A new silicon microphone chip packaging process

Abstract

The application discloses a novel silicon microphone packaging process, S1, ASIC and MEMS packaging and curing; S2, copper wire welding, the circuit of the MEMS chip and the circuit of the ASIC chip and the circuit of the PCB chip; S3, dispensing covering and dispensing curing; S4, tin paste scribing, tin paste is coated on the PCB tin paste pad through a tin paste scribing machine; S5, shell mounting and shell reflow soldering, the metal shell is mounted on the tin paste coated pad through the mounting head of the chip mounter to suck the metal shell; S6, marking, the product batch number is printed on the metal shell through the laser marking machine; S7, PCB board splitting and packaging, the whole PCB is split into single products through a water cutting machine, and then the single products are packaged through a packaging machine; compared with the traditional palladium-gold and nickel plating layer and gold wire cooperation, the silver plating layer and the first copper wire are arranged, the production and processing cost is reduced, meanwhile, the cooperation of the copper wire and the silver plating layer is more firm, and the stability of the connection can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microphone equipment, in particular to a novel silicon microphone packaging process. BACKGROUND

[0002] A microphone, also known as a microphone, is a device that converts sound signals into electrical signals. There are dynamic, capacitive, electret and recently emerging silicon microphones. Silicon microphones include silicon microphone packaging, which is a housing for installing semiconductor integrated circuit chips. It plays a role in placing, fixing, sealing, protecting chips and enhancing electrical performance. It is also a bridge between the internal world of the chip and the external circuit. The contacts on the chip are connected to the pins of the packaging shell by wires. These pins are connected to other devices through wires on the printed board. Therefore, packaging plays an important role in CPU and other LSI integrated circuits. When packaging silicon microphone packaging, packaging structure is needed.

[0003] Currently, the mainstream silicon microphone packaging process is to install ASIC chips and MEMS chips separately. After the ASIC chip is bonded and cured, the MEMS chip is installed and cured again. When cutting, it also needs to be done separately, which increases the processing time and material cost. Therefore, we need to propose a novel silicon microphone packaging process. SUMMARY

[0004] The purpose of the present application is to provide a novel silicon microphone packaging process, which has the advantages of reducing processing cost and improving efficiency to solve the problems raised in the background.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a novel silicon microphone packaging method, comprising the following steps:

[0006] S1, ASIC and MEMS packaging and curing, a steel mesh plate with ASIC opening and MEMS opening is sleeved on the PCB board, then the PCB board with the steel mesh plate is applied to the glue machine for glue application, the glue flows into the PCB from the ASIC opening and the MEMS opening, then the PCB board after glue application is subjected to ASIC and MEMS packaging and curing;

[0007] S2, copper wire welding, the circuit of the MEMS chip is connected to the circuit of the ASIC chip and the circuit of the PCB chip through copper wire conduction;

[0008] S3, glue injection and curing, silicon glue is sprayed on the surface of the ASIC chip and the PCB gold wire connection, which plays a protective role; the silicon glue on the surface of the ASIC chip and the PCB gold wire connection is baked and cured;

[0009] S4, tin paste, tin paste is coated on the PCB tin paste pad by tin paste machine;

[0010] S5, shell mounting and shell reflow soldering, the shell is mounted on the tin paste coated pad by the suction head of the chip mounter; the tin paste is reflowed and solidified to fix the shell and protect the internal copper wire and chip of the product;

[0011] S6, marking, the product batch number is printed on the shell by the laser marking machine;

[0012] S7, PCB board splitting and packaging, the whole PCB board is cut into single products by a water cutting machine, and then the single products are packaged by a packaging machine.

[0013] Preferably, a new silicon microphone packaging process includes a substrate, a circuit board body embedded on the top of the substrate, an ASIC chip mounted on one side of the top of the circuit board body, and a MEMS chip mounted on the other side of the top of the circuit board body.

[0014] Preferably, a PCB wire binding reel is arranged on the top of the circuit board body and away from the MEMS chip, and a first copper wire is connected to the ASIC chip, with one end of the first copper wire connected to the PCB wire binding reel.

[0015] Preferably, a cover plate is mounted on the top of the substrate, a through hole is formed on the top of the cover plate, and the bottom of the cover plate is bonded to the top of the substrate by glue.

[0016] Preferably, welding points are arranged on the top of the ASIC chip and the MEMS chip, and a second copper wire is arranged between the ASIC chip and the MEMS chip, with both ends of the second copper wire connected to the top of the ASIC chip and the MEMS chip by welding points, respectively.

[0017] Preferably, the PCB wire binding reel includes a welding disc arranged on the top of the circuit board body and a wire binding arranged on the surface of one side of the circuit board body.

[0018] Preferably, the top of the ASIC chip is connected to the first copper wire by a welding point, and one end of the first copper wire away from the ASIC chip is connected to the surface of the welding disc.

[0019] Preferably, a silver plating layer is coated on the surface of the welding disc, and the thickness of the silver plating layer is 20-30 microns.

[0020] Preferably, a glue layer is coated on the bottom of the ASIC chip and the MEMS chip, and the bottom of the ASIC chip and the MEMS chip is connected to the surface of the circuit board body by the glue layer.

[0021] Compared with the prior art, the application has the beneficial effects that:

[0022] 1、The application can fix the position of the ASIC chip and the MEMS chip on the substrate by setting the steel mesh, and then the ASIC chip and the MEMS chip are respectively pasted and fixed on the substrate, and then curing is carried out, compared with the existing process of separately installing the ASIC chip and the MEMS chip, time is saved, and the processing steps are simplified.

[0023] 2、Compared with the traditional palladium-gold and nickel plating layer and gold wire cooperation, the application reduces the production and processing cost, and the cooperation of the copper wire and the silver plating layer is more firm, which can improve the stability of the connection.

[0024] 3、The application sets the substrate, which can install and support the ASIC chip and the MEMS chip, and can also protect the bottom of the MEMS chip and the ASIC chip; the cover plate can protect the MEMS chip and the ASIC chip on the top of the substrate, thereby improving the protection effect of the ASIC chip and the MEMS chip.

[0025] 4、The application sets the welding point for conveniently connecting the second copper wire with the ASIC chip and the MEMS chip, and sets the glue layer for fixing the ASIC chip and the MEMS chip on the circuit board body, thereby improving the stability of the ASIC chip and the MEMS chip. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the application;

[0027] Figure 2 It is a three-dimensional structural schematic diagram of the ASIC chip of the application;

[0028] Figure 3 It is a front view of the PCB wire binding reel of the application;

[0029] Figure 4 It is a method flowchart of the application;

[0030] Figure 5 It is a structural schematic diagram of the steel mesh of the application.

[0031] In the figure: 1, substrate; 2, circuit board body; 3, ASIC chip; 4, MEMS chip; 5, PCB wire binding reel; 6, first copper wire; 7, cover plate; 8, through hole; 9, welding point; 10, second copper wire; 11, welding disc; 12, wire binding; 13, silver plating layer; 14, glue layer. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0033] Embodiment 1

[0034] Please refer to Figure 4 and 5 The present application provides a technical solution: a novel silicon microphone packaging process, comprising the following steps:

[0035] S1, ASIC and MEMS packaging and curing, a steel mesh plate with ASIC openings and MEMS openings is sleeved on a PCB board, then the PCB board with the steel mesh plate is applied to a glue applying machine for glue applying, the glue flows into the PCB from the ASIC openings and the MEMS openings, then the ASIC and MEMS packaging is performed on the PCB after glue applying, and curing is performed;

[0036] S2, copper wire welding, the circuit of the MEMS chip is connected with the circuit of the ASIC chip and the circuit of the PCB chip through copper wire conduction;

[0037] S3, glue spraying and curing, the silicone glue at the surface of the ASIC chip and the gold wire connection of the PCB is sprayed, which plays a protection role; the silicone glue at the surface of the ASIC chip and the gold wire connection of the PCB is baked and cured;

[0038] S4, tin paste drawing, tin paste is applied on the PCB tin paste pad through a tin paste drawing machine;

[0039] S5, shell mounting and shell reflow soldering, the metal shell is attracted by a mounting head of a chip mounter and is mounted on the tin paste coated pad; the tin paste is reflowed and cured to fix the shell and protect the internal copper wire and chip of the product;

[0040] S6, marking, the product batch number is printed on the metal shell by a laser marking machine through laser printing;

[0041] S7, PCB board splitting and packaging, a water cutting machine is adopted, the whole PCB board is cut into single products by a cutting knife, and then the single products are packaged by a packaging machine.

[0042] In step S4, the tin paste is a gray paste. The solder paste is a new type of welding material developed with SMT. It is a paste-like mixture formed by mixing solder powder, flux, and other surface active agents and thixotropic agents. It is mainly used for welding electronic components such as PCB surface resistors, capacitors, and ICs in the SMT industry. It can initially adhere electronic components to a designated position. At the welding temperature, with the evaporation of solvents and part of the additives, the welded components are welded to the printed circuit pads to form a permanent connection.

[0043] In addition, the dispensing and curing in step S3 require the use of a dispensing machine and an oven, respectively. The dispensing machine, also known as a glue applicator, glue dropper, glue dispenser, or glue filler, is an automatic machine that controls fluid and applies it to the surface or interior of a product. It can achieve three-dimensional and four-dimensional path dispensing, precise positioning, and accurate glue control without stringing, leaking, or dripping. The dispensing machine is mainly used for precisely dispensing, injecting, coating, or dripping glue, paint, and other liquids to the exact position of each product in the product process. It can be used to achieve dotting, line drawing, circular, or arc-shaped.

[0044] Further, the ASIC chip 3 refers to an integrated circuit chip technology for specific applications. In the integrated circuit industry, it is considered an integrated circuit designed for a specific purpose. All interface modules of the ASIC chip 3 technology are connected to a matrix backplane. Through direct forwarding from ASIC chip 3 to ASIC chip 3, communication between multiple modules can be performed simultaneously.

[0045] The MEMS chip 4 refers to a micro-electro-mechanical system, also known as a micro-electronic mechanical system, micro-system, or micro-mechanical system. It is a high-tech device with a size of a few millimeters or even smaller. The internal structure of the micro-electro-mechanical system is generally in the order of microns or even nanometers, and it is an independent intelligent system. The micro-electro-mechanical system is developed based on microelectronics technology, combining techniques such as lithography, etching, thin film, LIGA, silicon microfabrication, non-silicon microfabrication, and precision machining to produce high-tech electronic mechanical devices. The micro-electro-mechanical system is a micro device or system that integrates micro sensors, micro actuators, micro mechanical structures, micro power sources, signal processing and control circuits, high-performance electronic integrated devices, interfaces, communication, and other functions.

[0046] The shell of the oven is generally made of thin steel plate with a surface baking finish. The working chamber is made of high-quality structural steel plate. The shell and the working chamber are filled with aluminum silicate fibers. The heater is installed at the bottom, or it can be placed at the top or on both sides. The temperature control instrument uses a digital intelligent meter.

[0047] In addition, the copper wire welding mentioned in step S2 needs to use a bonder, which is a device for accurately positioning the IC chip on the LCD glass and binding. The whole machine is composed of PLC+HMI control core, and the image automatic alignment system completes the alignment data calculation of the target object. After the product completes the alignment and pre-pressing, it is transmitted to the bonder for binding and pressing.

[0048] Embodiment 2

[0049] Please refer to Figures 1-3 The difference between this embodiment 2 and embodiment 1 is that:

[0050] This embodiment also provides a new type of silicon microphone packaging process, which comprises a substrate 1, a circuit board body 2 embedded on the top of the substrate 1, an ASIC chip 3 installed on one side of the top of the circuit board body 2, and a MEMS chip 4 installed on the other side of the top of the circuit board body 2. By providing the substrate 1, a groove adapted to the circuit board body 2 is formed on the top of the substrate 1, and the circuit board body 2 is embedded on the top of the substrate 1 through the groove.

[0051] The PCB binding wire reel 5 comprises a welding disc 11 and a binding wire 12. The welding disc 11 is arranged on the top of the circuit board body 2, and the binding wire 12 is arranged on the surface of one side of the circuit board body 2. The top of the ASIC chip 3 is connected with the first copper wire 6 through the welding point 9, and the end of the first copper wire 6 away from the ASIC chip 3 is connected with the surface of the welding disc 11. The surface of the welding disc 11 is coated with a silver plating layer 13, and the thickness of the silver plating layer 13 is 20-30 microns. By providing the silver plating layer 13 and the first copper wire 6, compared with the traditional cooperation of palladium-gold and nickel plating layer and gold wire, the cost of production and processing is reduced.

[0052] The silver plating layer 13 is much cheaper than gold plating, and has very high electrical conductivity, light reflectivity and chemical stability to organic acids and bases. The silver plating layer 13 is easy to polish, has strong light reflection ability and good heat conduction, electrical conductivity and welding performance. The silver plating layer 13 is first applied to decoration, and is widely used in the electronic industry, communication configuration and instrument manufacturing industry to reduce the resistance of metal parts and improve the welding ability of metal. The plating layer is used to prevent corrosion, increase conductivity, reflectivity and aesthetics.

[0053] For example, when silver plating is carried out on copper or copper alloy parts, the parts must be degreased and rusted first, then pre-plated with thin silver or immersed in a solution composed of mercury chloride and other solutions for mercury treatment to form a layer of mercury film on the surface of the parts. Then, the parts are used as cathode and pure silver plate as anode, and are immersed in cyanide silver potassium electrolyte composed of silver nitrate and potassium cyanide for electroplating. The electroplating solution uses thiosulfate, sulfite, thiocyanate, ferrocyanide, etc. In order to prevent the silver plating layer from discoloring, post-plating treatment is usually required, mainly including immersion brightening, chemical and electrochemical passivation, plating of precious metals or rare metals or coating of cover layer, etc.

[0054] At the same time, by setting the substrate 1, the ASIC chip 3 and the MEMS chip 4 can be mounted and supported, and the bottom of the MEMS chip 4 and the ASIC chip 3 can be protected.

[0055] The top of the circuit board body 2 and away from the MEMS chip 4 side is provided with a PCB binding coil 5, the ASIC chip 3 is connected with a first copper wire 6, and the end of the first copper wire 6 away from the ASIC chip 3 is connected with the PCB binding coil 5.

[0056] The top of the substrate 1 is provided with a cover plate 7, the top of the cover plate 7 is provided with a through hole 8, and the bottom of the cover plate 7 is bonded with the top of the substrate 1 by glue. By setting the cover plate 7, the cover plate 7 can protect the MEMS chip 4 and the ASIC chip 3 on the top of the substrate 1.

[0057] The top of the ASIC chip 3 and the MEMS chip 4 is provided with a welding point 9, and the second copper wire 10 is arranged between the MEMS chip 4 and the ASIC chip 3. The two ends of the second copper wire 10 are connected with the top of the ASIC chip 3 and the MEMS chip 4 through the welding point 9 respectively. By setting the welding point 9, the second copper wire 10 is connected with the ASIC chip 3 and the MEMS chip 4.

[0058] The bottom of the ASIC chip 3 and the MEMS chip 4 around is coated with a glue layer 14, and the bottom of the ASIC chip 3 and the MEMS chip 4 is connected with the surface of the circuit board body 2 through the glue layer 14. By setting the glue layer 14, the glue layer 14 is used to fix the ASIC chip 3 and the MEMS chip 4 on the circuit board body 2. The glue layer 14 refers to the chip glue, which has good thermal conductivity, ensures that the logic route will not be burned out due to overheating, and can play the role of fixing, insulation, moisture-proof, filling, buffering and other protection of the chip. It has significant effect on prolonging the service life of the chip in the aspects of anti-falling, anti-mildew, anti-corrosion, anti-salt mist, anti-acid and alkali, anti-sulfurization, anti-aging, high and low temperature impact, high temperature and humidity resistance, etc. The chip glue is a cofferdam filling glue, which is a single-component epoxy glue suitable for IC packaging of epoxy glass substrate, such as battery circuit protection board and other products. The product has excellent solder resistance and moisture resistance, low thermal expansion coefficient to reduce deformation, excellent temperature cycle performance and better flowability. Cofferdam filling glue is an essential product for IC chip encapsulation and filling, which can be divided into cofferdam glue and filling glue. Cofferdam glue mainly dams the range that needs to be filled, effectively controls the flow and filling range of the filling glue. The filling glue can fully fill the cofferdam range, and after curing, it can play a good protective role for IC chips or electronic components.

[0059] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A novel silicon wafer packaging process, characterized in that: Includes the following steps: S1, ASIC and MEMS die mounting and curing: Apply ASIC fixing adhesive to the mounting positions of ASIC chips and MEMS chips on the PCB circuit board, and the die mounter head picks up the ASIC chips and MEMS chips and mounts them onto the PCB circuit board where the adhesive was applied. S2. Copper wire bonding connects the circuitry of the MEMS chip with the circuitry of the ASIC chip and the PCB chip via copper wires. S3. Apply silicone to the connection between the ASIC chip surface and the PCB gold wire to protect it; bake and cure the silicone at the connection between the ASIC chip surface and the PCB gold wire. S4. Applying solder paste: Applying solder paste to the PCB solder pads using a solder paste applicator. S5. Housing mounting and housing reflow soldering: The mounting head of the pick-and-place machine picks up the metal housing and mounts it onto the pads coated with solder paste; the solder paste is then reflowed and cured to fix the housing and protect the internal copper wires and chips of the product. S6. Marking: The product batch number is printed on the metal casing using a laser marking machine. S7, PCB separation and packaging: A water jet cutting machine is used to cut the entire PCB into individual products using a cutting blade. Then, a packaging machine is used to package and ship the individual products. The die-packing structure includes a substrate (1), a circuit board body (2) is embedded on the top of the substrate (1), an ASIC chip (3) is mounted on one side of the top of the circuit board body (2), a MEMS chip (4) is mounted on the other side of the top of the circuit board body (2), a PCB bonding coil (5) is provided on the top of the circuit board body (2) and on the side away from the MEMS chip (4), the ASIC chip (3) is connected to a first copper wire (6), and the end of the first copper wire (6) away from the ASIC chip (3) is connected to the PCB bonding coil (5).

2. The novel silicon wafer packaging process according to claim 1, characterized in that: A cover plate (7) is installed on the top of the substrate (1), and a through hole (8) is opened on the top of the cover plate (7). The bottom of the cover plate (7) is bonded to the top of the substrate (1) with glue.

3. The novel silicon wafer packaging process according to claim 2, characterized in that: The top of both the ASIC chip (3) and the MEMS chip (4) are provided with solder joints (9). A second copper wire (10) is provided between the MEMS chip (4) and the ASIC chip (3). Both ends of the second copper wire (10) are connected to the top of the ASIC chip (3) and the MEMS chip (4) respectively through solder joints (9).

4. The novel silicon wafer packaging process according to claim 3, characterized in that: The PCB wire bonding reel (5) includes a soldering reel (11) and a wire bonding reel (12). The soldering reel (11) is located on the top of the circuit board body (2), and the wire bonding reel (12) is located on the surface of one side of the circuit board body (2).

5. The novel silicon wafer packaging process according to claim 4, characterized in that: The top of the ASIC chip (3) is connected to the first copper wire (6) via solder joint (9), and the end of the first copper wire (6) away from the ASIC chip (3) is connected to the surface of the solder pad (11).

6. The novel silicon die-packing process according to claim 5, characterized in that: The surface of the welding pad (11) is coated with a silver plating layer (13), the thickness of which is 20-30 micrometers.

7. The novel silicon wafer packaging process according to claim 1, characterized in that: The bottom of both the ASIC chip (3) and the MEMS chip (4) is coated with an adhesive layer (14), and the bottom of the ASIC chip (3) and the MEMS chip (4) is connected to the surface of the circuit board body (2) through the adhesive layer (14).

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