Chip packaging method and device assembly
By defining pin bases and connecting ribs on a metal substrate roll, performing injection molding and electroplating, and combining heat sink and capping bonding, the problems of low efficiency and high cost in ACS packaging technology are solved, enabling efficient mass production and performance-optimized device packaging.
Patent Information
- Application Number
- CN202511067240.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-21
AI Technical Summary
Existing ACS packaging technology suffers from low processing efficiency and high cost, mainly because copper coils need to be processed individually and require polishing and surface treatment, which affects device performance and material costs.
The pin base and connecting ribs are defined on the metal substrate roll by patterning, and the device frame is formed by injection molding. Conductive metal is electroplated on the substrate roll, and combined with heat sink and capping bonding, to achieve mass production of multiple devices.
By mass-producing multiple devices, production efficiency has been significantly improved, material and processing costs have been reduced, and the electrical performance and hermeticity of the devices have been improved.
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Figure CN120998780A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to chip packaging technology, in particular to a chip packaging method and device assembly. BACKGROUND
[0002] ACS / ACC packaging is a packaging technology that uses substrate and outer frame cavity to form a cavity, fixes the chip and other elements by welding or adhesive, connects the chip with the pins on the outer frame through wire bonding, and finally seals with high-performance sealing material to ensure the sealing of the cavity and prevent air and moisture from entering.
[0003] The mainstream processing flow of the commonly used ACS packaging is: copper roll → punching → surface treatment → polishing → injection molding → electroplating. In order to ensure the air tightness and appearance quality of the lead frame, the copper roll needs to be cut into single or single strip first, and then surface treatment and polishing are performed. It is equivalent to manufacturing devices one by one, resulting in low processing efficiency.
[0004] Another processing flow of ACS packaging is: copper roll → punching → annealing → polishing → electroplating. Although this scheme cancels the surface treatment process, in order to ensure the appearance quality of the product, the copper roll still needs to be cut into single first and then polished, resulting in low processing efficiency and high cost. In addition, this scheme needs to be slotted on the structure plane or the inner side, resulting in too long wire bonding between the chip and the pin, which affects the performance of the device. SUMMARY
[0005] In order to solve one of the above technical defects, a chip packaging method and device assembly are provided in the embodiments of the present application.
[0006] According to a first aspect of the embodiments of the present application, a chip packaging method is provided, comprising:
[0007] The first metal substrate roll is subjected to a patterning process to define a plurality of device pin bases and connecting ribs connecting the plurality of device pin bases on the first metal substrate roll;
[0008] The first metal substrate roll is subjected to injection molding to form a device frame around each device pin base;
[0009] The first conductive metal is electroplated on the pin base of each device on the first metal substrate roll, and the part located inside the device frame forms an inner pin, and the part located outside the device frame forms an outer pin;
[0010] A heat sink corresponding to each device and a connecting rib connecting the heat sinks are formed on the second metal substrate roll;
[0011] The second metal substrate roll is aligned with the first metal substrate roll, and the device frame is bonded to the heat sink;
[0012] fixing each chip on the inner surface of the corresponding heat sink, and wire-bonding the chip to the inner pin of the corresponding device;
[0013] adhering the cover to the device frame of each device;
[0014] removing the connecting rib on the first metal substrate roll and the second metal substrate roll to obtain a plurality of devices.
[0015] According to a second aspect of the embodiments of the present application, a device assembly is provided, which is obtained by using any of the packaging methods described above.
[0016] The technical solutions provided by the embodiments of the present application perform patterning on the first metal substrate roll to define a plurality of device pin bases and connecting ribs connecting the plurality of device pin bases on the first metal substrate roll; perform injection molding on the first metal substrate roll to form a device frame around each of the plurality of device pin bases; electroplate a first conductive metal on each of the device pin bases on the first metal substrate roll, and form inner pins on the part inside the device frame and form outer pins on the part outside the device frame; form a heat sink corresponding to each device and connecting ribs connecting the heat sinks on the second metal substrate roll; align the second metal substrate roll with the first metal substrate roll, and adhere the device frame to the heat sink; fix each chip on the inner surface of the corresponding heat sink, and wire-bond the chip to the inner pin of the corresponding device; adhere the cover to the device frame of each device; and remove the connecting rib on the first metal substrate roll and the second metal substrate roll to obtain a plurality of devices, which realizes batch production of a plurality of devices and can greatly improve the production efficiency. BRIEF DESCRIPTION OF DRAWINGS
[0017] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and illustrate the illustrative embodiments of the present application and their description serve to explain the present application, but do not constitute improper limitations on the present application. In the drawings:
[0018] Figure 1 a flowchart of the chip packaging method provided by the embodiments of the present application;
[0019] Figure 2 a sectional view of a single device obtained by the chip packaging method provided by the embodiments of the present application;
[0020] Figure 3 a structural schematic diagram of the plurality of devices formed on the metal substrate roll in the chip packaging method provided by the embodiments of the present application.
[0021] Reference Signs:
[0022] 1-device frame; 2-inner pin; 3-outer pin; 4-heat sink; 5-chip; 6-cover; 7-connection rib; 71-longitudinal rib; 72-transverse rib; 8-device; 9-wire; 10-first adhesive; 11-second adhesive; 12-third adhesive; 13-solder. DETAILED DESCRIPTION
[0023] In order to make the technical solutions and advantages in the embodiments of the present application more clear, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0024] The reason why the traditional packaging scheme needs to be plated with gold is the following three points. First, the copper of the main structure is easy to oxidize and corrode, and needs to be protected by plating gold. Second, only gold can meet the interface bonding requirements of WB wire, die attach solder and PCB board. More importantly, single devices with exposed pins can only be processed using a hanging plating method. The main cost of this electroplating method is the operation and labor cost, so the cost of one-time gold plating is much lower than that of multiple electroplating. Therefore, how to efficiently electroplate is an important prerequisite for canceling gold plating.
[0025] The fundamental reason why the current ACS device is inefficient is twofold. First, in order to ensure the appearance quality of the heat sink, the copper material needs to be polished. Then, the frame and the heat sink need to be surface treated to improve the air tightness of the product. This surface treatment and polishing method can only be processed single by single, resulting in extremely low processing efficiency of ACS packaging and materials.
[0026] The above reasons lead to the current ACS packaging being a single full-gold product in structure. Because gold is used for plating, not only does it make the material cost too high, but also the efficiency of single processing is extremely low. This leads to high costs of such packaging.
[0027] The embodiment provides a chip packaging method, which is suitable for packaging chips and can greatly improve production efficiency.
[0028] As shown in Figures 1 to 3 the chip packaging method comprises the following steps.
[0029] Step 101, performing a patterning treatment on a first metal base material roll to define a plurality of device pin bases and connection ribs connecting the plurality of device pin bases on the first metal base material roll.
[0030] The first metal substrate roll can adopt a material with certain strength and good thermal conductivity, such as oxygen-free copper C10100, C1011, TU0, or copper alloy C19210, C19400, C18400. Taking copper as an example, the copper is made into a sheet and wound into a roll as a copper roll.
[0031] The first metal substrate roll is subjected to a patterning process, which can be etching or punching by mechanical or chemical means, to remove part of the copper and leave the pin bases of the plurality of devices and the connecting ribs 7, which are used to connect the pin bases of the plurality of devices, so that the plurality of devices are temporarily connected together, and a plurality of devices can be mass-produced on one first metal substrate roll.
[0032] Step 102, the first metal substrate roll is subjected to an injection molding process to form a device frame around each pin base of the plurality of devices.
[0033] A mold is prepared in advance, and the first metal substrate roll after the patterning process is placed in the mold for injection molding, and a device frame 1 is formed around each pin base of the plurality of devices after solidification. The device frame 1 is a cylindrical structure with a rectangular shape. Part of the pin base in the above step is located inside the device frame 1, and the other part is located outside the device frame 1.
[0034] Step 103, electroplating a conductive metal on the pin bases of the plurality of devices on the first metal substrate roll, the part inside the device frame forms an inner pin, and the part outside the device frame forms an outer pin.
[0035] A first conductive metal is electroplated on the pin bases of the plurality of devices on the first metal substrate roll. The first conductive metal can be a metal that can be electroplated on the surface of copper and has good conductivity and heat dissipation capacity, such as one or more of silver, titanium, nickel, palladium, gold, and aluminum. The thickness of the first conductive metal is 0.01-20 μm. Specifically, the surface of the part of the pin base inside the device frame 1 is electroplated with silver as an inner pin 2 of the device, and the surface of the part of the pin base outside the device frame 1 is electroplated with silver as an outer pin 3 of the device.
[0036] Step 104, forming a heat sink corresponding to each device and a connecting rib connecting the heat sinks on the second metal substrate roll.
[0037] The second metal substrate roll can adopt a material with certain strength and good thermal conductivity, such as one or more of copper with different oxygen contents, copper-molybdenum-copper with different proportions, diamond copper, diamond aluminum, and copper-based carbon composite materials. Taking copper as an example, the copper is made into a sheet and wound into a roll as a copper roll.
[0038] The heat sink 4 corresponding to each device is formed on the second metal substrate roll. The second metal substrate roll can be patterned according to the shape of the heat sink 4, for example, etched or grooved by mechanical or chemical means, to form the heat sink 4 and the connecting rib 7. The connecting rib 7 connects each heat sink 4 together to realize batch production.
[0039] The steps 101 to 104 above belong to the material process, which is divided into two production lines of the frame and the heat sink. The following steps belong to the packaging process, which is used to complete the device packaging.
[0040] In step 105, the second metal substrate roll is aligned with the first metal substrate roll, and the device frame is bonded to the corresponding heat sink.
[0041] In step 105, the second metal substrate roll is aligned with the first metal substrate roll, and the device frame is bonded to the corresponding heat sink.
[0042] In step 106, each chip is fixed to the inner surface of the corresponding heat sink, and the chip is wire-connected to the inner pin of the corresponding device.
[0043] In step 106, each chip 5 is fixed to the inner surface of the corresponding heat sink 4, which can be bonded by thermal conductive glue. Alternatively, it can also be welded by solder 13, which can be one or more of the following: nano-silver glue, nano-copper glue, gold-tin solder, tin paste, conductive glue, epoxy resin, and silicone resin. In this way, the heat generated by the chip 5 during operation can be quickly conducted to the heat sink 4 through the solder 13, and quickly dissipated through the heat sink 4.
[0044] Then, the chip pin and the inner pin 2 are connected together by wire 9 using the wire bonding method. The wire 9 is a wire material such as solder wire, silver wire, aluminum wire, copper wire, aluminum-clad copper wire, palladium-copper wire, and aluminum-magnesium wire.
[0045] In step 107, the cover is bonded to the device frame of each device.
[0046] The size of the cover 6 matches the size of the device frame 1. The cover 6 is connected to the top of the device frame 1, which closes the top opening of the device frame 1, so that the chip 5 is located in a closed space.
[0047] In step 108, the connecting rib on the first metal substrate roll and the second metal substrate roll is removed to obtain a plurality of devices.
[0048] After batch production of multiple devices, the connecting rib 7 on the first metal substrate roll and the second metal substrate roll is cut off to obtain multiple single devices 8, and the packaging process is completed.
[0049] The technical scheme provided by the embodiment is characterized in that the first metal substrate roll is subjected to a patterning process to define a plurality of device pin bases and connecting ribs connecting the plurality of device pin bases on the first metal substrate roll; the first metal substrate roll is subjected to an injection molding process to form a device frame around each of the plurality of device pin bases; a first electrically conductive metal is electroplated on each of the device pin bases on the first metal substrate roll, a part of the first electrically conductive metal inside the device frame forms an inner pin, and a part of the first electrically conductive metal outside the device frame forms an outer pin; a heat sink corresponding to each device and connecting ribs connecting the heat sinks are formed on a second metal substrate roll; the second metal substrate roll is aligned with the first metal substrate roll, and the device frame is bonded to the heat sink; each chip is fixed to an inner surface of the corresponding heat sink, and the chip is wire-bonded to the inner pin of the corresponding device; a cover is bonded to the device frame of each device; and the connecting ribs on the first metal substrate roll and the second metal substrate roll are removed, thereby obtaining a plurality of devices, achieving batch production of the plurality of devices, and doubling the production efficiency.
[0050] On the basis of the above technical scheme, in step 104, the heat sink corresponding to each device and the connecting ribs connecting the heat sinks are formed on the second metal substrate roll, specifically, the second metal substrate roll is subjected to stamping to form a stepped sink on the outer edge of each region to be formed into a heat sink, and the size of the sink is matched with the lower part of the device frame 1. The obtained sink 4 is a structure in which the middle part is protruding and the periphery is recessed to form a sink.
[0051] In step 105, the second metal substrate roll is aligned with the first metal substrate roll, and the device frame is bonded to the heat sink, including: first, aligning the second metal substrate roll with the first metal substrate roll, and then embedding the bottom of each device frame 1 in the first metal substrate roll into the sink of the heat sink 4 in the second metal substrate roll. Then, glue is applied between the surfaces of the device frame 1 and the heat sink 4 in contact to bond the device frame 1 and the heat sink 4 together.
[0052] Specifically, the first adhesive 10 is injected between the bottom surface and the side surface of the device frame 1 and the heat sink to bond the bottom surface and the side surface of the device frame 1 to the heat sink 4, thereby improving the connection firmness.
[0053] After the second metal substrate roll is subjected to stamping to form a sink in the above scheme, silver is electroplated on the surface of the second metal substrate roll, which facilitates the subsequent fixation of the chip on the surface of the heat sink 4.
[0054] Further, before the connecting ribs are removed, the surfaces of the device frame 1, the heat sink 4 and the outer pins 3 are electroplated with a second conductive metal to improve the solderability of the device. The second conductive metal can be one or more of gold, silver, nickel, palladium, tin or a stack thereof, and the thickness of the second conductive metal is 0.01 μm to 50 μm. For example, the second conductive metal can be pure tin, dull tin, bright tin, tin-lead alloy or lead-free tin, and the thickness of the tin layer is 5 μm to 50 μm.
[0055] In addition, after the pins of the chip 5 are connected to the inner pins 2 by the solder wires 9, the surfaces of the inner pins 2 are coated with a second adhesive 11 to further fix and seal the connection.
[0056] The cover 6 is adhered to the top of the device frame 1 by a third adhesive 12. In combination with the way the heat sink 4 is adhered to the device frame 1, the sealing effect of the device is further improved, and the entry of water vapor into the device is avoided.
[0057] As shown in Figure 3 On the basis of the above technical solution, in the step 101, the first metal substrate roll is subjected to a patterning process to define the pin bases of the plurality of devices and the connecting ribs connecting the pin bases of the plurality of devices on the first metal substrate roll. Specifically, the first metal substrate roll is subjected to a patterning process to define the pin bases of the plurality of devices and the connecting ribs on the first metal substrate roll. The pin bases of the plurality of devices are arranged in at least two columns along the width direction of the first metal substrate roll, and the pin bases of the plurality of devices in each column are arranged in sequence along the length direction of the first metal substrate roll. The spacing between the columns is less than twice the width of the device and greater than 0.5 times the width of the device.
[0058] One embodiment is as shown in Figure 3 The connecting ribs 7 include longitudinal ribs 71 and transverse ribs 72. The longitudinal ribs 71 extend along the length direction of the first metal substrate roll, and the transverse ribs 72 extend along the width direction of the first metal substrate roll and are located between two longitudinal ribs 71. The longitudinal ribs 71 and the transverse ribs 72 divide a plurality of device spaces. The pin bases are located in the device spaces, and the pin bases are connected to the transverse ribs 72 on both sides thereof, respectively.
[0059] Figure 3 In one embodiment, three longitudinal ribs 71 are arranged in parallel, and one device space accommodates one device 8. The outer pins of the device are connected to the longitudinal ribs 71. After the device is packaged, the longitudinal ribs 71 and the transverse ribs 72 are all cut off to obtain a single device.
[0060] Alternatively, two longitudinal ribs 71 and a plurality of transverse ribs 72 can also be used, and one device space accommodates two devices 8.
[0061] After the step 103, the first metal substrate roll can be cut to obtain a roll with a preset length, facilitating production.
[0062] The first adhesive 10, the second adhesive 11 and the third adhesive 12 can be one or a mixture of epoxy glue, acrylic glue, polyurethane glue, silver-based filler metal and copper-based filler metal.
[0063] Based on the above technical solution, the embodiment further provides a device assembly made by the packaging method provided in any of the above.
[0064] As shown in the above technical solution, the embodiment further provides a device assembly, which comprises a device frame 1, a heat sink 4, pins and a cover 6. Figure 2
[0065] The device frame 1 comprises a main body part and a support part, the support part is located on the upper surface of the main body part, and the cross-sectional area of the support part is smaller than that of the main body part, so as to form a pin surface on the surface of the main body part beside the support part.
[0066] The edge of the upper surface of the heat sink 4 is recessed downward to form a sink, and the bottom of the device frame 1 is embedded in the sink and fixed by the first adhesive 10. The middle part of the upper surface of the heat sink 4 is used to fix the chip 5.
[0067] The pins are arranged on the pin surface of the device frame 1, and the part of the pins in the device frame 1 is used as an inner pin 2, and the part of the pins outside the device frame 1 is used as an outer pin 3. The chip 5 is connected to the inner pin 2 by a bonding wire 9, and the second adhesive 11 is arranged on the surface of the inner pin 2 and the bonding wire 9.
[0068] The cover 6 is fixed on the top end of the support part of the device frame 1 and can be bonded by the third adhesive 12.
[0069] The middle part of the heat sink 4 forms a boss structure, and the periphery is a sink. The protruding height of the boss is greater than the thickness of the first adhesive 1 and smaller than the height of the inner cavity of the device. Preferably, the top of the chip 5 is flush with the height of the bonding wire of the device frame 1. The calculation method is: inner pin height + first adhesive thickness - chip thickness - chip solder thickness.
[0070] The device frame 1 can be epoxy resin, PPS, LCP or ceramic such as aluminum oxide and aluminum nitride.
[0071] The chip 5 is a substrate chip of LDMOS, GaN, Si, SiC, etc. The solder used for fixing the chip 5 on the surface of the heat sink 4 is one or a mixture of nano-silver glue, nano-copper glue, gold-tin solder, tin paste, conductive glue, epoxy resin and silicone resin.
[0072] The cover 6 can be a metal cover, a plastic cover or a ceramic cover.
[0073] In the above scheme, silver plating is only applied to the place where the inner pin and the chip are connected, which can greatly reduce the material cost. Using coil or strip processing can significantly improve the production efficiency. Tinning the outer surface of the device frame, heat sink and outer pin can cover the poor appearance of the device, thereby canceling the polishing process of the frame and heat sink and realizing coil processing.
[0074] In addition, the heat sink is arranged in a stepped structure, which can reduce the 3D length of the solder wire, thereby reducing the parasitic inductance and improving the electrical performance, and can also improve the air tightness of the product. The glue coating area between the stepped structure and the device frame is also increased, which can also improve the air tightness of the product.
[0075] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.
[0076] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.
[0077] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0078] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0079] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the application can be practiced otherwise than as specifically described herein.
Claims
1. A chip packaging method, characterized in that, include: The first metal substrate roll is patterned to define the pin bases of multiple devices and the connecting ribs connecting the pin bases of multiple devices on the first metal substrate roll. The first metal substrate roll is injection molded to form device frames around the pin substrates of multiple devices. A first conductive metal is electroplated on the lead substrate of each device on the first metal substrate roll, with the portion located inside the device frame forming an inner lead and the portion located outside the device frame forming an outer lead. Heat sinks corresponding to each device and connecting ribs connecting the heat sinks are formed on the second metal substrate roll. Align the second metal substrate roll with the first metal substrate roll, and then bond the device frame to the heat sink accordingly. Each chip is fixed to the inner surface of the corresponding heat sink, and the chips are wire-bonded to the inner pins of the corresponding device. Adhere the caps to the corresponding device frames of each component; The connecting ribs on the first and second metal substrate rolls are removed to obtain multiple devices.
2. The chip packaging method according to claim 1, characterized in that, Forming heat sinks corresponding to each device on the second metal substrate roll includes: The second metal substrate roll is stamped to form a stepped platform at the outer edge of each heat sink area to be formed, and the size of the platform matches the lower part of the device frame.
3. The chip packaging method according to claim 2, characterized in that, Align the second metal substrate roll with the first metal substrate roll, and bond the device frame to the heat sink accordingly, including: Align the second metal substrate roll with the first metal substrate roll; The bottom of each device frame in the first metal substrate roll is embedded into the heat sink platform in the second metal substrate roll. Adhesive is applied between the surfaces of each device frame that come into contact with the heat sink to bond the device frame and the heat sink together.
4. The chip packaging method according to claim 2, characterized in that, The first metal substrate roll is patterned to define pin bases of multiple devices and connecting ribs connecting the pin bases of the multiple devices on the first metal substrate roll, specifically: The first metal substrate roll is patterned to define the pin bases and connecting ribs of multiple devices on the first metal substrate roll. The pin bases of the multiple devices are arranged in at least two columns along the width direction of the first metal substrate roll, and the pin bases of the multiple devices in each column are arranged sequentially along the length direction of the first metal substrate roll.
5. The chip packaging method according to claim 4, characterized in that, The connecting ribs include longitudinal ribs and transverse ribs. The longitudinal ribs extend along the length direction of the first metal substrate roll, and the transverse ribs extend along the width direction of the first metal substrate roll and are located between the two longitudinal ribs. The longitudinal ribs and transverse ribs divide multiple device spaces. The pin base is located in the device space, and the pin base is connected to the transverse ribs on both sides of it.
6. The chip packaging method according to claim 1, characterized in that, Also includes: Before removing the connecting ribs, the process also includes: A second conductive metal is electroplated on the surface of the device frame, heat sink, and external leads. The second conductive metal is one or more of gold, silver, nickel, palladium, and tin in a stack.
7. The chip packaging method according to claim 1, characterized in that, A first conductive metal is electroplated on the lead substrate of each device on the first metal substrate roll, specifically, one or more layers of silver, titanium, nickel, palladium, gold, and aluminum are electroplated on the lead substrate of each device on the first metal substrate roll.
8. The chip packaging method according to claim 1, characterized in that, The first metal substrate roll is a copper roll; the second metal substrate roll is a copper roll.
9. The chip packaging method according to claim 1, characterized in that, Before forming heat sinks corresponding to each device on the second metal substrate roll, the process also includes: electroplating silver on the surface of the second metal substrate roll.
10. A device assembly, characterized in that, It is obtained by using any one of the encapsulation methods of claims 1-9.