PCB design method beneficial to FOB bonding stability

Abstract

The invention discloses a design method beneficial to FOB bonding stability. The design method comprises the following steps that S1, a flexible printed circuit (FPC) and a liquid crystal display (LCD) are in signal conduction, wherein a golden finger of the FPC and a golden finger of the LCD are in hot-pressing conduction through an ACF conductive particle layer; s2, signal conduction between the PCB and the FPC: copper plating of the PCB: firstly cleaning the hole wall of the drilling part of the PCB, then carrying out metallization processing on the drilling part of the PCB and generating a layer of copper with the required thickness, and then carrying out electrocoppering on the whole PCB, the drilling part of the printed circuit board PCB is conducted; and signal conduction: the golden fingers of the printed circuit board PCB and the golden fingers of the flexible circuit board FPC are conducted through hot pressing of the ACF conductive particle layer, the problem that the ACF conductive particle layer is not filled compactly is solved, the yield of the printed circuit board PCB and the flexible circuit board FPC through hot pressing of the ACF conductive particle layer is improved, and the conduction stability after bonding is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB design and production, and in particular to a PCB design method that is beneficial to FOB bonding stability. Background Art

[0002] Large-sized liquid crystal displays (LCDs) cannot do without the signal transmission of printed circuit boards (PCBs). The printed circuit board PCB needs to be connected to the liquid crystal display LCD, which is mainly accomplished by bonding the flexible circuit board (FPC) to the printed circuit board PCB. The conductive stability of the bonding is an important guarantee for functionality.

[0003] Moreover, after the PCB gold finger is bonded with the FPC through ACF, if bubbles are generated and the pressing is poor, the display screen will not light up. Specifically, the PCB and FPC signals are connected, and then the FPC and LCD signals are connected. Usually, the ACF conductive particle layer is blasted through hot pressing to connect the conductive gold fingers of the PCB and FPC, thereby achieving signal conduction. In this hot pressing process, if the ACF conductive particle layer fails to explode or the glue attached to the ACF cannot fill the gap between the PCB and FPC gold fingers, the signal conduction will not be achieved, thereby affecting the display effect of the LCD screen. Summary of the invention

[0004] The purpose of the present invention is to provide a PCB design method that is beneficial to the stability of FOB bonding, so as to solve the problems existing in the above-mentioned prior art, improve the problem of inaccurate filling of the ACF conductive particle layer, and improve the yield of the printed circuit board PCB and the flexible circuit board FPC through the hot pressing of the ACF conductive particle layer, thereby improving the conduction stability after bonding.

[0005] To achieve the above object, the present invention provides the following solution: The present invention provides a design method that is beneficial to the stability of FOB bonding, comprising the following steps:

[0006] S1, flexible circuit board FPC and liquid crystal display LCD signal conduction: the gold finger of the flexible circuit board FPC and the gold finger of the liquid crystal display LCD are connected by hot pressing through the ACF conductive particle layer;

[0007] S2, the printed circuit board PCB and the flexible circuit board FPC signal conduction:

[0008] Copper plating of printed circuit board (PCB): first clean the hole wall of the drilled part of the PCB, then metallize the drilled part of the PCB and generate a layer of copper of the required thickness, then electroplate copper on the entire PCB to make the drilled part of the PCB conductive;

[0009] Signal conduction: The gold fingers of the printed circuit board PCB and the gold fingers of the flexible circuit board FPC are connected by hot pressing through the ACF conductive particle layer.

[0010] Preferably, during the metallization treatment process of step S2, the drilled portion of the printed circuit board PCB is subjected to chemical deposition so that 0.508-1.02 micrometers of chemical copper is deposited on the hole wall of the drilled portion of the printed circuit board PCB.

[0011] Preferably, in the copper electroplating process of step S2, on the basis of depositing chemical copper on the hole wall of the drilled part of the printed circuit board PCB, the entire printed circuit board PCB is subjected to electrolytic reaction in a desired solution by the action of direct current, so that the board surface and the drilled part of the printed circuit board PCB are plated with copper.

[0012] Preferably, in step S2, before the gold fingers of the printed circuit board PCB and the gold fingers of the printed circuit board PCB are connected by hot pressing of the ACF conductive particle layer, the thickness of the ACF conductive particle layer is determined. The formula for determining the thickness of the ACF conductive particle layer is as follows:

[0013] T=(S1+S2) / 2*H / P+GAP+(S1'+S2') / 2*H' / P+α;

[0014] Among them, T is the thickness of the ACF conductive particle layer; H is the thickness of the gold finger of the flexible circuit board FPC; H' is the thickness of the gold finger of the printed circuit board PCB; GAP is 50%*ACF conductive particle diameter; α is 0.15~0.25*(H+H') / 2; S1 is the line spacing (lower spacing) on ​​the flexible circuit board FPC; S2 is the line spacing (upper spacing) on ​​the flexible circuit board FPC; S1' is the line spacing (lower spacing) on ​​the printed circuit board PCB; S2' is the line spacing (upper spacing) on ​​the printed circuit board PCB.

[0015] Preferably, in step S2, after the printed circuit board PCB is copper plated, a micro-etching treatment is performed on the printed circuit board PCB to remove oxides and contaminants on the copper-plated surface of the printed circuit board PCB.

[0016] Preferably, after the printed circuit board PCB is subjected to micro-etching treatment, the printed circuit board PCB is subjected to anti-oxidation treatment.

[0017] Preferably, the base copper thickness of the printed circuit board PCB is 12 um, and the total thickness after micro-etching, copper plating and anti-oxidation treatment is 31.5-44.5 um.

[0018] Preferably, in step S2, after determining the extreme difference of the copper plating of the gold fingers of the printed circuit board PCB, the length of the gold fingers of the printed circuit board PCB is determined, and the length of the gold fingers of the printed circuit board PCB is longer than the bow pressing width of the FOB bonding equipment.

[0019] Preferably, a silicone pad is placed on the bow of the FOB bonding equipment before pressing, and the silicone pad is attached under the bow and located above the printed circuit board PCB and the flexible circuit board FPC.

[0020] Preferably, the width of the bow strip is 2 mm, the thickness of the silicone skin is 0.2 mm, after the bow strip with the silicone skin is pressed down, the actual pressing width is 2.4 mm, and the length of the gold finger of the printed circuit board PCB is greater than or equal to 2.5 mm.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The present invention first conducts signals with a liquid crystal display LCD through a flexible circuit board FPC, and then conducts signals with a printed circuit board PCB and the flexible circuit board FPC. Specifically, a drilling portion of the printed circuit board PCB is first metallized to generate a copper layer of required thickness, and then the entire printed circuit board PCB is electroplated with copper. Then, the gold fingers of the printed circuit board PCB and the gold fingers of the flexible circuit board FPC are conducted through hot pressing of an ACF conductive particle layer, so as to improve the problem of inaccurate filling of the ACF conductive particle layer, improve the yield of the printed circuit board PCB and the flexible circuit board FPC through hot pressing of the ACF conductive particle layer, and further improve the conduction stability after bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 This is a schematic diagram of the structure of a flexible circuit board FPC in one embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a flexible circuit board FPC connected to a liquid crystal display LCD in one embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a printed circuit board PCB in one embodiment of the present invention;

[0027] Figure 4 It is a schematic diagram of a printed circuit board PCB connected to a flexible circuit board FPC in one embodiment of the present invention;

[0028] Figure 5 A schematic diagram of the design of the gold finger width of a printed circuit board PCB in one embodiment of the present invention;

[0029] Figure 6 A diagram showing a calculation formula for the thickness of the ACF conductive particle layer required for bonding in one embodiment of the present invention;

[0030] Figure 7 It is an enlarged view of the gold finger pressing gap of the printed circuit board PCB in one embodiment of the present invention;

[0031] Figure 8 A bubble diagram of gold finger bonding of a printed circuit board PCB in one embodiment of the present invention;

[0032] Fig. 9 This is a connection structure diagram of a liquid crystal display LCD product in one embodiment of the present invention;

[0033] Fig.10 It is a partial enlarged view of the gold finger of the printed circuit board PCB in the connection structure diagram of the liquid crystal display LCD product in one embodiment of the present invention;

[0034] Fig.11 This is a picture of an actual product without bubbles after bonding in one embodiment of the present invention;

[0035] Among them: 1-flexible circuit board FPC, 2-gold finger of flexible circuit board FPC, 3-liquid crystal display LCD, 4-gold finger of liquid crystal display LCD, 5-ACF conductive particle layer, 6-printed circuit board PCB, 7-gold finger of printed circuit board PCB, 8-silicone skin, 9-bow strip. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments 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 creative work are within the scope of protection of the present invention.

[0037] The purpose of the present invention is to provide a PCB design method that is beneficial to the stability of FOB bonding, so as to solve the problems existing in the above-mentioned prior art, improve the problem of inaccurate filling of the ACF conductive particle layer, and improve the yield of the printed circuit board PCB and the flexible circuit board FPC through the hot pressing of the ACF conductive particle layer, thereby improving the conduction stability after bonding.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] like Figures 1 to 11As shown, the production process of printed circuit board PCB6 is "cutting, inner layer, pressing, drilling, electroplating, outer layer, solder mask, gold plating (anti-oxidation treatment), text, molding, electrical testing, packaging, and transportation". The bonding and conduction of the gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC is related to the copper plating uniformity in the production process of printed circuit board PCB6. The copper electroplating step in the copper plating process plays a decisive role in the copper thickness uniformity of the printed circuit board PCB6.

[0040] This embodiment provides a design method that is beneficial to the stability of FOB bonding, including the following steps:

[0041] S1, signal conduction between the flexible circuit board FPC1 and the liquid crystal display LCD3: the gold finger 2 of the flexible circuit board FPC and the gold finger 4 of the liquid crystal display LCD are connected by hot pressing through the ACF conductive particle layer 5;

[0042] S2, the printed circuit board PCB6 and the flexible circuit board FPC1 signal conduction:

[0043] Copper plating of printed circuit board PCB6: first, the hole wall of the drilled part (resin and glass fiber of the non-conductive part) of the PCB printed circuit board PCB6 is cleaned. The specific cleaning work is: after the drilling work is completed, the hole wall is deburred and the glue residue is removed, and then the drilled part of the printed circuit board PCB6 is metallized and a layer of copper (PTH) of the required thickness is generated. Specifically, in the metallization process, the drilled part of the printed circuit board PCB6 is chemically deposited by chemical deposition, so that 0.508 to 1.02 microns of chemical copper are deposited on the hole wall of the drilled part of the printed circuit board PCB6, and then the entire printed circuit board PCB6 is electroplated with copper (DVCP) to make the drilled part of the printed circuit board PCB6 conductive. Specifically, on the basis of the deposition of chemical copper on the hole wall of the drilled part of the printed circuit board PCB6, the entire printed circuit board PCB6 is electrolytically reacted in the required solution by the action of direct current, so that the board surface and the drilled part of the printed circuit board PCB6 are plated with copper.

[0044] Among them, the working steps of metallizing the drilled part of the printed circuit board PCB6 and generating a layer of copper (PTH) of the required thickness include: board insertion, automatic board placement, sanding belt grinding, automatic grinding (1-3#), pressurized water washing, ultrasonic immersion, HFS water washing, WaterBlast (water spray), centering, bulking, water jet washing (1-4#), desmearing (1#2#), recycling water washing, water jet washing 5#, pre-neutralization, water jet washing (6#7#), neutralization, water jet washing (8-11#), inspection, hole filling, water jet washing (12-15#), micro-etching, pressurized water washing, water jet washing (16-19#), pre-impregnation, cremation, water jet washing (21-23#), reduction, water jet washing (24-27#), copper deposition (1-3#), water jet washing (28-31#), dry board assembly, cooling, automatic board collection, and board output.

[0045] The working steps of electroplating copper (DVCP) on the entire printed circuit board PCB6 include: automatic board placing machine, loading, degreasing, hot water washing, water washing after degreasing, pickling, front buffering, copper plating, rear buffering, water washing after electroplating, horizontal cleaning section, drying section, board unloading, and automatic board collecting machine.

[0046] Signal conduction: The gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC are connected by hot pressing through the ACF conductive particle layer 5. The present invention first conducts the signal with the liquid crystal display LCD3 through the flexible circuit board FPC1, and then conducts the signal with the printed circuit board PCB6 and the flexible circuit board FPC1. Specifically, the drilling part of the printed circuit board PCB6 is first metallized to generate a layer of copper of the required thickness, and then the entire printed circuit board PCB6 is electroplated with copper, and then the gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC are connected by hot pressing through the ACF conductive particle layer 5, so as to improve the problem of inaccurate filling of the ACF conductive particle layer, improve the yield of the printed circuit board PCB and the flexible circuit board FPC through the hot pressing of the ACF conductive particle layer, and then improve the conduction stability after bonding.

[0047] Preferably, in the process of metallizing the drilled part of the printed circuit board PCB6 and generating a layer of copper of the required thickness, the equipment that can be used includes but is not limited to the Cosmic horizontal copper deposition line, which is suitable for all products, and the Gantry copper deposition (vertical) can also be used, which is suitable for products with a board thickness of 0.6mm or more; in the process of electroplating copper on the entire printed circuit board PCB6, the equipment that can be used includes but is not limited to the Cosmic board wire, which is suitable for products except photovoltaic panels, light boards and line widths of less than 3mil, and the maximum difference in copper plating thickness on the same board is R≤10um, and the Dongwei line can also be used, which is suitable for all products, and the maximum difference in copper plating thickness on the same board is R≤6um.

[0048] Furthermore, hot pressing and conducting the gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC through the ACF conductive particle layer 5 is also related to the thickness of the ACF conductive particle layer 5. Therefore, in step S2, before hot pressing and conducting the gold finger 7 of the printed circuit board PCB and the gold finger 7 of the printed circuit board PCB through the ACF conductive particle layer 5, the thickness of the ACF conductive particle layer 5 is determined. The formula for determining the thickness of the ACF conductive particle layer 5 is as follows:

[0049] T=(S1+S2) / 2*H / P+GAP+(S1'+S2') / 2*H' / P+α;

[0050] Among them, T is the thickness of the ACF conductive particle layer 5; H is the thickness of the gold finger 2 of the flexible circuit board FPC; H' is the thickness of the gold finger 7 of the printed circuit board PCB; GAP is 50%*ACF conductive particle diameter; α is 0.15~0.25*(H+H') / 2; S1 is the line spacing (lower spacing) on ​​the flexible circuit board FPC1; S2 is the line spacing (upper spacing) on ​​the flexible circuit board FPC1; S1' is the line spacing (lower spacing) on ​​the printed circuit board PCB6; S2' is the line spacing (upper spacing) on ​​the printed circuit board PCB6.

[0051] Therefore, according to the formula for determining the thickness of the ACF conductive particle layer 5, it can be known that the thickness of the gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC both have an impact on the thickness of the ACF conductive particle layer 5. In order to make the ACF conductive particle layer 5 fill the gap between the gold finger 7 of the printed circuit board PCB and the gold finger 2 of the flexible circuit board FPC, the copper thickness range of the gold finger 7 of the printed circuit board PCB must be as small as possible, otherwise lamination bubbles will be generated, resulting in poor bonding. Therefore, it is necessary to select the corresponding equipment to make the copper plating range of the gold finger 7 of the printed circuit board PCB ≤6um.

[0052] Furthermore, in step S2, after the printed circuit board PCB6 is copper plated, the printed circuit board PCB6 is micro-etched to remove oxides and contaminants on the copper-plated surface of the printed circuit board PCB6. Preferably, after the printed circuit board PCB6 is micro-etched, the printed circuit board PCB6 is subjected to an anti-oxidation treatment. The steps of anti-oxidation treatment include: first, glue wrapping, in which adhesive tape is used to wrap the copper foil at the edge of the board to prevent gold from being deposited on the copper foil at the edge of the board, thereby saving the consumption of precious metals; second, pre-treatment, in which the surface of the printed circuit board PCB6 is cleaned of dirt and the copper surface is roughened; third, inserting the boards to be immerged in gold into the hanging basket in an orderly manner, and the hanging basket clamps the boards to prevent overlapping boards; fourth, gold deposition, in which a surface of palladium is adsorbed on the surface of the clean bare copper, a layer of nickel is deposited on the copper surface through the catalytic reaction of palladium, and then a layer of gold is generated on the nickel surface through the gold-nickel replacement reaction; fifth, glue tearing: the adhesive tape wrapped around the edge of the board is torn off and cleaned for post-processing and cleaning; sixth, post-processing, in which the surface of the printed circuit board PCB6 and the residual medicine in the hole are cleaned, and the surface of the printed circuit board PCB6 and the inside of the drilled part are baked.

[0053] Among them, the control method for anti-oxidation treatment of printed circuit board PCB6 includes: first, the micro-etching solution in the pre-treatment line contains acid, which can remove the oxidation problem of the copper surface before gold plating; pre-treatment sandblasting can also remove the oxidation of the copper surface before gold plating and the adhesion of organic matter; pre-treatment water washing, high-pressure water washing, and ultrasonic water washing can all clean the pollutants on the copper surface; second, during the production of gold-plated wire, there are also oil removal, micro-etching, and pickling tanks to remove oxidation and pollution on the gold surface; overflow water washing can also clean the pollution on the board surface; third, post-treatment pickling and water washing can remove pollutants on the gold surface; fourth, all personnel wear sulfur-free gloves during the entire production process.

[0054] Furthermore, the base copper thickness of the printed circuit board PCB6 is 12um, and the total thickness after micro-etching, copper plating and anti-oxidation treatment is 31.5 to 44.5um. Specifically, the typical value of the base copper thickness is 12um, and the range is 10um to 14um. During the micro-etching process, the range of thinning is -1um to -0.5um. During the copper plating process, the typical value of the copper plating thickness is 25, and the range is 20um to 25um. During the anti-oxidation treatment, the typical value of the nickel thickness is 2.5um to 6.5um, and the range is 2.5um to 6um, so that the total thickness is 31.5 to 44.5um. No bubbles are generated according to this design.

[0055] Further, in step S2, after determining the extreme copper plating of the gold finger 7 of the printed circuit board PCB, the length of the gold finger 7 of the printed circuit board PCB is determined. The length of the gold finger 7 of the printed circuit board PCB is longer than the pressing width of the bow bar 9 of the FOB bonding device. If the length of the gold finger 7 of the printed circuit board PCB is designed according to the length of the bow bar 9 or less than the length of the bow bar 9, the gold finger 7 of the printed circuit board PCB is completely covered by the pressure strip, and the bubbles cannot be discharged, resulting in bonding bubbles. Then, by improving the length of the gold finger 7 of the printed circuit board PCB, the length of the gold finger 7 of the printed circuit board PCB is equal to the pressing width of the bow bar 9 of the FOB bonding device, so that there is space for the bubbles to be discharged, and no bubbles are generated after bonding.

[0056] Among them, silicone skin 8 is placed on the bow strip 9 of the FOB bonding equipment before pressing. The silicone skin 8 is attached to the bottom of the bow strip 9 and is located above the printed circuit board PCB6 and the flexible circuit board FPC1. Placing the silicone skin 8 before pressing the bow strip 9 can buffer the temperature and ensure uniform temperature distribution, avoiding direct contact between the printed circuit board PCB6 and the flexible circuit board FPC1 and the bow strip 9. At the same time, the silicone skin 8 also has an isolation protection function to prevent static electricity leakage.

[0057] Preferably, the width of the bow strip 9 is 2 mm, the thickness of the silicone skin 8 is 0.2 mm, and after the bow strip 9 with the silicone skin 8 is pressed down, the actual pressing width is 2.4 mm, and the length of the gold finger 7 of the printed circuit board PCB is greater than or equal to 2.5 mm, so that there is space for bubbles to be discharged, and no bubbles are generated after bonding.

[0058] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0059] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0060] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A design method that is beneficial to the stability of FOB bonding, characterized in that: The steps include: S1, flexible circuit board FPC and liquid crystal display LCD signal conduction: the gold finger of the flexible circuit board FPC and the gold finger of the liquid crystal display LCD are connected by hot pressing through the ACF conductive particle layer; S2, Printed Circuit Board PCB and Flexible Circuit Board FPC signal conduction: Copper plating of printed circuit board (PCB): first clean the hole wall of the drilled part of the PCB, then metallize the drilled part of the PCB and generate a layer of copper of the required thickness, then electroplate copper on the entire PCB to make the drilled part of the PCB conductive; Signal conduction: The gold fingers of the printed circuit board PCB and the gold fingers of the flexible circuit board FPC are connected by hot pressing through the ACF conductive particle layer.

2. The design method for facilitating FOB bonding stability according to claim 1, characterized in that: During the metallization treatment process of step S2, chemical copper with a thickness of 0.508 to 1.02 microns is deposited on the hole wall of the drilled hole of the printed circuit board PCB by chemical deposition.

3. The design method for facilitating FOB bonding stability according to claim 2, characterized in that: In the copper electroplating process of step S2, on the basis of depositing chemical copper on the hole wall of the drilled part of the printed circuit board PCB, the entire printed circuit board PCB is subjected to electrolytic reaction in a desired solution through the action of direct current, so that the board surface and the drilled part of the printed circuit board PCB are plated with copper.

4. The design method for facilitating FOB bonding stability according to claim 3, characterized in that: In step S2, before the gold fingers of the printed circuit board PCB and the gold fingers of the printed circuit board PCB are connected through the ACF conductive particle layer by hot pressing, the thickness of the ACF conductive particle layer is determined. The formula for determining the thickness of the ACF conductive particle layer is as follows: T=(S1+S2) / 2*H / P+GAP+(S1'+S2') / 2*H' / P+α; Among them, T is the thickness of the ACF conductive particle layer; H is the thickness of the gold finger of the flexible circuit board FPC; H' is the thickness of the gold finger of the printed circuit board PCB; GAP is 50%*ACF conductive particle diameter; α is 0.15~0.25*(H+H') / 2; S1 is the line spacing (lower spacing) on ​​the flexible circuit board FPC; S2 is the line spacing (upper spacing) on ​​the flexible circuit board FPC; S1' is the line spacing (lower spacing) on ​​the printed circuit board PCB; S2' is the line spacing (upper spacing) on ​​the printed circuit board PCB.

5. The design method for facilitating FOB bonding stability according to claim 4, characterized in that: In step S2, after the printed circuit board PCB is copper plated, a micro-etching process is performed on the printed circuit board PCB to remove oxides and contaminants on the copper plated surface of the printed circuit board PCB.

6. The design method for facilitating FOB bonding stability according to claim 5, characterized in that: After the printed circuit board PCB is subjected to micro-etching treatment, the printed circuit board PCB is subjected to anti-oxidation treatment.

7. The design method for facilitating FOB bonding stability according to claim 6, characterized in that: The base copper thickness of the printed circuit board PCB is 12um, and the total thickness is 31.5~44.5um after micro-etching, copper plating and anti-oxidation treatment.

8. The design method for facilitating FOB bonding stability according to claim 7, characterized in that: In step S2, after determining the extreme difference of the copper plating of the gold finger of the printed circuit board PCB, the length of the gold finger of the printed circuit board PCB is determined, and the length of the gold finger of the printed circuit board PCB is longer than the bow pressing width of the FOB bonding equipment.

9. The design method for facilitating FOB bonding stability according to claim 8, characterized in that: Silicone pads are placed on the bow strips of the FOB bonding equipment before pressing. The silicone pads are attached to the bottom of the bow strips and are located above the printed circuit board PCB and the flexible circuit board FPC.

10. The design method for facilitating FOB bonding stability according to claim 9, characterized in that: The width of the bow strip is 2mm, the thickness of the silicone skin is 0.2mm, after the bow strip with the silicone skin is pressed down, the actual pressing width is 2.4mm, and the length of the gold finger of the printed circuit board PCB is greater than or equal to 2.5mm.

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