Optical fingerprint module chip gold thread binding structure

Abstract

The utility model discloses an optical fingerprint module chip gold thread binding structure, which comprises a substrate and a lens carried on the substrate, a chip is bound on the substrate, the lens is carried right above the chip, a gold thread used for binding is arranged between the chip and the substrate, a metal PAD is arranged on the chip, and the metal PAD is arranged on the substrate. The gold thread is located between the metal PAD and the substrate, the size of the metal PAD is smaller than or equal to 60 microns, and the diameter of the gold thread is 0.7 mil. According to the utility model, a proper gold wire is selected to bind the small-size metal PAD and the substrate, so that the chip is electrically connected with the substrate, and the module assembly effect is not affected.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fingerprint modules, in particular to a gold wire binding structure of an optical fingerprint module chip. Background Art

[0002] The optical fingerprint module is composed of components such as capacitors, chips, connectors, flexible circuit boards, lens + holder integrated materials and other main parts. All materials are completed through SMT / COB hardware assembly and functional testing. Then the flexible circuit board completes the mounting of capacitors, connectors and other materials in SMT, and the gold wire binding, IR sheet attachment and lens mounting of the chip are carried out in COB. With the further development and widespread application of optical fingerprint recognition methods, the optical fingerprint module is developing towards ultra-thin, the external dimensions are getting smaller and smaller, and the internal chip size is also improving towards a small size solution. Then the pad size of the optical fingerprint chip of the COB process solution is reduced from the conventional 100um to 40um, and the spacing between adjacent pads is also reduced synchronously. At the same time, the original single-row gold wire is now double-row gold wire, which brings great challenges to the production process. Due to the smaller PAD size of the chip, it is impossible to complete the binding according to the conventional 0.8mil gold wire. The chip pad has the problem of being unable to implant gold balls or there is a short circuit between adjacent pads, which affects the assembly. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies in the prior art and provide a gold wire binding structure for an optical fingerprint module chip.

[0004] The purpose of this utility model is achieved through the following technical solutions:

[0005] A gold wire binding structure for an optical fingerprint module chip, comprising: a substrate and a lens mounted on the substrate, a chip bound to the substrate, the lens mounted directly above the chip, a gold wire for binding arranged between the chip and the substrate, a metal PAD arranged on the chip, the gold wire located between the metal PAD and the substrate, the size of the metal PAD ≤ 60 um, and the diameter of the gold wire is 0.7 mil.

[0006] In one embodiment, the substrate is an FPC or a PCB board.

[0007] In one embodiment, a gold ball is implanted at one end of the gold wire close to the metal PAD, the gold ball contacts the metal PAD, and the end of the gold wire close to the metal PAD is fixedly connected to the metal PAD through the gold ball.

[0008] In one embodiment, the diameter of the gold ball is 43um-48um, and the thrust of the gold ball is ≥9g.f.

[0009] In one embodiment, the other end of the gold wire is fixed on the substrate, a gold finger is provided on the substrate, and one end of the gold wire away from the metal PAD is fixed on the gold finger of the substrate.

[0010] In one embodiment, the gold wire is a bridge for connecting the metal PAD with the substrate to build a circuit, and the chip is electrically connected to the substrate.

[0011] In one embodiment, the gold wire is fixed by one of thermal ultrasonic / gold wire ball bonding, ultrasonic wedge bonding, hot pressure bonding, and thermoacoustic bonding, and the gold wire is bonded by spherical bonding or hot pressure wedge bonding.

[0012] In one embodiment, the diameter of the welding point between the gold wire and the gold finger of the substrate is 2-3 times the diameter of the gold wire.

[0013] In one embodiment, a filter is attached above the chip, the filter is located directly below the lens, and the thickness of the filter is about 0.2 mm.

[0014] In one embodiment, a reinforcing plate is provided on a side of the substrate away from the chip, and the thickness of the reinforcing plate is 0.2 mm.

[0015] Compared with the prior art, the utility model has at least the following advantages:

[0016] The utility model discloses a gold wire binding structure for an optical fingerprint module chip, which connects a metal PAD of the chip with a substrate by setting a gold wire of a suitable diameter, so that the gold wire completes the binding of the chip with the substrate, thereby not affecting the assembly of the optical fingerprint module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments are briefly introduced below.

[0018] Figure 1 A schematic diagram of the structure of a gold wire binding structure of an optical fingerprint module chip provided by the utility model;

[0019] Figure 2 A schematic diagram of the structure of an optical fingerprint module chip gold wire binding structure without a lens provided by the utility model;

[0020] Figure 3 A schematic diagram of the structure of the chip and the substrate binding in the gold wire binding structure of an optical fingerprint module chip provided by the utility model;

[0021] Figure 4A side structural schematic diagram of a gold wire binding structure of an optical fingerprint module chip provided by the utility model.

[0022] Description of the drawings: 10, substrate; 20, lens; 30, chip; 31, metal PAD; 40, gold wire; 50, gold ball; 60, filter; 70, capacitor; 80, connector; 90, reinforcement plate. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings.

[0024] An optical fingerprint module chip gold wire binding structure, referring to Figure 1 , including a substrate 10 and a lens 20 mounted on the substrate 10 , a chip 30 is bound to the substrate 10 , and the lens 20 is mounted directly above the chip 30 .

[0025] Further, refer to Figure 1 , the substrate 10 is a FPC or a PCB board.

[0026] Reference Figure 2 and Figure 3 A gold wire 40 for binding is provided between the chip 30 and the substrate 10, wherein a metal PAD 31 is provided on the chip 30, the metal PAD 31 is made of metal material, and the gold wire 40 is located between the metal PAD 31 and the substrate 10. The size of the metal PAD 31 is ≤60um, so the diameter of the gold wire 40 in this embodiment is 0.7mil, and the diameter of the porcelain nozzle for punching the gold wire 40 is selected to be ≤60um.

[0027] Reference Figure 2 and Figure 3 A gold ball 50 is implanted at one end of the gold wire 40 close to the metal PAD 31, and the gold ball 50 directly contacts the aluminum pad of the metal PAD 31, so that the end of the gold wire 40 close to the metal PAD 31 is fixedly connected to the metal PAD 31. The diameter of the gold ball 50 is 43um-48um, and the thrust of the gold ball 50 is ≥9g.f.

[0028] Reference Figure 2 and Figure 3 The other end of the gold wire 40 is fixed on the substrate 10, and a gold finger is provided on the substrate 10. The end of the gold wire 40 away from the metal PAD 31 is fixed on the gold finger of the substrate 10. The gold wire 40 is a bridge for the metal PAD 31 and the substrate 10 to build a circuit connection. After the bonding is completed, the metal PAD 31 and the substrate 10 are connected in circuit, and the electrical signal on the chip 30 can be transmitted to the substrate 10.

[0029] Further, refer to Figure 2 and Figure 3The fixing method of the gold wire 40 is one of thermal ultrasonic / gold wire ball bonding, ultrasonic wedge bonding, hot pressure bonding, and thermoacoustic bonding, and the bonding method of the gold wire 40 and the substrate 10 is ball bonding or hot pressure wedge bonding.

[0030] Further, refer to Figure 2 and Figure 3 The diameter of the welding point between the gold wire 40 and the gold finger of the substrate 10 is 2-3 times the diameter of the gold wire 40.

[0031] Reference Figure 4 A filter 60 is disposed above the chip 30, and the filter 60 is attached to the upper surface of the chip 30 by glue, and the filter 60 is located directly below the lens 20. The bright side of the filter 60 faces the lens 20, and the dark side of the filter 60 faces the chip 30. The thickness of the filter 60 is about 0.2 mm.

[0032] Reference Figure 2 A plurality of capacitors 70 are also disposed on the substrate 10 , and the plurality of capacitors 70 are all fixed on the substrate 10 by means of SMT.

[0033] Reference Figure 2 A connector 80 is provided at one end of the substrate 10 away from the lens 20 , and the connector 80 is used to connect to the customer's mainboard to ensure the normal use of the lens 20 .

[0034] Reference Figure 4 A reinforcing plate 90 is provided on the side of the substrate 10 away from the chip 30. The reinforcing plate 90 is used to provide hardness support for the substrate 10 so that the substrate 10 at the chip 30 has a certain hardness. The reinforcing plate 90 is a steel sheet with a thickness of 0.2 mm. The reinforcing plate 90 is attached to the back of the substrate 10 by conductive adhesive, and the outer edge of the reinforcing plate 90 does not exceed the outer edge of the substrate 10.

[0035] Reference Figure 3 , by selecting a gold wire 40 of a suitable diameter to connect the metal PAD 31 of the chip 30 and the substrate 10, so that the gold wire 40 completes the binding of the chip 30 and the substrate 10, thereby not affecting the assembly of the optical fingerprint module.

[0036] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. An optical fingerprint module chip gold wire binding structure, characterized in that: include: A substrate (10) and a lens (20) mounted on the substrate (10); a chip (30) is bound to the substrate (10); the lens (20) is mounted directly above the chip (30); a gold wire (40) for binding is provided between the chip (30) and the substrate (10); a metal PAD (31) is provided on the chip (30); the gold wire (40) is located between the metal PAD (31) and the substrate (10); the size of the metal PAD (31) is ≤60um; and the diameter of the gold wire (40) is 0.7mil.

2. The gold wire binding structure of an optical fingerprint module chip according to claim 1, characterized in that: The substrate (10) is an FPC or a PCB board.

3. The gold wire binding structure of an optical fingerprint module chip according to claim 1, characterized in that: A gold ball (50) is implanted at one end of the gold wire (40) close to the metal PAD (31), the gold ball (50) is in contact with the metal PAD (31), and the end of the gold wire (40) close to the metal PAD (31) is fixedly connected to the metal PAD (31) via the gold ball (50).

4. The gold wire binding structure of an optical fingerprint module chip according to claim 3, characterized in that: The diameter of the gold ball (50) is 43um-48um, and the thrust of the gold ball (50) is ≥9g.f.

5. The gold wire binding structure of an optical fingerprint module chip according to claim 4, characterized in that: The other end of the gold wire (40) is fixed on the substrate (10), a gold finger is provided on the substrate (10), and one end of the gold wire (40) away from the metal PAD (31) is fixed on the gold finger of the substrate (10).

6. The gold wire binding structure of an optical fingerprint module chip according to claim 5, characterized in that: The gold wire (40) serves as a bridge for establishing a circuit connection between the metal PAD (31) and the substrate (10), and the chip (30) is electrically connected to the substrate (10).

7. The gold wire binding structure of an optical fingerprint module chip according to claim 6, characterized in that: The fixing method of the gold wire (40) is one of thermal ultrasonic / gold wire ball bonding, ultrasonic wedge bonding, hot pressure bonding, and thermoacoustic bonding, and the bonding method of the gold wire (40) is ball bonding or hot pressure wedge bonding.

8. The gold wire binding structure of an optical fingerprint module chip according to claim 6, characterized in that: The diameter of the welding point between the gold wire (40) and the gold finger of the substrate (10) is 2 to 3 times the diameter of the gold wire (40).

9. The gold wire binding structure of an optical fingerprint module chip according to claim 1, characterized in that: A filter (60) is attached above the chip (30), the filter (60) is located directly below the lens (20), and the thickness of the filter (60) is approximately 0.2 mm.

10. The gold wire binding structure of an optical fingerprint module chip according to claim 1, characterized in that: A reinforcing plate (90) is provided on a side of the substrate (10) away from the chip (30), and the thickness of the reinforcing plate (90) is 0.2 mm.

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