Special chip microphone tube with special lead-out mode for DNF packaging

Abstract

The utility model relates to a special chip microphone tube with a special lead-out mode for DNF packaging, which comprises a metal frame, a microphone special chip and a rectangular plastic package body, and is characterized in that the microphone special chip is positioned above the front surface of the metal frame, and the bottom of the microphone special chip is adhered to a grid special position in the middle of the surface of the metal frame by conductive adhesive; drain electrode pressure points and source electrode pressure points on the front surface of the chip are arranged on the drain electrode special positions and the source electrode special positions on the two sides of the front surface of the metal frame through metal connecting wires, and three leading-out ends of a drain electrode, a grid electrode and a source electrode are formed on the back surface of the frame from left to right; and the microphone special chip and the metal connecting wire thereof are sealed in the plastic package body. The utility model has the advantages that: a new structural mode and a new process are utilized, and the packaging structure has the characteristics of low packaging cost, good compactness of packaged products and wide application range.

Description

Technical Field

[0001] The utility model relates to a patch microphone tube with a special DNF packaging and a unique lead-out method; hereinafter referred to as the DNF patch microphone tube. Background Art

[0002] The DNF semiconductor packaging process has been widely used in the packaging of diodes and triodes. It has the advantages of low packaging cost, good compactness of the packaged finished products, and wide application range. Among them, the general cuboid style adopts a lead-out structure on both sides of the pins. For the diode, the positive and negative electrodes are exactly set at the left and right ends; for the triode, the base or grid is set at one end, and the emitter and collector, or drain and source are set at the other end; the three electrodes are separated by a "T"-shaped plastic cover. The horizontal bar separates the base or grid from the other two electrodes at the other end, and the vertical bar separates the emitter and collector, or the drain and source.

[0003] At present, there are various packaging styles for the field-effect transistors used in electret microphones. For such microphone tubes used in micro-miniature microphone amplifiers with a size of less than 6 mm, the main style is the patch component tape and reel style. The patch die uses the traditional strip-shaped three-terminal frame: the chip (the back is the grid) is pasted in the middle of the frame, and then the metal leads after hot melting and fixing at the two drain and source pressure points are respectively connected and positioned with the two ends of the frame to form three pins of the grid, drain, and source. After the die is encapsulated, the frame must be punched and formed so that the pins on it are bent and scattered according to the rules, and then through testing and taping, the qualified transistors can be formed. Summary of the Invention

[0004] The purpose of the utility model is to overcome the above problems existing in the prior art, and provide a patch microphone tube with a special DNF packaging and a unique lead-out method. The utility model designs a patch microphone tube with a special DNF packaging and a unique lead-out method, including a metal frame 1, a microphone special chip 12, and a rectangular plastic package 9. It is characterized in that: the microphone special chip is located above the front of the metal frame, and its bottom is bonded to the grid special position 3 in the middle of the metal frame surface with conductive adhesive. The drain 6 and source 8 pressure points on the front of the chip are connected to the drain 2 and source special positions 4 on both sides of the front of the metal frame through metal wires, and three lead-out ends of the drain 6, grid 7, and source 8 are formed from left to right on the back of the frame. The front of the metal frame is covered with silicone or epoxy resin by a molding method to form the plastic package 9. The microphone special chip and its metal wires are all enclosed in the plastic package 9. The height of the plastic package is limited to less than 0.4 mm. The metal frame 1 is provided with a hollow 5 between the drain 6, grid 7, and source 8.

[0005] The utility model introduces the DFN packaging process for the manufacture of microphone-specific tubes for the first time: according to this process, thousands of microphone-specific chips are bonded to the gate terminals of each monomer on the whole metal frame one by one, and then the connection lines are drawn from the drain and source pressure points on the front of the chip to the output terminal (drain) and the ground terminal (source) of the frame monomer respectively. After the bonding and wire bonding of all single chips on the frame are completed, the DNF mold is used for high-pressure plastic sealing to form a combination consisting of thousands of single microphone tube cores on the whole frame; then the combination is divided into several semi-finished monomers according to the rules by cutting. Although the monomer semi-finished products still need to undergo the same test tape as the original manufacturing process, the frame punching and pin bending are omitted, and the extremely high-precision rib cutting mold and the more complicated pin bending operation are no longer required. The injection molding plastic and frame alloy materials consumed by the product are only 1 / 5 of the original process, which greatly reduces the manufacturing cost.

[0006] The DNF patch microphone tube designed by the utility model has a tube body with a length and width of only 1.2X0.8mm. In addition to the output terminal (drain) and the ground terminal (source) on the surface, there is also a gate terminal that is bonded to the chip and led out. In a very small area, if the three lead-out terminals are distributed in the rectangular style of the general DNF, with the gate positioned on one side and the drain and source positioned in half on the other side, the drain and source electrodes will inevitably be made thin and short, and the plastic sealing part separating them in the middle will also be very narrow, which will greatly increase the difficulty of patching, reduce the processing qualification rate of the subsequent process, and may even cause the three-terminal pins to be interconnected due to the flow of solder paste during patching.

[0007] The utility model is characterized in that: the three pins of the drain, gate and source of the tube core are arranged in sequence from left to right, which is completely different from the pin distribution method on both sides of the general DNF package; and a color point identification mark is set; its thickness is also limited by the height of the electret microphone matched therewith, which is different from the 0.5mm limit size of the general package. On the basis of the improvement of the mold design and the frame structure, the product thickness is controlled to be 0.4mm or less.

[0008] To manufacture this kind of utility model DNF patch microphone tube, only a specially designed frame structure can be used, which is obviously different from the general DNF transistor frame. It is characterized in that the frame is composed of thousands of tube core monomer positions; each monomer includes a three-terminal metal sheet of drain, gate and source and a hollow area around it, leaving only six thin wires to connect the head and tail of each metal sheet in pairs, and penetrate the adjacent monomers to form a complete large metal frame; cutting gaps are left between each monomer in the frame. As mentioned above, after the DNF mold high-pressure plastic sealing, the tube core assembly is formed on the whole frame, which is placed in a special cutting machine, and the gaps between the monomers on the frame are regularly cut in the X and Y directions to obtain scattered semi-finished monomers.

[0009] The advantages of the present utility model are as follows: By using a new structural method and a new process, it has the characteristics of low packaging cost, good compactness of the packaged product, and wide applicability. Description of the Drawings

[0010] Appendix Figure 1 It is a schematic diagram of the structure of the DNF patch microphone tube of the present utility model and its thickness control.

[0011] Appendix Figure 2 It is a schematic diagram of the arrangement of the three-terminal pins on the lead-out surface of the DNF patch microphone tube of the present utility model.

[0012] Appendix Figure 3 It is a schematic diagram of a single die encapsulation position in the frame for manufacturing the DNF patch microphone tube of the present utility model. Detailed Embodiment

[0013] In the figure, a patch microphone tube with a special lead-out method for DNF packaging includes a metal frame 1, a microphone-specific chip 12, and a rectangular plastic package 9. It is characterized in that: the microphone-specific chip is located above the front of the metal frame, and its bottom is bonded to the gate-specific position 3 in the middle of the metal frame surface with conductive adhesive. The drain 6 and source 8 pressure points on the front of the chip are connected to the drain 2 and source-specific position 4 on both sides of the front of the metal frame through metal wires. On the reverse side of the frame, three lead-out terminals, namely the drain 6, gate 7, and source 8, are formed from left to right. The front of the metal frame is covered with silicone or epoxy resin by a molding method to form the plastic package 9. The microphone-specific chip and its metal wires are all enclosed in the plastic package 9. The height of the plastic package is limited to less than 0.4 mm. A hollow 5 is provided between the drain 6, gate 7, and source 8 of the metal frame 1.

[0014] For a patch microphone tube with a special lead-out method for DNF packaging, the area around the three lead-out terminal metal sheets is a hollow area 5, and only six thin lines 10 are left to connect the head and tail of each metal sheet in pairs respectively and communicate with adjacent monomers, forming a complete large metal frame 1; there are cutting gaps 11 between the monomers in the frame; after the chip bonding and wire bonding of all single chips on the frame are completed, through high-pressure plastic encapsulation with a DNF mold, a combination body composed of thousands of single microphone tube cores is formed on the entire frame ( Figure 3 of a single frame closely arranged in an array); then, through cutting, the combination body is divided into several semi-product monomers according to rules, and the monomers are tested and taped, that is, the finished product of the DNF microphone special tube in the form of a taped reel is formed. The appearance size of a single finished product is 1.2X0.8X0.4mm; on the lead-out surface, the three-terminal metal pins are the gate 3 (G), drain 2 (D), and source 4 (S) from left to right in sequence; there is a plastic-covered surface separating the periphery and between the three terminals.

[0015] During production, 1. When designing the special mold, the outer dimensions of the entire metal frame are determined. The frame is a large rectangular metal sheet composed of the positions of thousands of regularly arranged die monomers. The shape of the monomer positions within the frame is as shown in the appendix Figure 3 as follows;

[0016] 2. Using the DFN semiconductor packaging process, die bonding and wire bonding operations are successively performed on the frame, so that each monomer is bonded with a chip, and after die bonding and wire bonding, the three terminals of the gate (G), drain (D), and source (S) are led out;

[0017] 3. Use a special plastic encapsulation mold to inject silicone or epoxy resin into the entire frame with chips inside under high pressure;

[0018] 4. After injection molding, cut the combined body in which the plastic encapsulated plane and the entire frame are integrated, and then send the cut single semi-finished product to a special test and taping machine for test and taping, and a surface mount microphone tube with a unique lead-out method of DNF can be obtained.

Claims

1. A patch microphone tube with a special DNF encapsulation and a unique lead-out method, comprising a metal frame (1), a dedicated microphone chip (12), and a rectangular plastic package (9), characterized in that: The dedicated microphone chip is located above the front of the metal frame, and its bottom is bonded to the dedicated gate position (3) in the middle of the metal frame surface with conductive adhesive. The drain (6) and source (8) pressure points on the front of the chip are connected to the dedicated drain (2) and source positions (4) on both sides of the front of the metal frame through metal wires. On the back of the frame, three lead-out terminals of drain (6), gate (7), and source (8) are formed from left to right. The front of the metal frame is covered with silicone or epoxy resin by molding to form a plastic package (9), and the dedicated microphone chip and its metal wires are all enclosed in the plastic package (9).

2. The patch microphone tube with a dedicated DNF packaging specific lead-out method according to claim 1, characterized in that: The height of the plastic package is limited to less than 0.4 mm.

3. A patch microphone tube with a dedicated DNF encapsulation and a specific lead-out method, characterized in that: The metal frame (1) is provided with a hollow (5) between the drain (6), gate (7), and source (8).

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