Bare copper carrier thermal ultrasonic bonding and chip packaging method and chip

Abstract

The invention belongs to the field of semiconductor integrated circuit packaging, and discloses a bare copper carrier thermal ultrasonic bonding and chip packaging method and a chip, an oxide layer of a bare copper carrier bonding area is ground and broken through a chopper to form a clean grinding bonding area, chip / pin interconnection is achieved through direct thermal ultrasonic bonding in the grinding bonding area, then silver glue is dispensed to wrap welding spots, then curing is conducted, and the chip / pin is packaged. And finally, chip-pin bonding is completed. The oxidation layer is physically broken through grinding, so that the problem of bare copper bonding oxidation is fundamentally solved, and a traditional plating process is omitted; silver colloid wrapping not only can isolate secondary oxidation of the welding spots, but also enhances the bonding interface of the molding compound, and secondary bonding after curing ensures that the silver colloid does not interfere with lead bonding. A precious metal coating and an anti-oxidation gas protection system are thoroughly eliminated, and the frame material and equipment modification cost is greatly reduced; the bonding reliability is guaranteed through oxide layer breaking, the welding spot oxidation resistance and the packaging structure binding force are synchronously improved through elargol wrapping, and the dual purposes of high-reliability packaging and remarkable cost reduction are achieved on a bare copper carrier as a whole.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor integrated circuit packaging and testing, and in particular relates to a bare copper carrier thermosonic bonding and chip packaging method. Background Art

[0002] In the field of integrated circuit packaging, thermosonic bonding is the most common interconnection technology. It has become one of the key technologies for achieving electrical signal connections between chips and frame carriers, frame pins, and between frame carriers and frame pins through bonding metal wires. Because thermosonic bonding is sensitive to oxidation, the copper frame bonding area usually needs to be plated with a thin oxidation-resistant metal layer such as silver, nickel-palladium-gold, etc. to ensure good interconnection between the bonding metal wires and the plating layer. For frame carriers that require ground wires, the thermosonic bonding process has two conditions: with or without a thin oxidation-resistant metal layer. In the existing technology, although the frame carrier coated with an oxidation-resistant thin metal layer can meet the oxidation requirements of thermal ultrasonic bonding, the bonding strength between the oxidized thin metal and the plastic packaging material is poor, which affects the packaging reliability, and the nickel-palladium-gold plating significantly increases the frame cost; while the frame carrier not coated with an oxidation-resistant thin metal layer can avoid plating-related problems, it requires the ultrasonic bonding machine bonding area to be sealed and continuously injected with anti-oxidation-reduction gas, which undoubtedly increases the packaging cost. It can be seen that how to effectively reduce the packaging cost of the frame carrier while ensuring the reliability of thermosonic bonding has become an urgent problem to be solved in the current thermosonic bonding and chip packaging technology. Summary of the Invention

[0003] The purpose of the present invention is to provide a bare copper carrier thermosonic bonding and chip packaging method. The method realizes thermosonic bonding and chip packaging under the condition of bare copper carrier oxidation, thereby reducing the cost of equipment modification of the existing bare copper carrier thermosonic bonding and chip packaging method.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A bare copper carrier thermosonic bonding and chip packaging method, comprising: The oxide layer of the bare copper carrier bonding area of ​​the frame is broken by a wedge grinding bonding method, so that a grinding bonding area is formed on the bare copper carrier bonding area; the chip is bonded to the frame; In the grinding bonding area of ​​the bare copper carrier, the bare copper carrier is bonded and interconnected with the chip and the frame pins respectively by using a thermosonic bonding method; The bare copper carrier ultrasonic bonding solder joints are wrapped by dispensing silver glue; After the silver glue is cured, the chip and the frame pins are bonded and interconnected using thermosonic bonding.

[0005] Furthermore, before removing the oxide layer of the bare copper carrier bonding area of ​​the frame by using a wedge grinding bonding method, the method includes: The frame with the chip attached is placed in the bonding area of ​​the thermosonic bonding machine.

[0006] Furthermore, the method of using a wedge grinding bonding method to break the oxide layer of the bare copper carrier bonding area of ​​the frame includes: A splitter was used to grind and bond the oxide layer in the bonding area of ​​the bare copper carrier to form a grinding bonding area of ​​the bare copper carrier. The temperature of the bonding area of ​​the ultrasonic bonding machine was 100-120 °C, the splitter bonding pressure was 60-80 g, the splitter bonding power was 120-140 mA, the splitter grinding amplitude was 6-8 um, and the grinding cycle was 5-8 times.

[0007] Furthermore, the bare copper carrier is bonded to the chip and the frame pins respectively by using a thermosonic bonding method in the grinding bonding area of ​​the bare copper carrier, including: Bonding a first solder joint in the ground bonding area of ​​the bare copper carrier using thermosonic bonding; On the chip or the frame pin, a second solder joint is bonded by using a thermosonic bonding method to achieve bonding interconnection between the bare copper carrier and the chip and the frame pin respectively.

[0008] Furthermore, the process of bonding the first solder joint in the ground bonding area of ​​the bare copper carrier by thermosonic bonding includes: The bonding method of the first solder joint is set using a five-stage parameter setting method, as follows: For the solder ball forming process of the first solder joint, set the parameters of the first to third stages, including: The bonding ultrasonic power is 80~120 mA; the bonding pressure is 7~12 g; the grinding bonding amplitude is 2~3 um; For the intermetallic compound growth process of the first solder joint, set the fourth section parameters, including: The bonding ultrasonic power is 100~200 mA; the bonding pressure is 10~14 g; For the bonding completion process of the first solder joint, set the fifth section parameters, including: The bonding ultrasonic power is 100~200 mA and the bonding pressure is 80~100 g; During the process of bonding the first solder joint using the thermosonic bonding method, the bonding temperature is 120~150℃.

[0009] Furthermore, the method of wrapping the ultrasonic bonding solder joints of the bare copper carrier by applying silver glue includes: For the ultrasonic bonding solder joints of the bare copper carrier, a die bonding machine or a dispensing machine is used to dispense conductive silver glue to wrap the ultrasonic bonding solder joints of the bare copper carrier; the specific parameters are as follows: dispensing height is 50~100 um; dispensing delay is 30~50 ms; tail cutting height is 500~1000 um; tail cutting speed is 10~30%.

[0010] Furthermore, after the silver glue is cured and before the chip and the frame pins are bonded and interconnected by thermosonic bonding, the method includes: The bare copper carrier with silver glue applied on it and the frame are placed in an oven at a preset temperature and baked for a preset time, with nitrogen injected during the baking period.

[0011] Furthermore, after the silver glue is cured, the chip and the frame pins are bonded and interconnected by using a thermosonic bonding method, including: After the silver glue is solidified, the bare copper carrier and the frame are plasma cleaned. The cleaned bare copper carrier and the frame are placed in the bonding area of ​​the thermosonic bonding machine; The chip and the frame pins are thermally ultrasonically bonded using metal bonding wires and a bonding whet; the bonding temperature is 180~200℃.

[0012] Furthermore, after the silver glue is cured, the chip and the frame pins are bonded and interconnected by using a thermosonic bonding method, and the method further includes: The complete bonded chip frame is plasma cleaned for the third time; The plastic sealing, electroplating, marking, cutting and packaging work are carried out in sequence to complete the final packaging of the chip.

[0013] A chip is manufactured by adopting the above-mentioned bare copper carrier thermosonic bonding and chip packaging method.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for thermal ultrasonic bonding and chip packaging of a bare copper carrier. This method uses a splitting knife to grind and remove the oxide layer of the bonding area of ​​the bare copper carrier to form a clean ground bonding area, directly performs thermal ultrasonic bonding in the ground bonding area to achieve chip / pin interconnection, then wraps the solder joints with silver glue and solidifies them, finally completing the chip-pin bonding. Physically grinding and removing the oxide layer fundamentally solves the problem of bare copper bonding oxidation and eliminates the need for traditional plating processes; silver glue wrapping can both isolate the solder joints from secondary oxidation and strengthen the plastic sealing material bonding interface, and the secondary bonding after solidification ensures that the silver glue does not interfere with the wire bonding. On the one hand, it completely gets rid of the precious metal plating and anti-oxidation gas protection system, greatly reducing the cost of frame materials and equipment modification; on the other hand, the oxide layer is broken to ensure bonding reliability, and the silver glue wrapping simultaneously improves the oxidation resistance of the solder joints and the bonding strength of the packaging structure, achieving the dual goals of high-reliability packaging and significant cost reduction on the bare copper carrier as a whole. The present invention provides a chip. Based on the above-mentioned bare copper carrier thermal ultrasonic bonding and chip packaging method, this chip achieves the dual effects of high-reliability packaging and cost optimization: bonding reliability is guaranteed due to the removal of the oxide layer and the protection of silver glue, and the packaging bonding force is improved. At the same time, the frame material cost and equipment investment cost are greatly reduced, and it has good promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of bonding the bare copper carrier through the oxide layer provided by an embodiment of the present invention; Figure 2 Schematic diagram of a bare copper carrier after breaking the oxide layer and bonding provided by an embodiment of the present invention; Figure 3 Schematic diagram of thermosonic bonding between a bare copper carrier and a chip / frame pin according to an embodiment of the present invention; Figure 4 Schematic diagram of dispensing glue on thermosonic bonding solder joints of a bare copper carrier provided by an embodiment of the present invention; Figure 5 Schematic diagram of the thermal ultrasonic bonding solder joints on a bare copper carrier after curing by dispensing glue according to an embodiment of the present invention; Figure 6 Schematic diagram of thermosonic bonding of a bare copper carrier chip according to an embodiment of the present invention; Figure 7 The present invention provides a flowchart of a bare copper carrier thermosonic bonding and chip packaging method.

[0016] The accompanying drawings are: 1. Chip; 2. Bare copper carrier; 3. Frame pins; 4. Chopping knife; 5. Grinding bonding area; 6. Carrier solder joints; 7. Metal bonding wires; 8. Silver glue dispensing head; 9. Silver glue; 10. Cured silver glue. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0018] As described in the background technology, the current thermosonic bonding and chip packaging methods are as follows: For a frame carrier coated with oxidation-resistant thin metal with a ground wire, the main process of thermal ultrasonic bonding and chip packaging is as follows: (1) The chip is bonded to the frame carrier by a bonding material (conductive silver glue, insulating glue, adhesive film, etc.) using a die bonding machine; (2) After bonding, the bonding material is cured by baking in an anti-oxidation oven; (3) After curing, plasma cleaning is performed to improve the thermal ultrasonic bonding performance of the chip and frame surface; (4) A thermal ultrasonic bonding machine is used to perform thermal ultrasonic bonding on the chip and frame carrier, the chip and frame pins, and the frame carrier and frame pins according to the wire bonding diagram. The product is generally only put on the machine once, and the thermal ultrasonic bonding of multiple interconnecting wires is completed in sequence. Among them, the bonding area of ​​the frame carrier is located in the area of ​​the carrier's oxidation-resistant thin metal layer; (5) After thermal ultrasonic bonding, the packaging process is completed according to the main processes of plasma cleaning, plastic sealing, electroplating, printing, punching / cutting, etc.

[0019] For a frame carrier with a ground wire and not coated with oxidation-resistant thin metal, the main process of thermal ultrasonic bonding and chip packaging is as follows: (1) The chip is bonded to the frame carrier by a bonding material (conductive silver glue, insulating glue, adhesive film, etc.) using a die bonding machine; (2) After bonding, the bonding material is cured by baking in an anti-oxidation oven; (3) After curing, plasma cleaning is performed to improve the thermal ultrasonic bonding performance of the chip and frame surface; (4) The thermal ultrasonic bonding machine is modified to seal the bonding area, and the sealed area is continuously filled with an anti-oxidation reduction gas (such as a nitrogen-hydrogen mixture), and then the thermal ultrasonic bonding between the chip, frame carrier, and frame pins is completed according to the wire bonding diagram, where the bonding area of ​​the frame carrier is located in the bare copper carrier area; (5) After thermal ultrasonic bonding, the packaging process is completed according to the main processes such as plasma cleaning, plastic sealing, electroplating, printing, punching / cutting, etc. It can be seen that the main problems with the above two situations and technical methods are: First, for the thermal ultrasonic bonding and chip packaging methods of frame carriers plated with oxidation-resistant thin metals with ground wire requirements, the bonding strength between the oxidized thin metal (such as silver) and the plastic packaging material is not as good as the bonding strength between bare copper and the plastic packaging material, which affects the reliability after packaging, and the nickel-palladium-gold plating will lead to a significant increase in the frame cost; Second, for the thermal ultrasonic bonding and chip packaging methods of frame carriers not plated with oxidation-resistant thin metals with ground wire requirements, the sealing modification of the bonding area of ​​the ultrasonic bonding machine and the prevention of redox gases increase the packaging cost.

[0020] To address the aforementioned issues, a method for thermosonic bonding and chip packaging is provided for a frame carrier that requires a ground wire and is not coated with an oxidation-resistant thin metal. The method provided in this embodiment does not require sealing and modifying the bonding area of ​​a thermosonic bonding machine. Instead, it improves upon the method for thermosonic bonding and chip packaging of a frame carrier coated with an oxidation-resistant thin metal. By treating the bare copper carrier for oxide layer breakage, the effect of copper carrier oxidation on the strength and stability of thermosonic bonding is reduced. The chip and frame carrier, and the frame carrier and frame pins are interconnected by first performing thermosonic bonding of the ground wire, dispensing glue, and curing the glue. Finally, thermosonic bonding is performed to interconnect the chip and frame pins.

[0021] Exemplarily, this embodiment provides a bare copper carrier thermal ultrasonic bonding and chip packaging method, including a bare copper carrier breaking oxide layer bonding method, a bare copper carrier and chip / frame pin thermal ultrasonic bonding method, a bare copper carrier thermal ultrasonic bonding solder joint dispensing method and a bare copper carrier chip packaging method, through the bare copper carrier breaking oxide layer after thermal ultrasonic bonding, dispensing and encapsulating the bare copper carrier ultrasonic bonding solder joints, and three-time on-machine bonding chip packaging method to achieve bare copper carrier oxidation thermal ultrasonic bonding and chip packaging, the specific steps are as follows Figure 7 As shown: S1. Using a wedge grinding bonding method, the oxide layer of the bare copper carrier bonding area of ​​the frame is broken to form a grinding bonding area on the bare copper carrier bonding area; the chip is bonded to the frame; S2. Bonding the bare copper carrier to the chip and the frame pins respectively using thermosonic bonding in the grinding bonding area of ​​the bare copper carrier; S3, wrapping the ultrasonic bonding solder joints of the bare copper carrier by dispensing silver glue; S4. After the silver glue is cured, the chip and the frame pins are bonded and interconnected using a thermosonic bonding method.

[0022] In the embodiment, the specific inventive concept is as follows: First, bare copper carrier oxide layer breaking bonding method: The bare copper carrier 2 is very easy to be oxidized at high temperature before thermosonic bonding (baking at above 150℃ for adhesive curing) and during thermosonic bonding (bonding at above 150℃). The oxide layer hinders the metal interconnection between the bonding metal wire and the bare copper carrier 2, resulting in too small a thrust force at the bonding solder joint. Figure 1As shown, the frame (including the bare copper carrier 2 and the frame pins 3) with the chip 1 attached is placed in the bonding area of ​​the thermal ultrasonic bonding machine, and a splitter 4 without a bonding metal wire is used. The grinding function of the thermal ultrasonic bonding machine is turned on, and the splitter 4 grinds and bonds the oxide layer in the bonding area of ​​the bare copper carrier 2. The bonding method for breaking the oxide layer of the bare copper carrier 2 requires: the temperature of the bonding area of ​​the thermal ultrasonic bonding machine is 100~120℃; the bonding pressure of the splitter 4 is 60~80g; the bonding power of the splitter 4 is 120~140mA; the grinding amplitude of the splitter 4 is 6~8um; and the grinding cycle is 5~8 times. At a lower bonding temperature, the surface oxide layer can be destroyed by physically ultrasonic grinding the oxide layer of the bare copper carrier 2 by the splitter 4, thereby improving the thermal ultrasonic bonding strength and stability of the bare copper carrier 2. As Figure 2 As shown, a grinding bonding area 5 with broken oxide layer is formed on the surface of the bare copper carrier 2 by grinding; wherein the grinding bonding area 5 is a grinding mark formed on the bonding area of ​​the bare copper carrier after the wedge grinding bonding, covering the bonding area of ​​the bare copper carrier 2.

[0023] (2) Thermosonic bonding method between bare copper carrier and chip / frame pins: After the splitter 4 destroys the oxide layer in the bonding area of ​​the bare copper carrier 2, the bonding performance of the bare copper bonding area is improved, but the residual oxide still affects the bonding strength and stability. The bonding strength will be improved in the bonding solder joint dispensing method, but the bonding stability needs to be solved in this process. The destruction of the oxide layer in the bonding area of ​​the bare copper carrier 2 can significantly improve the bonding strength and stability of the carrier solder joint 6 of the bare copper carrier 2; however, due to the presence of residual oxide, the hardness of the bonding area of ​​the bare copper carrier 2 is enhanced, and the second solder joint bonding frequently issues bonding wire shrinkage alarms, and the bonding stability of the second solder joint of the bare copper carrier 2 cannot be effectively improved. Therefore, when the chip 1 is thermally ultrasonically bonded to the frame carrier, and the frame carrier is thermally ultrasonically bonded to the frame pin 3, it is necessary to bond the carrier solder joint 6 (first solder joint) to the frame carrier, and the second solder joint to the chip 1 or the frame pin 3, as shown in the following example. Figure 3 As shown in the figure, the bonding parameters for carrier solder joint 6 need to be set according to the five-stage parameter method: the bonding temperature is 120-150°C. The first to third stages are mainly for solder ball forming, with bonding ultrasonic power of 80-120mA, bonding pressure of 7-12g, and grinding bonding amplitude of 2-3μm. The fourth stage uses high power and low pressure parameters to promote the growth of intermetallic compounds in the solder joint, with bonding ultrasonic power of 100-200mA and bonding pressure of 10-14g. The fifth stage uses high power and high pressure parameters to complete the bonding of carrier solder joint 6, with bonding ultrasonic power of 100-200mA and bonding pressure of 80-100g.

[0024] (3) Glue dispensing method for bare copper carrier thermal ultrasonic bonding solder joints: After completing the thermal ultrasonic bonding between the chip 1 and the frame carrier, and between the frame carrier and the frame pin 3, the bonding strength of the carrier solder joint 6 is affected by the residual oxide in the bonding area of ​​the bare copper carrier 2, and there is a risk of cold solder joints. It is necessary to reinforce the carrier solder joint 6 on the bare copper carrier 2 with glue. Figure 4 As shown, conductive silver glue 9 is dispensed using a die bonding machine or dispensing machine, with silver glue dispensing head 8 applying the dots. Key dispensing parameters are: dispensing height 50-100 μm; dispensing delay 30-50 ms; tail cutting height 500-1000 μm; and tail cutting speed 10-30%. After dispensing all solder joints 6 on the bare copper carrier 2, the device is placed in a 175°C oven for baking. Nitrogen is injected during baking to prevent oxidation of the chip 1 and the frame.

[0025] (4) Bare copper carrier chip packaging method: The bare copper carrier 2 chip 1 packaging method includes the entire packaging process including the bare copper carrier oxide layer breaking bonding method, the bare copper carrier and chip / frame pin thermal ultrasonic bonding method, and the bare copper carrier ultrasonic bonding solder joint gluing method described in this embodiment. In comparison, the general chip packaging process is: chip bonding, baking and curing, plasma cleaning, thermal ultrasonic bonding, plasma cleaning, plastic sealing, electroplating, printing, punching / cutting; while the bare copper carrier chip packaging method process of this embodiment is: chip bonding, baking and curing, plasma cleaning, bare copper carrier oxide layer breaking bonding (first machine bonding), bare copper carrier and chip / frame pin thermal ultrasonic bonding (second machine bonding), bare copper carrier ultrasonic bonding solder joint gluing, baking and curing, plasma cleaning, chip and frame pin thermal ultrasonic bonding (third machine bonding), plasma cleaning, plastic sealing, electroplating, printing, punching / cutting. After the third machine bonding is completed, as Figure 5 As shown, the chip 1 is bonded to the frame carrier, the frame pin 3, and the frame carrier to the frame pin 3. After the silver glue is applied, it needs to be baked and solidified. The solidified silver glue 10 wraps the carrier solder joint 6 to achieve a high bonding strength connection between the carrier solder joint 6 and the bare copper carrier 2. Figure 6 As shown, after completing the thermosonic bonding and glue curing of the bare copper carrier 2, a thermosonic bonding machine is used to complete the thermosonic bonding of the chip 1 and the frame pins 3, thereby achieving complete electrical interconnection of the chip 1.

[0026] In summary, this embodiment provides a bare copper carrier thermosonic bonding and chip packaging method, which has the following advantages: This method effectively achieves thermosonic bonding of bare copper carriers in the absence of redox gases. Key innovations include bonding through oxide layer breakage on the bare copper carrier, thermosonic bonding between the bare copper carrier and chip / frame pins, and dispensing glue at the thermosonic bonding solder joints. This method offers the advantages of lower frame costs compared to carriers plated with thin, oxidation-resistant metal frames, and lower equipment costs compared to bonding methods that require sealing and modifying the bonding area. It also enables bare copper carrier frames to be compatible with both ground-wire-required and non-ground-required chip packaging.

[0027] The method provided by the present invention is further explained below with reference to specific embodiments: A SOP8 chip package requires thermosonic bonding of the chip 1 to the frame carrier and frame pins 3, and also requires thermosonic bonding of the frame carrier to the frame pins 3. The frame carrier has two bonding areas, interconnected by metal wires 7. The frame is a single-ring plated bare copper carrier SOP8 frame. The implementation steps for thermosonic bonding of the bare copper carrier 2 and the chip 1 package are as follows: Step 1: Use a die bonding machine to bond the chip 1 to the bare copper carrier 2 of the frame, and the bonding material is conductive silver glue 9; Step 2: Use a nitrogen oven to bake the frame with the chip 1 attached to solidify the conductive silver glue 9; Step 3: Plasma clean the frame with the chip 1 attached to improve the bonding performance of the chip 1 and the frame bonding area; Step 4: Place the frame with chip 1 attached to the bonding area of ​​the thermosonic bonding machine. Use a bonding blade 4 to perform a splitter-grinding bond on the two bonding areas of the bare copper carrier 2. Set the bonding area temperature of the ultrasonic bonding machine to 100°C. Other key bonding parameters are: bonding pressure of 60g, bonding power of 120mA, grinding amplitude of 6µm, and 5 grinding cycles. After the bonding is completed, remove the frame with chip 1 from the thermosonic bonding machine. Step 5: Place the frame with the chip 1 bonded after grinding and bonding with a splitter for the second time in the bonding area of ​​the thermosonic bonding machine, and use a 20um gold wire and a bonding splitter 4 to bond the bare copper carrier 2 to the chip 1 and the frame pin 3. The bare copper carriers 2 are all bonded as carrier solder joints 6, and the bonding temperature is set to 120°C. The five-stage parameter setting of the carrier solder joint 6 is: the first to third sections have an ultrasonic bonding power of 80mA, a bonding pressure of 7g, and a grinding bonding amplitude of 2um; the fourth section has an ultrasonic bonding power of 100mA and a bonding pressure of 10g; the fifth section has an ultrasonic bonding power of 100mA and a bonding pressure of 80g. After the bare carrier is thermally ultrasonically bonded, remove the frame with the chip 1 from the thermosonic bonding machine again; Step 6: Place the bare carrier thermosonic bonded chip 1 frame in the dispensing area of ​​the die bonder. Use the same silver glue 9 as the die bonder to dispense glue at two thermosonic bonding points on the carrier. Main parameters are: dispensing height 50μm, dispensing delay 30ms, tail cutting height 500μm, and tail cutting speed 10%. After dispensing, wrap the silver glue 9 around the carrier thermosonic bonding points. Place the chip 1 frame in a nitrogen oven and bake at 175°C for 2.5 hours. Step 7: After the above baking is completed, the chip 1 frame is subjected to a second plasma cleaning to improve the bonding performance of the chip 1 and the frame bonding area; Step 8: Place the chip 1 frame in the bonding area of ​​the thermosonic bonding machine for the third time. Use 20µm gold wire and bonding blade 4 to perform thermosonic bonding on the chip 1 and the frame pins 3. Set the bonding temperature to 200°C. Step 9: After the aforementioned thermal ultrasonic bonding of the chip 1 and the frame pin 3 is completed, the complete bonded chip 1 frame is subjected to a third plasma cleaning; Step 10: Complete the plastic encapsulation, electroplating, marking, and punching packaging work in sequence to achieve SOP8 chip 1 packaging.

[0028] Example 2: A QFN20 chip package requires thermosonic bonding of chip 1 to the frame carrier and frame pin 3, and also requires thermosonic bonding of the frame carrier to frame pin 3. The frame carrier has four bonding areas, interconnected by copper wire. The frame is a single-ring plated bare copper carrier QFN20 frame. The implementation steps for thermosonic bonding of the bare copper carrier 2 and chip 1 packaging are as follows: Step 1: Use a die bonding machine to bond the chip 1 to the bare copper carrier 2 of the frame, and use insulating glue as the bonding material; Step 2: Use a nitrogen oven to bake the frame with the chip 1 attached to solidify the conductive silver glue 9; Step 3: Plasma clean the frame with the chip 1 attached to improve the bonding performance of the chip 1 and the frame bonding area; Step 4: Place the frame with chip 1 attached to the bonding area of ​​the thermosonic bonding machine. Use a bonding blade 4 to bond the four bonding areas of the bare copper carrier 2. Set the bonding area temperature of the ultrasonic bonding machine to 120°C. Other key bonding parameters are: bonding pressure of 80g, bonding power of 140mA, grinding amplitude of 8µm, and 8 grinding cycles. After bonding, remove the frame with chip 1 from the thermosonic bonding machine. Step 5: Place the frame with the chip 1 bonded after grinding and bonding with a splitter for the second time in the bonding area of ​​the thermosonic bonding machine, and use 20um copper wire and a bonding splitter 4 to bond the bare copper carrier 2 to the chip 1 and the frame pin 3. The bare copper carriers 2 are all bonded as carrier solder joints 6, and the bonding temperature is set to 150°C. The five-stage parameter settings of the carrier solder joints 6 are: the first to third sections have an ultrasonic bonding power of 120mA, a bonding pressure of 12g, and a grinding bonding amplitude of 3um; the fourth section has an ultrasonic bonding power of 200mA and a bonding pressure of 14g; the fifth section has an ultrasonic bonding power of 200mA and a bonding pressure of 100g. After the bare carrier is thermally ultrasonically bonded, remove the frame with the chip 1 from the thermosonic bonding machine again; Step 6: Place the bare carrier thermosonic bonded chip 1 frame in the dispensing area of ​​the die bonder. Use the same silver glue 9 as the die bonder to dispense glue at two thermosonic bonding points on the carrier. Main parameters are: dispensing height 100μm, dispensing delay 50ms, tail cutting height 1000μm, and tail cutting speed 30%. After dispensing, wrap the silver glue 9 around the carrier thermosonic bonding points. Place the chip 1 frame in a nitrogen oven and bake at 175°C for 2.5 hours. Step 7: After the above baking is completed, the chip 1 frame is subjected to a second plasma cleaning to improve the bonding performance of the chip 1 and the frame bonding area; Step 8: Place the chip 1 frame in the bonding area of ​​the thermosonic bonding machine for the third time. Use 20µm copper wire and bonding blade 4 to perform thermosonic bonding on the chip 1 and the frame pins 3. Set the bonding temperature to 190°C. Step 9: After the aforementioned thermal ultrasonic bonding of the chip 1 and the frame pin 3 is completed, the complete bonded chip 1 frame is subjected to a third plasma cleaning; Step 10: Complete the plastic encapsulation, electroplating, marking, and cutting packaging work in sequence to achieve the QFN20 chip 1 packaging.

[0029] Example 3: A DFN6 chip package requires thermosonic bonding of the chip 1 to the frame carrier and the frame pins 3. The frame carrier has a bonding area where silver alloy wires are used for interconnection. The frame is a single-ring plated bare copper carrier DFN6 frame. The steps for thermosonic bonding of the bare copper carrier 2 and the chip 1 package are as follows: Step 1: Use a die bonding machine to bond the chip 1 to the bare copper carrier 2 of the frame, and use adhesive film as the bonding material; Step 2: Use a nitrogen oven to bake the frame with the chip 1 attached to solidify the conductive silver glue 9; Step 3: Plasma clean the frame with the chip 1 attached to improve the bonding performance of the chip 1 and the frame bonding area; Step 4: Place the frame with chip 1 attached to the bonding area of ​​the thermosonic bonding machine. Use bonding blade 4 to perform splitting and grinding bonding on one bonding area of ​​the bare copper carrier 2. Set the bonding area temperature of the ultrasonic bonding machine to 110°C. Other key bonding parameters are: bonding pressure of 75g, bonding power of 130mA, grinding amplitude of 7µm, and grinding cycle 6 times. After bonding, remove the frame with chip 1 from the thermosonic bonding machine. Step 5: Place the frame with the chip 1 bonded after the splitter grinding bonding in the bonding area of ​​the thermosonic bonding machine for the second time, and use 25um silver alloy wire and bonding splitter 4 to bond the bare copper carrier 2 and chip 1. The bare copper carrier 2 is used as the carrier solder joint 6 for bonding, and the bonding temperature is set to 135°C. The five-stage parameter setting of the carrier solder joint 6 is: the first to third sections of bonding ultrasonic power are 115mA, the bonding pressure is 10g, and the grinding bonding amplitude is 2.5um; the fourth section of bonding ultrasonic power is 160mA, and the bonding pressure is set to 12g; the fifth section of bonding ultrasonic power is 150mA, and the bonding pressure is 90g. After the bare carrier is thermally ultrasonically bonded, remove the frame with the chip 1 from the thermosonic bonding machine again; Step 6: Place the bare carrier thermosonic bonded chip 1 frame in the dispensing area of ​​the die bonder. Use the same silver glue 9 as the die bonder to dispense glue at two thermosonic bonding points on the carrier. Main parameters are: dispensing height 800μm, dispensing delay 40ms, tail cutting height 800μm, and tail cutting speed 20%. After dispensing, wrap the silver glue 9 around the carrier thermosonic bonding points. Place the chip 1 frame in a nitrogen oven and bake at 175°C for 2.5 hours. Step 7: After the above baking is completed, the chip 1 frame is subjected to a second plasma cleaning to improve the bonding performance of the chip 1 and the frame bonding area; Step 8: Place the chip 1 frame in the bonding area of ​​the thermosonic bonding machine for the third time. Use 20µm silver alloy wire and bonding blade 4 to perform thermosonic bonding on the chip 1 and the frame pins 3. Set the bonding temperature to 200°C. Step 9: After the aforementioned thermal ultrasonic bonding of the chip 1 and the frame pin 3 is completed, the complete bonded chip 1 frame is subjected to a third plasma cleaning; Step 10: Complete the plastic encapsulation, electroplating, marking, and cutting packaging work in sequence to achieve the packaging of DFN6 chip 1.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and disclosed concepts of the present invention, should be covered by the scope of protection of the present invention.

[0032] The further detailed description disclosed does not mean that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the scope of protection of the present invention determined by the submitted claims.

Claims

1. A bare copper carrier thermosonic bonding and chip packaging method, characterized in that: include: The oxide layer of the bare copper carrier bonding area of ​​the frame is broken by a wedge grinding bonding method, so that a grinding bonding area is formed on the bare copper carrier bonding area; the chip is bonded to the frame; In the grinding bonding area of ​​the bare copper carrier, the bare copper carrier is bonded and interconnected with the chip and the frame pins respectively by using a thermosonic bonding method; The bare copper carrier ultrasonic bonding solder joints are wrapped by dispensing silver glue; After the silver glue is cured, the chip and the frame pins are bonded and interconnected using thermosonic bonding.

2. The bare copper carrier thermosonic bonding and chip packaging method according to claim 1, characterized in that: Before removing the oxide layer of the bare copper carrier bonding area of ​​the frame by using the wedge grinding bonding method, the method includes: The frame with the chip attached is placed in the bonding area of ​​the thermosonic bonding machine.

3. The bare copper carrier thermosonic bonding and chip packaging method according to claim 1, characterized in that: The method of using a wedge grinding bonding method to break the oxide layer of the bare copper carrier bonding area of ​​the frame includes: A splitter was used to grind and bond the oxide layer in the bonding area of ​​the bare copper carrier to form a grinding bonding area of ​​the bare copper carrier. The temperature of the bonding area of ​​the ultrasonic bonding machine was 100-120 °C, the splitter bonding pressure was 60-80 g, the splitter bonding power was 120-140 mA, the splitter grinding amplitude was 6-8 um, and the grinding cycle was 5-8 times.

4. The method for thermosonic bonding and chip packaging of a bare copper carrier according to claim 1, characterized in that: The method comprises: bonding the bare copper carrier to the chip and the frame pins respectively by using a thermosonic bonding method in the grinding bonding area of ​​the bare copper carrier. Bonding a first solder joint in the ground bonding area of ​​the bare copper carrier using thermosonic bonding; On the chip or the frame pin, a second solder joint is bonded by using a thermosonic bonding method to achieve bonding interconnection between the bare copper carrier and the chip and the frame pin respectively.

5. The bare copper carrier thermosonic bonding and chip packaging method according to claim 4, characterized in that: The process of bonding the first solder joint in the ground bonding area of ​​the bare copper carrier by using a thermosonic bonding method includes: The bonding method of the first solder joint is set using a five-stage parameter setting method, as follows: For the solder ball forming process of the first solder joint, set the parameters of the first to third stages, including: The bonding ultrasonic power is 80~120 mA; the bonding pressure is 7~12 g; the grinding bonding amplitude is 2~3 um; For the intermetallic compound growth process of the first solder joint, set the fourth section parameters, including: The bonding ultrasonic power is 100~200 mA; the bonding pressure is 10~14 g; For the bonding completion process of the first solder joint, set the fifth section parameters, including: The bonding ultrasonic power is 100~200 mA and the bonding pressure is 80~100 g; During the process of bonding the first solder joint using the thermosonic bonding method, the bonding temperature is 120~150℃.

6. The method for thermosonic bonding and chip packaging of a bare copper carrier according to claim 1, characterized in that: The method of wrapping the ultrasonic bonding solder joints of the bare copper carrier by dispensing silver glue comprises: For the ultrasonic bonding solder joints of the bare copper carrier, a die bonding machine or a dispensing machine is used to dispense conductive silver glue to wrap the ultrasonic bonding solder joints of the bare copper carrier; the specific parameters are as follows: dispensing height is 50~100 um; dispensing delay is 30~50 ms; tail cutting height is 500~1000 um; tail cutting speed is 10~30%.

7. The method for thermosonic bonding and chip packaging of a bare copper carrier according to claim 1, characterized in that: After the silver glue is cured, before the chip and the frame pins are bonded and interconnected by using a thermosonic bonding method, the method includes: The bare copper carrier with silver glue applied on it and the frame are placed in an oven at a preset temperature and baked for a preset time, with nitrogen injected during the baking period.

8. The method for thermosonic bonding and chip packaging of a bare copper carrier according to claim 1, characterized in that: After the silver glue is cured, the chip and the frame pins are bonded and interconnected by using a thermosonic bonding method, including: After the silver glue is solidified, the bare copper carrier and the frame with the silver glue applied are plasma cleaned; The cleaned bare copper carrier and the frame are placed in the bonding area of ​​the thermosonic bonding machine; The chip and the frame pins are thermally ultrasonically bonded using metal bonding wires and a bonding whet; the bonding temperature is 180~200℃.

9. The method for thermosonic bonding and chip packaging of a bare copper carrier according to claim 1, characterized in that: After the silver glue is cured, the chip and the frame pins are bonded and interconnected by using a thermosonic bonding method, and the method further includes: The complete bonded chip frame is plasma cleaned for the third time; The plastic sealing, electroplating, marking, cutting and packaging work are carried out in sequence to complete the final packaging of the chip.

10. A chip, characterized in that: The chip is manufactured by the bare copper carrier thermosonic bonding and chip packaging method according to any one of claims 1 to 9.

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