Method for manufacturing gold electroplated circuit board surface

Abstract

The present invention provides a method for electroplating gold on the surface of a circuit board. The method comprises the following steps: (1) first printing ink on the surface of the circuit board to form an ink layer; (2) slotting the ink layer to form grooves; (3) second printing a conductive silver paste in the grooves and curing the paste, then grinding the circuit board to remove the ink; and (4) electroplating the circuit board after the ink is removed with gold, and then removing the conductive silver paste. The method can effectively solve problems such as residual conductive wires or gaps in the gold plating pattern that occur during the gold plating process for drawing conductive wires, and does not require etching, thereby reducing costs and improving efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor testing, and in particular relates to a method for manufacturing gold electroplated on the surface of a circuit board. Background Art

[0002] In the semiconductor testing field, probe cards used for wafer inspection and load boards for final chip testing require repeated contact with the tester's probes. Therefore, the corresponding pads (PADs) on the printed circuit board (PCB) require gold plating to extend their lifespan. Due to product design, the pattern requiring gold plating often accounts for more than 50% of the total pattern and is distributed across the entire board surface, making it impossible to use gold plating processes for gold fingers on the board edges.

[0003] Currently, the commonly used electroplating gold process is to first make electroplated gold, then use the electroplated gold layer as an anti-etching layer, and then perform alkaline etching. However, due to the characteristics of etching, the side will be etched away while etching downwards, resulting in the phenomenon of hanging gold. If the hanging gold falls, it will cause a short circuit. If the hanging gold collapses, it will cause PAD defects.

[0004] In response to the problem of hanging gold in the existing technology, the conventional solution is the conductive wire electroplating gold process. The principle is to design the conductive wire in advance, connect the pattern that needs to be electroplated with gold with the plate frame to form a conductive path, etch out the pattern with the conductive wire during etching, and then cover the conductive wire with dry film protection, and then electroplate gold. In this way, the pattern that needs to be electroplated with gold will be plated with gold, and the conductive wire will not be plated with gold. The dry film is then removed and alkaline etching is performed. At this time, the conductive wire will be etched away because there is no electroplated gold protection, leaving only the required electroplated gold pattern.

[0005] Although the conductive wire electroplating gold process can solve the problem of suspended gold, there will be alignment deviations due to the dry film protection covering the conductive wire, resulting in incomplete or excessive dry film coverage of the conductive wire, residual conductive wires or gaps in the electroplated gold pattern, which affect the appearance and product quality.

[0006] In summary, there is an urgent need to develop a method for producing a fully enclosed pattern of electroplated gold to solve the problem of conductive wire residue or electroplated gold pattern gaps caused by the use of the conductive wire pulling electroplating process. Summary of the Invention

[0007] The object of the present invention is to provide a method for manufacturing gold plating on the surface of a circuit board. The method can effectively solve the problems of conductive wire residue or gold plating pattern gaps in the conductive wire electroplating process, and does not require etching treatment, thereby reducing costs and improving efficiency.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for manufacturing gold electroplated on the surface of a circuit board, the method comprising the following steps:

[0010] (1) performing a first printing ink on the surface of the circuit board to form an ink layer;

[0011] (2) grooving the ink layer to form grooves;

[0012] (3) printing a second conductive silver paste in the groove and curing the paste, and then grinding the circuit board to remove the ink;

[0013] (4) Electroplating the circuit board after removing the ink with gold, and then removing the conductive silver paste.

[0014] In the present invention, the manufacturing method is used to perform full-surround electroplating of gold on patterns on a circuit board. The conductive silver paste (commercially available) is a conductive silver paste that can be cured at high temperature and has the characteristics of high hardness and good conductivity after curing.

[0015] The present invention realizes the process steps of the conductive path required for gold electroplating by cutting grooves on the ink layer and then printing conductive silver paste in the grooves, without the need to pull conductive wires, thereby solving the problems of residual conductive wires or gaps in the gold electroplating pattern existing in the prior art.

[0016] It is worth noting that the conductive silver paste will not be plated with gold, so no additional etching is required, and there is no pattern transfer process in the process flow, so there is no pattern alignment; in addition, the conductive path formed by the conductive silver paste is more stable than that formed by pulling conductive wires.

[0017] As a preferred technical solution of the present invention, step (1) before the first printing further includes: pre-processing the circuit board.

[0018] Preferably, the pretreatment includes sequentially performing material discharging, inner layer forming, lamination, drilling, electroplating and etching to form a circuit board with patterns.

[0019] In the present invention, the operation methods of each pre-treatment step are not specifically limited and can be adjusted by those skilled in the art according to actual conditions. The pattern on the circuit board meets customer requirements and no additional components (such as conductive wires) or other components are added to provide gold plating paths.

[0020] As a preferred technical solution of the present invention, the viscosity of the ink in step (1) is 60-180 mPa.s, for example, it can be 70 mPa.s, 80 mPa.s, 90 mPa.s, 100 mPa.s, 110 mPa.s, 120 mPa.s, 140 mPa.s, 150 mPa.s or 170 mPa.s, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0021] In the present invention, the ink is solidified under specific conditions and has a high hardness after solidification. The solidified ink can be removed under another specific condition.

[0022] Preferably, during the first printing in step (1), the mesh size of the screen is 250-350 mesh, for example, it can be 260 mesh, 270 mesh, 280 mesh, 290 mesh, 300 mesh, 310 mesh, 320 mesh, 330 mesh or 340 mesh, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0023] Preferably, during the first printing in step (1), the pressure of the scraper is 20-30kgf, for example, it can be 21kgf, 22kgf, 23kgf, 24kgf, 25kgf, 26kgf, 27kgf, 28kgf or 29kgf, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0024] Preferably, during the first printing in step (1), the angle of the scraper is 60-80°, for example, it can be 62°, 65°, 67°, 70°, 72°, 75°, 77° or 79°, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0025] Preferably, the speed of the first printing in step (1) is 0.2-0.3 m / s, for example, it can be 0.21 m / s, 0.22 m / s, 0.23 m / s, 0.24 m / s, 0.25 m / s, 0.26 m / s, 0.28 m / s or 0.29 m / s, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0026] Preferably, after the first printing in step (1), the process further includes sequentially performing first baking, exposure, development and second baking.

[0027] In the present invention, the exposure energy is 2000-3000 mj, for example, it can be 2100 mj, 2300 mj, 2500 mj, 2600 mj, 2800 mj or 2900 mj, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0028] In the present invention, the conditions and parameters for curing the ink, such as the first baking, development, and second baking, are not specifically limited. Their function in the present invention is to cure the ink. Those skilled in the art can adjust the parameters of the above operations according to actual conditions.

[0029] As a preferred technical solution of the present invention, the grooving method in step (2) includes laser grooving.

[0030] In the present invention, the laser used in the laser grooving includes a five-element mixed gas laser or a UV laser.

[0031] Preferably, the depth of the groove in step (2) is the height of the ink layer.

[0032] Preferably, the width of the groove in step (2) is 5-10 mil, for example, it can be 5.5 mil, 6 mil, 6.5 mil, 7 mil, 7.5 mil, 8 mil, 8.5 mil, 9 mil or 9.5 mil, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, in step (3), during the second printing, the mesh size of the screen is 300-500 mesh, for example, it can be 320 mesh, 340 mesh, 350 mesh, 370 mesh, 400 mesh, 420 mesh, 440 mesh, 450 mesh, 470 mesh or 490 mesh, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0034] Preferably, during the second printing in step (3), the pressure of the scraper is 10-60kgf, for example, it can be 15kgf, 20kgf, 25kgf, 30kgf, 35kgf, 40kgf, 45kgf, 50kgf or 55kgf, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0035] Preferably, during the second printing in step (3), the angle of the scraper is 10-20°, for example, it can be 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18° or 19°, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0036] Preferably, the speed of the second printing in step (3) is 0.2-0.6 m / s, for example, it can be 0.25 m / s, 0.3 m / s, 0.35 m / s, 0.4 m / s, 0.45 m / s, 0.5 m / s or 0.55 m / s, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the curing in step (3) includes a first temperature increase and a second temperature increase performed sequentially.

[0038] In the present invention, one end of the solidified conductive silver paste is connected to the pattern to be electroplated with gold, and the other end is connected to the plate frame to provide a path for electroplating gold.

[0039] Preferably, the endpoint temperature of the first heating is 140-160°C, for example, it can be 142°C, 144°C, 145°C, 146°C, 148°C, 150°C, 152°C, 154°C, 155°C, 157°C or 159°C, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0040] Preferably, the first heating holding time is 25-35 min, for example, it can be 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min or 34 min, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0041] Preferably, the endpoint temperature of the second heating is 175-185°C, for example, it can be 176°C, 177°C, 178°C, 179°C, 180°C, 181°C, 182°C, 183°C or 184°C, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0042] Preferably, the second heating holding time is 25-35 min, for example, it can be 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min or 34 min, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0043] As a preferred technical solution of the present invention, after the circuit board is polished in step (3), the heights of the graphics, ink layer and cured conductive silver paste on the circuit board are consistent.

[0044] In the present invention, after the circuit board is ground, the pattern to be electroplated with gold needs to be exposed.

[0045] In the present invention, the method for removing ink is not specifically limited. Its function in the present invention is to remove excess ink. Those skilled in the art can select the method for removing ink according to actual conditions.

[0046] As a preferred technical solution of the present invention, the method for removing the conductive silver paste in step (4) includes any one of mechanical removal, chemical removal or thermal removal, or a combination of at least two of them.

[0047] In the present invention, the mechanical removal method uses a scraper or a brush or grinding to remove the conductive silver paste; the chemical removal method uses an organic solvent such as acetone or ethanol to soak and then wipe to remove; the thermal removal method uses hot air blowing or hot water washing and then wipe to remove.

[0048] In the present invention, after the conductive silver paste is removed, only the electroplated gold pattern is left on the circuit board. After the conductive silver paste is removed, the circuit board is subjected to conventional solder masking and forming to obtain a pattern-enclosed electroplated gold circuit board.

[0049] As a preferred technical solution of the present invention, before the gold electroplating in step (4), the process further includes: selectively coating the pattern of the circuit board with a dry film, then electroplating the gold, and then removing the dry film and the conductive silver paste in sequence.

[0050] In the present invention, if the product design requires that the proportion of the gold-plated pattern in the entire pattern is less than 100%, it is necessary to selectively coat the pattern of the circuit board with a dry film for masking after removing the ink.

[0051] Preferably, the selective coating of the dry film comprises sequentially performing pre-treatment, lamination, exposure and development.

[0052] In the present invention, the operation method of each step of selectively coating the dry film is not specifically limited, and those skilled in the art can adjust it according to actual conditions.

[0053] As a preferred technical solution of the present invention, the production method comprises the following steps:

[0054] (1) first printing ink with a viscosity of 60-180 mPa.s on the surface of the pretreated circuit board at a rate of 0.2-0.3 m / s, and then sequentially performing a first baking, exposure, development, and a second baking to form an ink layer;

[0055] During the first printing, the mesh size of the screen is 250-350 mesh, the pressure of the scraper is 20-30 kgf, and the angle is 60-80 degrees;

[0056] (2) grooving the ink layer to form grooves with a width of 5-10 mils;

[0057] The depth of the groove is the height of the ink layer;

[0058] (3) printing a second conductive silver paste in the groove at a rate of 0.2-0.6 m / s and curing the paste, and then grinding the circuit board to remove the ink;

[0059] During the second printing, the mesh size of the screen is 300-500 mesh, the pressure of the scraper is 10-60 kgf, and the angle is 10-20 degrees;

[0060] The curing comprises a first heating and a second heating in sequence; the end temperature of the first heating is 140-160°C and the holding time is 25-35 minutes; the end temperature of the second heating is 175-185°C and the holding time is 25-35 minutes;

[0061] (4) Electroplating the circuit board after removing the ink with gold, and then removing the conductive silver paste.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] The present invention improves the manufacturing method. First, ink is printed on the surface of the circuit board and solidified. Then, grooves are cut on the ink layer. Thereafter, conductive silver paste is printed in the grooves and solidified. This realizes the conductive path required for gold electroplating, effectively solves the problems of conductive wire residue or gold plating pattern gaps in the gold plating process of pulling conductive wires, and eliminates the need for etching, thereby reducing costs and improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Schematic diagram of a circuit board after pretreatment in Example 1 of the present invention;

[0065] Figure 2 Schematic diagram of a circuit board after grooves are formed in Example 1 of the present invention;

[0066] Figure 3 This is a schematic diagram of a circuit board after ink removal in Example 1 of the present invention;

[0067] Figure 4 Schematic diagram of a circuit board after gold electroplating in Example 1 of the present invention;

[0068] Figure 5 This is a schematic diagram of a circuit board after the conductive silver paste is removed in Example 1 of the present invention;

[0069] Figure 6 Schematic diagram of a circuit board after dry film coating in Example 2 of the present invention;

[0070] Figure 7 This is a schematic diagram of a circuit board after the conductive silver paste is removed in Example 2 of the present invention;

[0071] Among them, 100 is a circuit board, 101 is an ink layer, 102 is a groove, 103 is a cured conductive silver paste, 104 is a dry film, 105 is an electroless gold plating pattern, and 106 is an electrolytic gold plating pattern. DETAILED DESCRIPTION

[0072] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0073] In the following examples and comparative examples, the conductive silver pastes used were purchased from Ormet, Tatsuta, or other conductive silver paste manufacturers.

[0074] Example 1

[0075] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board, the method comprising the following steps:

[0076] (1) After pre-processing of the circuit board (such as Figure 1 The ink having a viscosity of 120 mPa.s is first printed on the surface at a rate of 0.25 m / s, and then subjected to a first baking, exposure at an energy of 2500 mJ, development, and a second baking in sequence to form an ink layer 101;

[0077] The pretreatment is to carry out material dispensing, inner layer, lamination, drilling, electroplating and etching in sequence to form a circuit board with patterns;

[0078] During the first printing, the mesh size of the screen is 300 mesh, the pressure of the scraper is 25 kgf, and the angle is 70°;

[0079] The curing is carried out in sequence by first baking at 60°C for 15 minutes, second baking at 75°C for 35 minutes, third baking at 90°C for 20 minutes, fourth baking at 120°C for 20 minutes and fifth baking at 155°C for 60 minutes;

[0080] (2) Laser grooving is performed on the ink layer 101 to form a groove 102 with a width of 7 mil (such as Figure 2 shown);

[0081] The depth of the groove 102 is equal to the height of the ink layer 101;

[0082] (3) Printing a second conductive silver paste in the groove at a rate of 0.4 m / s and curing the paste, grinding the circuit board to expose the pattern to be electroplated with gold, and the height of the pattern, ink layer and cured conductive silver paste on the circuit board is consistent, and then removing the ink (such as Figure 3 shown);

[0083] During the second printing, the mesh size of the screen is 400 mesh, the pressure of the scraper is 40 kgf, and the angle is 15°;

[0084] The curing comprises a first heating and a second heating in sequence; the end temperature of the first heating is 150°C and the holding time is 30 minutes; the end temperature of the second heating is 180°C and the holding time is 30 minutes;

[0085] (4) Electroplating the printed circuit board after removing the ink (such as Figure 4 ), and then the conductive silver paste is removed by thermal removal (as shown Figure 5 As shown), the circuit board is then subjected to solder masking and molding in sequence.

[0086] In this embodiment, the gold-plated pattern on the circuit board has no gaps.

[0087] Example 2

[0088] This embodiment provides a method for manufacturing gold plating on the surface of a circuit board, except that step (4) is adjusted to: selectively coating the circuit board after removing the ink with a dry film 104 (such as Figure 6 ), followed by gold plating, followed by removal of the dry film and conductive silver paste (as shown in Figure 7 As shown), the circuit board is then subjected to solder masking and molding in sequence; other conditions are the same as those in Example 1.

[0089] In this embodiment, the gold-plated pattern on the circuit board has no gaps.

[0090] Example 3

[0091] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board, the method comprising the following steps:

[0092] (1) first printing ink with a viscosity of 180 mPa.s on the surface of the pretreated circuit board at a rate of 0.2 m / s, and then sequentially performing a first baking, exposure at an energy of 2200 mJ, development, and a second baking to form an ink layer;

[0093] The pretreatment is to carry out material dispensing, inner layer, lamination, drilling, electroplating and etching in sequence to form a circuit board with patterns;

[0094] During the first printing, the mesh size of the screen is 250 mesh, the pressure of the scraper is 20 kgf, and the angle is 80°;

[0095] The curing is carried out in sequence by first baking at 60°C for 15 minutes, second baking at 75°C for 35 minutes, third baking at 90°C for 20 minutes, fourth baking at 120°C for 20 minutes and fifth baking at 155°C for 60 minutes;

[0096] (2) performing laser grooving on the ink layer to form a groove with a width of 5 mil;

[0097] The depth of the groove is the height of the ink layer;

[0098] (3) printing a second conductive silver paste in the groove at a rate of 0.6 m / s and curing the paste, and after grinding the circuit board, exposing the pattern to be electroplated with gold, and the height of the pattern, ink layer and cured conductive silver paste on the circuit board are consistent, and then removing the ink;

[0099] During the second printing, the mesh size of the screen is 300 mesh, the pressure of the scraper is 12 kgf, and the angle is 10°;

[0100] The curing comprises a first heating and a second heating in sequence; the end temperature of the first heating is 140°C and the holding time is 35 minutes; the end temperature of the second heating is 175°C and the holding time is 35 minutes;

[0101] (4) Electroplating gold is performed on the circuit board after the ink is removed, and then the conductive silver paste is removed by mechanical removal, and then the circuit board is sequentially subjected to solder masking and molding.

[0102] In this embodiment, the gold-plated pattern on the circuit board has no gaps.

[0103] Example 4

[0104] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board, the method comprising the following steps:

[0105] (1) first printing an ink with a viscosity of 60 MPa.s on the surface of the pretreated circuit board at a rate of 0.3 m / s, and then sequentially performing a first baking, exposure at an energy of 3000 mJ, development, and a second baking to form an ink layer;

[0106] The pretreatment is to carry out material dispensing, inner layer, lamination, drilling, electroplating and etching in sequence to form a circuit board with patterns;

[0107] During the first printing, the mesh size of the screen is 350 mesh, the pressure of the scraper is 30 kgf, and the angle is 60°;

[0108] The curing is carried out in sequence by first baking at 60°C for 15 minutes, second baking at 75°C for 35 minutes, third baking at 90°C for 20 minutes, fourth baking at 120°C for 20 minutes and fifth baking at 155°C for 60 minutes;

[0109] (2) performing laser grooving on the ink layer to form a groove with a width of 10 mil;

[0110] The depth of the groove is the height of the ink layer;

[0111] (3) printing a second conductive silver paste in the groove at a rate of 0.2 m / s and curing the paste, and after grinding the circuit board, exposing the pattern to be electroplated with gold, and the height of the pattern, ink layer and cured conductive silver paste on the circuit board are consistent, and then removing the ink;

[0112] During the second printing, the mesh size of the screen is 500 mesh, the pressure of the scraper is 60 kgf, and the angle is 20°;

[0113] The curing comprises a first heating and a second heating in sequence; the end temperature of the first heating is 160° C. and the holding time is 25 minutes; the end temperature of the second heating is 185° C. and the holding time is 25 minutes;

[0114] (4) Electroplating gold is performed on the circuit board after the ink is removed, and then the conductive silver paste is removed by mechanical removal, and then the circuit board is sequentially subjected to solder masking and molding.

[0115] In this embodiment, the gold-plated pattern on the circuit board has no gaps.

[0116] Example 5

[0117] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board. Except that the speed of the second printing in step (3) is 0.1 m / s, other conditions are the same as those in Example 1.

[0118] In this embodiment, when the printing speed of the conductive silver paste is too slow, since there is a certain proportion of diluent in the conductive silver paste, the diluent evaporates and causes the viscosity of the conductive silver paste to increase, affecting the printing effect and further affecting the efficiency of the second printing.

[0119] Example 6

[0120] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board. Except that the speed of the second printing in step (3) is 1 m / s, other conditions are the same as those in Example 1.

[0121] In this embodiment, when the conductive silver paste is printed too quickly, the gas in the groove cannot be completely discharged, which affects the filling effect of the conductive silver paste.

[0122] Example 7

[0123] This embodiment provides a method for manufacturing gold electroplating on the surface of a circuit board. Except that the pressure of the scraper during the second printing in step (3) is 5 kgf, other conditions are the same as those in Example 1.

[0124] In this embodiment, when printing the conductive silver paste, if the pressure of the scraper is too small, the primary filling degree of the conductive silver paste is affected.

[0125] Example 8

[0126] This embodiment provides a method for manufacturing gold electroplating on the surface of a circuit board. Except that the pressure of the scraper during the second printing in step (3) is 70 kgf, other conditions are the same as those in Example 1.

[0127] In this embodiment, when printing the conductive silver paste, if the pressure of the scraper is too great, the ink layer will be damaged and part of the conductive silver paste will be exposed.

[0128] Example 9

[0129] This embodiment provides a method for manufacturing gold electroplating on the surface of a circuit board. Except that the angle of the scraper is 5° during the second printing in step (3), other conditions are the same as those in Example 1.

[0130] In this embodiment, when printing the conductive silver paste, if the angle of the scraper is too small, part of the conductive silver paste that has been filled may be easily ejected.

[0131] Example 10

[0132] This embodiment provides a method for manufacturing gold electroplating on the surface of a circuit board. Except that the angle of the scraper is 30° during the second printing in step (3), other conditions are the same as those in Example 1.

[0133] In this embodiment, when printing the conductive silver paste, if the angle of the scraper is too large, part of the filled conductive silver paste may be easily ejected.

[0134] Example 11

[0135] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board. Except that the curing temperature in step (3) is 150° C. and the holding time is 60 minutes, i.e., a one-stage temperature rise curing is performed, other conditions are the same as those in Example 1.

[0136] In this embodiment, when only one stage of temperature rise is used to cure the conductive silver paste, the volatile substances in the conductive silver paste will evaporate unevenly, affecting the curing degree of the conductive silver paste and the final conductive silver paste path shape and conductive performance.

[0137] Example 12

[0138] This embodiment provides a method for manufacturing gold electroplated on the surface of a circuit board. Except that the curing temperature in step (3) is 180° C. and the holding time is 60 minutes, i.e., a one-stage temperature rise curing is performed, other conditions are the same as those in Example 1.

[0139] In this embodiment, when only one stage of temperature rise is used to cure the conductive silver paste, the volatile substances in the conductive silver paste will evaporate unevenly, affecting the curing degree of the conductive silver paste and the final conductive silver paste path shape and conductive performance.

[0140] Comparative Example 1

[0141] This comparative example provides a method for manufacturing gold electroplating on the surface of a circuit board. Except that step (2) is not performed, that is, a second printing of conductive silver paste is directly performed on the ink layer, other conditions are the same as those in Example 1.

[0142] In this comparative example, if the conductive silver paste is directly printed on the ink layer, the printed shape, area, and depth of the conductive silver paste cannot be controlled, and an effective conductive path cannot be formed.

[0143] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for manufacturing gold-plated circuit board surface, characterized in that: The production method comprises the following steps: (1) performing a first printing ink on the surface of the circuit board to form an ink layer; (2) grooving the ink layer to form grooves; (3) printing a second conductive silver paste in the groove and curing the paste, and then grinding the circuit board to remove the ink; (4) Electroplating the circuit board after removing the ink with gold, and then removing the conductive silver paste.

2. The production method according to claim 1, characterized in that Step (1) before the first printing, further comprising: pre-processing the circuit board; Preferably, the pretreatment includes sequentially performing material discharging, inner layer forming, lamination, drilling, electroplating and etching to form a circuit board with patterns.

3. The production method according to claim 1 or 2, characterized in that: The viscosity of the ink in step (1) is 60-180 mPa.s; Preferably, in step (1) during the first printing, the mesh size of the screen is 250-350 mesh; Preferably, during the first printing in step (1), the pressure of the scraper is 20-30 kgf; Preferably, during the first printing in step (1), the angle of the scraper is 60-80°; Preferably, the speed of the first printing in step (1) is 0.2-0.3 m / s; Preferably, after the first printing in step (1), the process further includes sequentially performing first baking, exposure, development and second baking.

4. The production method according to any one of claims 1 to 3, characterized in that The grooving method in step (2) includes laser grooving; Preferably, the depth of the groove in step (2) is the height of the ink layer; Preferably, the width of the groove in step (2) is 5-10 mil.

5. The production method according to any one of claims 1 to 4, characterized in that: Step (3) During the second printing, the mesh size of the screen is 300-500 mesh; Preferably, during the second printing in step (3), the pressure of the scraper is 10-60 kgf; Preferably, during the second printing in step (3), the angle of the scraper is 10-20°; Preferably, the speed of the second printing in step (3) is 0.2-0.6 m / s.

6. The production method according to any one of claims 1 to 5, characterized in that: The curing in step (3) includes a first temperature increase and a second temperature increase performed sequentially; Preferably, the endpoint temperature of the first heating is 140-160°C; Preferably, the first heating holding time is 25-35 minutes; Preferably, the endpoint temperature of the second heating is 175-185°C; Preferably, the second heating holding time is 25-35 minutes.

7. The production method according to any one of claims 1 to 6, characterized in that: After the circuit board is ground in step (3), the heights of the graphics, ink layer and cured conductive silver paste on the circuit board are consistent.

8. The production method according to any one of claims 1 to 7, characterized in that: The method for removing the conductive silver paste in step (4) includes any one of mechanical removal, chemical removal or thermal removal, or a combination of at least two of them.

9. The production method according to any one of claims 1 to 8, characterized in that: Before the gold electroplating in step (4), the method further includes: selectively coating the pattern of the circuit board with a dry film, then electroplating the gold, and then removing the dry film and the conductive silver paste in sequence; Preferably, the selective coating of the dry film comprises sequentially performing pre-treatment, lamination, exposure and development.

10. The production method according to any one of claims 1 to 9, characterized in that: The production method comprises the following steps: (1) first printing ink with a viscosity of 60-180 mPa.s on the surface of the pretreated circuit board at a rate of 0.2-0.3 m / s, and then sequentially performing a first baking, exposure, development, and a second baking to form an ink layer; During the first printing, the mesh size of the screen is 250-350 mesh, the pressure of the scraper is 20-30 kgf, and the angle is 60-80 degrees; (2) grooving the ink layer to form grooves with a width of 5-10 mils; The depth of the groove is the height of the ink layer; (3) printing a second conductive silver paste in the groove at a rate of 0.2-0.6 m / s and curing the paste, and then grinding the circuit board to remove the ink; During the second printing, the mesh size of the screen is 300-500 mesh, the pressure of the scraper is 10-60 kgf, and the angle is 10-20 degrees; The curing comprises a first heating and a second heating in sequence; the end temperature of the first heating is 140-160°C and the holding time is 25-35 minutes; the end temperature of the second heating is 175-185°C and the holding time is 25-35 minutes; (4) Electroplating the circuit board after removing the ink with gold, and then removing the conductive silver paste.

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