown, when microwave radiation is applied to the molding material 230, the upper mold portion 220b moves toward the lower mold portion 220a to reduce the volume of the molding cavity 220d, thereby applying pressure within the molding cavity 220d where the molding material 230 is placed. Under the increased pressure and high temperature, the molding material 230 can melt into a liquid state. Then, the upper mold portion 220b continues to move toward the lower mold portion 220a to further increase the pressure within the molding cavity 220d. Finally, the upper mold portion 220b is attached to the lower mold portion 220a, and the molding cavity 220d is filled with the molding material 230, covering the corresponding surface of at least one electronic component 211 and the front surface of the substrate 200, as shown. Figure 2E As shown in the figure.

[0042] During the melting process of the molding material 230 and the process of the molding material 230 filling the molding cavity 220d, microwave radiation is continuously applied to the molding material 230. This ensures that the molding material 230 is maintained at a high temperature and remains in a liquid state before it completely encapsulates the substrate 200 and at least one electronic component 211. Next, still referring to... Figure 2E After the molten molding material 230 fills the molding cavity 220d, a curing process is performed on the molding material 230 by microwave radiation to solidify it into a mold cover 240, thereby forming an electronic device. Further details of the molding process can be found in similar... Figures 1B to 1F The details of the molding process shown are not described in detail here.

[0043] In this embodiment, since the substrate 200 and electronic components 211 are hardly heated by microwave radiation, selectively heating the molding material 230 by microwave radiation can reduce warpage problems of the substrate 200 and electronic components 211. Furthermore, microwaves can penetrate the molding material 230 to supply energy, and thus heat can be generated in a volumetric manner throughout the molding material 230, resulting in a uniform heat distribution in the molding material 230. Moreover, microwave radiation is continuously applied to heat the molding material 230 during three stages of the molding process, namely the melting stage of the molding material 230 (in... Figure 2C (as shown in the diagram), the compression stage of the molding material 230 filling the molding cavity 220d (in Figure 2D (as shown in the diagram) and the curing stage of the molding material 230 (in Figure 2E(As shown in the figure). In this way, all the heating processes of the molding material 230 in the aforementioned stages can be carried out using a single microwave radiation device without the need for an additional energy source, which greatly saves process costs and simplifies manufacturing steps.

[0044] Figure 3 The various steps of a method for forming an electronic device according to a third embodiment of this application are shown.

[0045] like Figure 3 As shown, a plurality of electronic components 302 are provided. The electronic components 302 may include various types of electronic modules, such as semiconductor chips. The electronic components 302 are mounted onto a carrier substrate 300 via an adhesive layer 301. Next, a molding process can be performed to form a mold cap 310 on the carrier substrate 300, which encapsulates the plurality of electronic components 302. The molding process may be similar to... Figures 1B to 1F The transfer molding process shown, or Figures 2A to 2E The compression molding process is shown. Next, the adhesive layer 310 and the carrier substrate 300 are removed from the mold cover 310 and the electronic component 302. Next, solder bumps and / or interconnect layers can be formed on the exposed surface of the electronic component 302. Next, the electronic component 302 encapsulated by the mold cover 310 is individually divided into multiple independent units, each of which includes the electronic component 302 encapsulated by the mold cover 310, thereby forming multiple electronic devices. Therefore, mass production of electronic devices can be implemented, and the warpage of electronic devices is reduced, manufacturing costs are lower, and the manufacturing process is simplified, which is highly beneficial for semiconductor manufacturing.

[0046] Although the exemplary method for forming electronic devices of this application has been described in conjunction with the corresponding figures, those skilled in the art will understand that modifications and adaptations can be made to the method for forming electronic devices without departing from the scope of the invention.

[0047] Various embodiments have been described herein with reference to the accompanying drawings. However, it will be apparent that various modifications and alterations can be made thereto, and other embodiments can be implemented, without departing from the broader scope of the invention as set forth in the appended claims. Furthermore, other embodiments will be apparent to those skilled in the art upon consideration of the description and practice of one or more embodiments of the invention disclosed herein. Therefore, this application and the examples herein should be considered merely exemplary, and the true scope and spirit of the invention are indicated by the list of exemplary claims appended.

Claims

1. A method for forming an electronic device, characterized in that, The method includes: A substrate is placed in the molding cavity of a molding die, and at least one electronic component is mounted on the substrate; The molding material is placed inside the molding die; The molding material is melted by microwave radiation and pressure is applied to the molding material, thereby filling the molding cavity with the molten molding material and encapsulating the substrate and the at least one electronic component with the molten molding material; and The molding material is cured by microwave radiation to solidify it into a mold cover.

2. The method according to claim 1, characterized in that, The molding die further includes a loading chamber for containing the molding material before it is melted and filled into the molding cavity, wherein the loading chamber is fluidly connected to the molding cavity via a fluid interface and contains a piston that moves in response to an external pressing action.

3. The method according to claim 2, characterized in that, The step of placing the molding material within the molding die includes placing the molding material within the loading chamber; and the steps of melting the molding material by microwave radiation and applying pressure to the molding material include: The microwave radiation is applied to the molding material within the loading chamber; and When the microwave radiation is applied to the molding material, the piston is moved to reduce the volume of the loading chamber, thereby applying the pressure to melt the molding material, and the molten molding material is injected from the loading chamber into the molding cavity through the fluid interface.

4. The method according to claim 1, characterized in that, The molding die includes an upper mold portion and a lower mold portion that are movable relative to each other and jointly define the molding cavity.

5. The method according to claim 4, characterized in that, The step of placing the molding material within the molding die includes placing the molding material within the molding cavity; and the steps of melting the molding material by microwave radiation and applying pressure to the molding material include: The microwave radiation is applied to the molding material within the molding cavity; and When the microwave radiation is applied to the molding material, the upper mold portion moves toward the lower mold portion to reduce the volume of the molding cavity, thereby applying pressure to melt the molding material and filling the molding cavity with the molten molding material.

6. The method according to claim 1, characterized in that, The steps of melting the molding material by microwave radiation and applying pressure to the molding material are performed simultaneously.

7. The method according to claim 1, characterized in that, The microwave radiation is continuously applied during the steps of melting the molding material and curing the molding material.

8. The method according to claim 1, characterized in that, The molding material includes polar materials.

9. The method according to claim 1, characterized in that, The step of melting the molding material by microwave radiation includes applying the microwave radiation at a variable frequency.

10. The method according to claim 1, characterized in that, The step of curing the molding material by microwave radiation includes applying the microwave radiation at a variable frequency.

11. The method according to claim 1, characterized in that, The step of curing the molding material by microwave radiation includes: applying the microwave radiation to heat the molding material to a temperature between 140°C and 180°C.

12. The method according to claim 1, characterized in that, The step of curing the molding material by microwave radiation includes applying the microwave radiation for a duration between 20 minutes and 2 hours.

13. An electronic device, characterized in that, The electronic device is formed using the method according to any one of claims 1 to 12.

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