Three-sided metal encapsulation packaging structure and preparation method thereof

Abstract

The present invention provides a packaging structure with metal encapsulation on three sides and a preparation method thereof. The packaging structure is formed by half-cutting, electroplating, full-cutting, anti-oxidation and other processes, and the three sides of the packaging structure are electroplated with metal encapsulation, which can enable the packaging structure to achieve multi-directional shielding and unidirectional transmission of internal signals, and improve the heat dissipation of the packaging structure and the air tightness of the packaging, thereby improving product performance.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and in particular to a three-sided metal encapsulation packaging structure and a preparation method thereof. Background Art

[0002] With the development of electronic products, semiconductor technology has been widely used in the manufacture of memory, central processing unit (CPU), liquid crystal display device (LCD), light emitting diode (LED), laser diode and other devices or chipsets. Since electronic components such as semiconductor components, micro-electromechanical components (MEMS) or optoelectronic components have tiny and delicate circuits and structures, in order to avoid dust, acid and alkali substances, moisture and oxygen from polluting or corroding electronic components, thereby affecting their reliability and life, packaging technology is required to provide the above electronic components with power distribution, signal distribution, heat dissipation, protection and support and other functions.

[0003] After the semiconductor chip is packaged to form a packaging structure, the packaging structure must be connected or assembled with other electrical components depending on the usage. However, the existing packaging structure has poor heat dissipation and packaging airtightness, and cannot achieve multi-directional shielding and unidirectional transmission of internal signals, which in turn affects product performance.

[0004] Therefore, a new packaging structure is urgently needed to overcome the shortcomings of the above packaging structure. Summary of the invention

[0005] The purpose of the present invention is to provide a three-sided metal-encapsulated packaging structure and a preparation method thereof, which can improve the heat dissipation of the packaging structure and the airtightness of the packaging, and can realize multi-directional shielding and unidirectional transmission of internal signals, thereby improving product performance.

[0006] In order to achieve the above-mentioned object, the present invention provides a preparation method of a three-sided metal-encapsulated packaging structure, comprising the following steps: (1) providing a plastic-encapsulated product to be processed, the plastic-encapsulated product to be processed comprising a carrier, a plastic-encapsulated body is provided on the carrier, at least one electronic component is encapsulated in the plastic-encapsulated body, and the electronic component has at least one pin on a side close to the carrier; (2) half-cutting the plastic-encapsulated body in a first direction from a side away from the pin; (3) electroplating the plastic-encapsulated product to be processed to form metal walls on both sides of the half-cut cut and a metal cover on the first surface of the plastic-encapsulated body; (4) filling the cut with a filler; (5) removing the carrier and processing the second surface of the plastic-encapsulated body to expose the top of the pin to the plastic-encapsulated body, the second surface being opposite to the first surface; (6) fully cutting the plastic-encapsulated body in a second direction, the second direction being perpendicular to the first direction; (7) removing the filler to obtain at least one three-sided metal-encapsulated packaging structure.

[0007] In order to achieve the above-mentioned purpose, the present invention also provides a three-sided metal-encapsulated packaging structure, comprising: a plastic package body, a first surface of the plastic package body is coated with a metal cover body, and two opposite sides of the plastic package body are coated with metal walls; at least one electronic component is plastic-encapsulated in the plastic package body, and a side of the electronic component away from the metal cover body has at least one pin, and the top of the pin is exposed to the second surface of the plastic package body, and the second surface is opposite to the first surface.

[0008] The advantages of the present invention are: the preparation method of the packaging structure with metal encapsulation on three sides of the present invention utilizes half-cutting, electroplating, full-cutting, anti-oxidation and other processes to form a packaging structure with metal encapsulation on three sides that is electroplated, which can enable the packaging structure to achieve multi-directional shielding and unidirectional transmission of internal signals, and improve the heat dissipation of the packaging structure and the air tightness of the packaging, thereby improving product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 , a schematic diagram of the steps of the method for preparing a packaging structure with metal encapsulation on three sides of the present invention;

[0011] Figure 2 to Figure 9 , a process flow chart of an embodiment of a method for preparing a packaging structure with metal encapsulation on three sides of the present invention;

[0012] Figures 10A-10B , a three-dimensional diagram of an embodiment of a three-sided metal encapsulation packaging structure of the present invention. DETAILED DESCRIPTION

[0013] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. The directional terms mentioned in the present invention, such as: up, down, left, right, front, back, inside, outside, side, etc., are only with reference to the directions of the accompanying drawings. The embodiments described below with reference to the accompanying drawings and the directional terms used are exemplary and are only used to explain the present invention, and should not be construed as limitations on the present invention. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0014] See also Figure 1 , is a schematic diagram of the steps of the preparation method of the three-sided metal-encapsulated packaging structure of the present invention. The preparation method comprises the following steps: S11: providing a plastic-encapsulated product to be processed, the plastic-encapsulated product to be processed comprises a carrier, a plastic-encapsulated body is provided on the carrier, at least one electronic component is encapsulated in the plastic-encapsulated body, and the side of the electronic component close to the carrier has at least one pin; S12: half-cutting the plastic-encapsulated body in a first direction from the side away from the pin; S13: electroplating the plastic-encapsulated product to be processed to generate metal walls on both sides of the half-cut cut and a metal cover on the first surface of the plastic-encapsulated body; S14: filling the cut with a filler; S15: removing the carrier, and processing the second surface of the plastic-encapsulated body to expose the top of the pin to the plastic-encapsulated body; S16: fully cutting the plastic-encapsulated body in a second direction; and S17: removing the filler to obtain at least one three-sided metal-encapsulated packaging structure. The above steps are described in detail below in conjunction with the accompanying drawings and implementation methods.

[0015] Please also read Figure 1 and Figure 2 to Figure 9 ,in, Figure 2 to Figure 9 The present invention is a process flow chart of an embodiment of a method for preparing a packaging structure with metal encapsulation on three sides.

[0016] Regarding step S11: providing a plastic-encapsulated product to be processed, the plastic-encapsulated product to be processed includes a carrier, a plastic-encapsulated body is provided on the carrier, at least one electronic component is plastic-encapsulated in the plastic-encapsulated body, and the electronic component has at least one pin on a side close to the carrier, please refer to Figure 1 as well as Figure 2 ,in Figure 2A cross-sectional view of a plastic-encapsulated product to be processed provided in the present embodiment. In the present embodiment, the plastic-encapsulated product to be processed includes a carrier 21, on which a plastic-encapsulated body 22 is provided, and four electronic components 222 are plastic-encapsulated in the plastic-encapsulated body 22 (two of the electronic components are schematically shown in the figure, and the other two electronic components are blocked by the two electronic components shown in this viewing angle); the electronic components 222 can be chips or other devices, such as inductors, capacitors, resistors, etc. The front side (the side close to the carrier 21) of each of the electronic components 222 has six external pins 223 (out lead) (two of the external pins are schematically shown in the figure, and the remaining external pins are blocked by the two external pins shown in this viewing angle), and the external pins 223 are made of copper material, but the present invention is not limited to this.

[0017] The plastic-encapsulated product to be processed may be a product that has been subjected to patch redistribution layer (RDL) technology, external lead (Out Lead) electroplating and plastic encapsulation. The plastic encapsulation body 22 may be a structure known in the art.

[0018] In this embodiment, in order to clearly illustrate the technical solution of the present invention, four electronic components 222 are arranged in the plastic package body 22. In other embodiments, one, two or more electronic components 222 may be plastic-encapsulated in the plastic package body 22. Each of the electronic components 222 has one or more external pins 223 or general pins. The present invention does not limit the number of electronic components in the plastic package body 22 and the number and shape of pins on the electronic components.

[0019] Regarding step S12: half-cutting the plastic package body in a first direction from a side away from the pin, please refer to Figure 1 as well as Figure 3A-3B ,in Figure 3A A cross-sectional view of a half-cut plastic package body provided in this embodiment, Figure 3B for Figure 3A The corresponding top view. Figure 3B The first direction of cutting by the first cutting knife 31 is shown as the longitudinal direction, and the cutting line is located between two electronic components 222 adjacent to each other in the transverse direction. In other embodiments, the first direction of cutting by the first cutting knife 31 may also be the transverse direction (shown by the dotted line in the figure). Because the electronic components 222 and the external pins 223 are encapsulated in the encapsulation body 22 by the encapsulation material (such as resin), they are not visible in a top view, and are therefore indicated by dotted lines.

[0020] In a further embodiment, the thickness of the first cutting knife 31 for half-cutting the plastic package body 22 is adapted to the distance between two laterally adjacent electronic components 222, so that the plastic package body 22 can be cut and formed in one step.

[0021] In a further embodiment, a first cutting knife 31 can be used to half-cut the plastic package body 22 in a first direction along the outer side of the outer pin 223, and the depth of the cutting knife is between the top of the outer pin 223 and the carrier 21. The thickness and number of the cutting knife used for half-cutting can be adjusted according to needs, and the present invention does not make special restrictions. After the half-cutting operation, a half-cut incision is formed between two laterally adjacent electronic components 222 and on the outer side of the electronic component 222, so as to facilitate the subsequent electroplating operation. The bottom of the half-cut incision is located between the top of the outer pin 223 and the carrier 21, and the half-cut depth extends from the top of the outer pin 223 to the carrier 21. In the subsequent process of removing the carrier 21 and exposing the top of the outer pin 223, the electroplated metal at the bottom of the incision is also removed.

[0022] Preferably, the preparation method further comprises: performing surface conductive treatment on the plastic-encapsulated product to be processed, and forming a conductive film on both sides of the half-cut cut and the first surface of the plastic-encapsulated body. For this step, please refer to Figure 4 , a cross-sectional view of the plastic-sealed product to be processed after surface conductive treatment provided in this embodiment. The plastic-sealed product to be processed after half-cutting is subjected to surface conductive treatment, and a conductive film 41 is formed on both sides of the half-cut cut and the first surface of the plastic-sealed body 22, so that both sides of the half-cut cut and the first surface of the plastic-sealed body 22 are conductive, and are conducive to the subsequent electroplating operation. The surface conductive treatment can be carried out by adopting a treatment method of plasma roughening, glass etching, and copper plating, or by adopting a treatment method of sputtering copper, tin or nickel-gold alloy to form a conductive film 41 on both sides of the half-cut cut and the first surface of the plastic-sealed body 22. Plasma roughening, glass etching, and copper plating processes can be processes known in the art, and the tools and materials used can be adjusted according to requirements, and the present invention does not make special restrictions. The sputtering process can be a process known in the art, and the tools and materials used can be adjusted according to requirements, and the present invention does not make special restrictions.

[0023] Regarding step S13: electroplating the plastic-encapsulated product to be processed to form metal walls on both sides of the half-cut cut and to form a metal cover on the first surface of the plastic-encapsulated body, please refer to Figure 1 as well as Figure 5A-5B ,in Figure 5A This is a cross-sectional view of the plastic-encapsulated product to be processed after electroplating provided in this embodiment. Figure 5B for Figure 5ACorresponding top view. Among them, the first surface of the plastic package body 22 is a side surface away from the external pin 223. The metal walls 51 respectively generated on both sides of the half-cut incision, and the metal cover 52 generated on the first surface of the plastic package body 22, can enable the subsequently manufactured packaging structure to achieve multi-directional shielding and unidirectional transmission of internal signals, and improve the heat dissipation of the packaging structure and the air tightness of the packaging, thereby improving product performance. The metal used for electroplating can be copper or nickel-gold alloy. The electroplating process can be a process known in the art, and the tools and materials used can be adjusted according to needs, and the present invention does not make special limitations.

[0024] In a further embodiment, through photolithography, exposure and development, the plastic package body 22 of the electronic component 222 on both sides in the same direction as the half-cutting direction is exposed to the metal cover 52 . Figure 5B The electronic component 222 and the external pin 223 are indicated by dotted lines. Since the electronic component 222 and the external pin 223 are encapsulated in the plastic body 22 by a plastic encapsulation material (such as resin), and the metal cover 52 is generated by electroplating on the first surface of the plastic body 22, the electronic component 222, the external pin 223 and the plastic body 22 are below the metal cover 52 when viewed from a top view; and the electronic component 222 is not covered by the metal cover 52 above the plastic body 22 on both sides of the Y direction.

[0025] Regarding step S14: filling the incision with a filler, please refer to Figure 1 as well as Figure 6 ,in Figure 6 The cross-sectional view of the cutout after filling provided in this embodiment. The cutout after electroplating is filled with filler 61, so that the electronic components 222 can be connected and supportive in the subsequent carrier 21 removal process, surface mechanical grinding process and cutting process to form a single package structure. The filler 61 is a soluble substance or a fusible substance, so as to be removed by dissolving or melting process in the subsequent process.

[0026] In a further embodiment, the filler 61 may be a hydrogel, a pyrolyzer or a photolyzer. Hydrogel is a cross-linked polymer in which a portion of hydrophobic groups and hydrophilic residues are introduced into a water-soluble polymer having a network cross-linked structure. The hydrophilic residues combine with water molecules to connect the water molecules inside the network, while the hydrophobic residues swell when exposed to water. It uses water as a dispersion medium, is soft in nature, can maintain a certain shape, and can absorb a large amount of water; the hydrogel can be removed by placing it in water and heating it. Pyrolyzer is a solvent-based adhesive that has a certain adhesive force at room temperature and can play a role in positioning and supporting; as long as the temperature is heated to the set temperature, the adhesive force will disappear, and simple peeling can be achieved, with less residue and no pollution to the adherend. Photolyzer has a certain adhesive force, which can play a role in positioning and supporting; after being exposed to light, a photodecomposition reaction will occur and it will become water-soluble, which can achieve simple peeling.

[0027] Regarding step S15: removing the carrier and processing the second surface of the plastic package to expose the top of the pin to the plastic package, please refer to Figure 1 as well as Figure 7 ,in Figure 7 The cross-sectional view after the carrier provided in the present embodiment is removed and the second surface of the plastic package body is processed. The second surface is opposite to the first surface. After removing the carrier 21, the second surface of the plastic package body 22 is processed so that the top of the external pin 223 is exposed to the plastic package body 22, and the exposed portion of the external pin 223 can be used as a contact surface when the subsequently formed packaging structure is fixedly connected to an external component. At the same time, the electroplated metal at the bottom of the half-cut is also removed to expose the internal filler 61.

[0028] In a further embodiment, the second surface of the plastic package body 22 may be subjected to a surface mechanical grinding process to grind and thin the second surface of the plastic package body 22, thereby exposing the top of the external pin 223 to the second surface of the plastic package body 22. That is, the upper surface of the copper external pin is exposed to the second surface of the plastic package body 22 to serve as a contact surface when the subsequently formed packaging structure is fixedly connected to an external component.

[0029] Regarding step S16: performing full cutting of the plastic package body in the second direction, please refer to Figure 1 as well as Figure 8 ,in Figure 8 The top view of the plastic package body being fully cut is provided in this embodiment. The thickness and number of the cutting blades used for full cutting can be adjusted according to the needs, and the present invention does not make any special restrictions. Figure 3B As shown in the figure, when the first direction is the longitudinal direction, the second direction is the transverse direction, and the cutting line is located between two electronic components 222 adjacent to each other in the longitudinal direction.

[0030] In a further embodiment, the thickness of the second cutting blade 81 for fully cutting the plastic package 22 is adapted to the distance between two longitudinally adjacent electronic components 222, so that the second cutting blade 81 can be the same thickness as or different from the first cutting blade 31.

[0031] In a further embodiment, a second cutting knife 81 may be used to fully cut the plastic package 22 in the second direction along the outer side of the outer pin 223. After the full cutting operation, the plastic package 22 between two longitudinally adjacent electronic components 222 is cut through to form a longitudinally independent plastic package (the space between two transversely adjacent electronic components 222 is filled with filler 61).

[0032] Regarding step S17: removing the filler to obtain at least one three-sided metal encapsulation packaging structure, please refer to Figure 1 as well as Fig. 9 ,in Fig. 9 This is a cross-sectional view of the plastic package body after the filler is removed provided in this embodiment.

[0033] For the plastic-encapsulated body 22 using hydrogel as filler, the plastic-encapsulated body 22 can be placed in water and heated to remove the filled hydrogel, thereby obtaining an independent product with a three-sided metal encapsulation structure. For the plastic-encapsulated body 22 using other fillers, the filler can be removed by a corresponding dissolving or melting process, for example, thermally degraded glue can be removed by heating, and photolyzed glue can be removed by irradiation.

[0034] Preferably, after step S17, the method further includes: performing surface anti-oxidation treatment on the metal cover, the metal wall and the top of the pin. Surface anti-oxidation treatment methods such as tin or nickel-gold alloy can be used to prevent the exposed metal surface in the three-sided metal encapsulation packaging structure from being oxidized, and at the same time, the external pins of the three-sided metal encapsulation packaging structure can be better tin-fused for SMT (Surface Mount Technology) when connected to external components.

[0035] The method for preparing a packaging structure with metal encapsulation on three sides of the present invention utilizes half-cutting, electroplating, full-cutting, anti-oxidation and other processes. The three sides of the formed packaging structure are electroplated with metal encapsulation, which can enable the packaging structure to achieve multi-directional shielding and unidirectional transmission of internal signals, and improve the heat dissipation of the packaging structure and the air tightness of the packaging, thereby improving product performance.

[0036] See also Figures 10A-10B, a three-dimensional diagram of an embodiment of a three-sided metal-encapsulated packaging structure of the present invention. The three-sided metal-encapsulated packaging structure 100 of the present invention comprises: a plastic encapsulation body 101 and at least one electronic component encapsulated in the plastic encapsulation body 101 (internal structure, not shown in the figure). The first surface of the plastic encapsulation body 101 is covered with a metal cover 103, and the opposite two sides of the plastic encapsulation body 101 are covered with metal walls 104. The side of the electronic component away from the metal cover 103 has at least one pin 102, and the top of the pin 102 is exposed to the second surface of the plastic encapsulation body 101; wherein the second surface is opposite to the first surface.

[0037] In a further embodiment, the metal cover 103 and the metal wall 104 are prepared by half-cutting the plastic package 101 from the side away from the pin 102 and then electroplating. The metal cover 103 and the metal wall 104 can be made of copper or nickel-gold alloy.

[0038] In a further embodiment, a conductive film (not shown) is provided between the first surface of the plastic package 101 and the metal cover 103, and a conductive film is provided between the two opposite side surfaces of the plastic package 101 and the metal wall 104. That is, the first surface and the two opposite side surfaces of the plastic package are subjected to a conductive treatment before the metal cover and the metal wall are formed by electroplating.

[0039] In a further embodiment, the metal cover 103, the metal wall 104 and the top of the pin 102 are subjected to surface anti-oxidation treatment. A surface anti-oxidation treatment method such as tin or nickel-gold alloy can be used to prevent the exposed metal surface of the three-sided metal encapsulation packaging structure 100 from being oxidized, and at the same time, the pin 102 of the three-sided metal encapsulation packaging structure 100 can be better SMT tin fused when connected to an external component.

[0040] In this embodiment, in order to clearly illustrate the technical solution of the present invention, the electronic component has 6 pins 102. The pins 102 are the outer pins (out lead) of the electronic component, which are used to connect to an external component (not shown in the figure), and the pins 102 are made of copper. In other embodiments, the electronic component may have one, two or more pins 102, and the pins 102 may be the outer pins (out lead) or general pins (pin) of the electronic component. The present invention does not limit the number, material and shape of the pins on the electronic component.

[0041] The three-sided metal encapsulation packaging structure of the present invention is electroplated on three sides of the metal encapsulation, which can enable the packaging structure to achieve multi-directional shielding and unidirectional transmission of internal signals, and improve the heat dissipation of the packaging structure and the air tightness of the packaging, thereby improving product performance.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a three-sided metal encapsulation packaging structure, characterized in that: The steps include: (1) providing a plastic-encapsulated product to be processed, the plastic-encapsulated product to be processed comprising a carrier, a plastic-encapsulated body being provided on the carrier, at least one electronic component being plastic-encapsulated in the plastic-encapsulated body, and at least one pin being provided on a side of the electronic component close to the carrier; (2) half-cutting the plastic package body in a first direction from a side away from the pin; (3) electroplating the plastic-encapsulated product to be processed to form metal walls on both sides of the half-cut, and to form a metal cover on the first surface of the plastic-encapsulated body, wherein the first surface of the plastic-encapsulated body is a side surface away from the pins; (4) filling the incision with a filler; (5) removing the carrier and processing the second surface of the plastic package body to expose the top of the pin to the plastic package body, the second surface being opposite to the first surface; (6) performing full cutting of the plastic package body in a second direction, wherein the second direction is perpendicular to the first direction; (7) removing the filler to obtain at least one three-sided metal encapsulation packaging structure; Wherein, step (2) further comprises: half-cutting the plastic package body in a first direction along the outer side of the pin, cutting to a depth between the top of the pin and the carrier; Step (5) further includes: performing a surface mechanical grinding process on the second surface of the plastic package body to expose the top end of the pin to the plastic package body.

2. The preparation method according to claim 1, characterized in that: Before step (3), the method further includes: performing surface conductive treatment on the plastic-encapsulated product to be processed, and forming a conductive film on both side surfaces of the half-cut and the first surface of the plastic-encapsulated body.

3. The preparation method according to claim 2, characterized in that: The surface conductive treatment further adopts a treatment method of plasma roughening, glass etching, copper plating; or a treatment method of sputtering copper, tin or nickel-gold alloy.

4. The preparation method according to claim 1, characterized in that: The filler used in step (4) is hydrogel, thermal gel or photo gel.

5. The preparation method according to claim 1, characterized in that: After step (7), the method further includes: performing surface anti-oxidation treatment on the metal cover, the metal wall and the top of the pin.

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