Low-copper-consumption circuit board electroplating method

Abstract

The invention discloses a low-copper-consumption circuit board electroplating method which comprises the following steps: providing an accompanying plating plate which comprises a working section which is used for plane diversion and is telescopic in the length direction and a clamping section which is formed by bending and extending one end of the working section, the width of the working section is 50-60mm, the length of the clamping section is 150-160mm, the width of the clamping section is 20-30mm, and the width of the clamping section is 20-30mm; an electrolytic corrosion resistant layer is arranged on the surface of the accompanying plating plate; feeding a to-be-plated circuit board; the accompanying plating plates are fixed to one side of a head plate and one side of a tail plate of the circuit board to be plated respectively, and the extending direction of the clamping sections of the accompanying plating plates is far away from the circuit board to be plated; the production data information of the circuit board to be plated is stored, the production data information comprises the specification size L * W, the length size of the accompanying plating board is automatically calculated according to the size of the circuit board, the length of the accompanying plating board is equal to L + (5-10) mm, and the length of the accompanying plating board is adjusted according to the size information; and carrying out vertical continuous electroplating, and dynamically adjusting current parameters according to the area of the working section of the accompanying plating plate, so that the electroplating uniformity CV value is less than 15%. According to the low-copper-consumption circuit board electroplating method provided by the invention, the production cost can be effectively reduced, the production efficiency is improved, and the copper plating uniformity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board production, and in particular to a low copper consumption circuit board electroplating method. Background Art

[0002] In the vertical continuous electroplating process for circuit boards, adjacent plating plates are required for the first and last boards to ensure that the current on the production board is the set current. In the existing technology, FR4 substrates are used as plating plates. The length of the plating plate is equal to the production board length + (10-20mm), and the width is 150mm. This has the following disadvantages:

[0003] 1. The accompanying plating board has a large plating area, which requires additional current to be shared. Usually, the current setting of one circuit board needs to be increased, which leads to increased copper consumption. In addition, the area occupied by the accompanying plating board results in an ineffective copper amount of 32-45%;

[0004] 2. The tin-removed accompanying plate cannot be recycled and needs to be cut and prepared every day, which consumes manpower and storage space;

[0005] 3. It is necessary to frequently replace the accompanying plating plates of different sizes according to the specifications of the circuit boards, which increases the downtime of the production line and affects production efficiency;

[0006] 4. Uneven current distribution: Due to the edge effect, the coating thickness on both sides of the flybar is abnormal (usually the coating thickness on both sides is 15-25um thicker than the middle area), resulting in uneven copper thickness distribution (CV value>35%), dry film interlayer defects (incidence>3%), and poor pattern transfer;

[0007] 5. Pollution risk: The falling of glass fiber burrs (size > 0.5mm) produced by cutting the accompanying plate will cause electroplated copper particle defects (PPM value increases by 50-80).

[0008] In view of this, it is necessary to provide a new process to solve the above technical problems. Summary of the Invention

[0009] The present invention aims to provide a low copper consumption circuit board electroplating method, which can effectively reduce production costs, improve production efficiency, and enhance copper plating uniformity.

[0010] The technical solutions of the present invention are as follows:

[0011] A low copper loss circuit board electroplating method comprises the following steps:

[0012] Step S1, providing a plating plate, the plating plate comprising a working section for planar flow diversion and being retractable in length, and a clamping section formed by bending and extending one end of the working section, the working section being 50-60 mm wide, the clamping section being 150-160 mm long and 20-30 mm wide, and the plating plate having an anti-electrolytic corrosion layer on its surface;

[0013] Step S2, preparing the circuit board to be plated;

[0014] Step S3, fixing a plating plate on one side of the first board and the last board of the circuit board to be plated, respectively, with the clamping section of the plating plate extending away from the circuit board to be plated;

[0015] Step S4, storing production data information of the circuit board to be plated, the production data information includes the specification size L×W, automatically calculating the length of the accompanying plating plate according to the size of the circuit board, the accompanying plating plate length = L+(5-10) mm, and adjusting the length of the accompanying plating plate according to the size information;

[0016] Step S5 , performing vertical continuous electroplating, dynamically adjusting current parameters according to the area of ​​the accompanying plating plate working section, so that the electroplating uniformity CV value is less than 15%.

[0017] Furthermore, the working section includes a body and a length adjustment structure connected to the body.

[0018] Furthermore, the length adjustment structure includes an adjustment plate, a slide groove provided on the adjustment plate, and a positioning locking device for locking the body and the adjustment plate.

[0019] Furthermore, the positioning and locking device includes a limit plate provided on one side of the adjustment plate, a bolt with one end connected to the body and the other end passing through the slide groove and the limit plate, and a locking nut connected to the bolt.

[0020] Furthermore, there are at least two groups of positioning and locking devices.

[0021] Furthermore, the accompanying plating plate is made of stainless steel, and the thickness of the main body and the adjustment plate is 1.2-1.5 mm.

[0022] Furthermore, a positioning scale is provided at the end of the adjustment plate.

[0023] Furthermore, the anti-electrolytic corrosion layer is a double-layer composite coating, which includes an inner layer and an outer layer, the inner layer is a chemical nickel plating layer, and the outer layer is a polytetrafluoroethylene layer.

[0024] Furthermore, the thickness of the inner layer is 5-8 um, and the thickness of the outer layer is 2-3 um.

[0025] Furthermore, in step S5, when performing vertical continuous electroplating, it also includes a step of real-time monitoring of the thickness of the coating, and adjusting the electroplating parameters according to the monitoring results.

[0026] Compared with the prior art, the low copper consumption circuit board electroplating method provided by the present invention has the following beneficial effects:

[0027] 1. The low-copper-consumption circuit board electroplating method provided by the present invention has an anti-electrolytic corrosion layer on the surface of the accompanying plating plate, and by optimizing the width of the working section of the accompanying plating plate to 50-60 mm, the plating area of ​​the accompanying plating plate is reduced, and there is no need to allocate additional current. Therefore, when setting the current, there is no need to increase the number of electroplated sheets, thereby reducing copper consumption and saving costs.

[0028] 2. The low copper consumption circuit board electroplating method provided by the present invention has an anti-electrolytic corrosion layer on the surface of the accompanying plate. After electroplating, it does not need to be manually removed to the tin stripping section of the alkaline etching line for tin stripping treatment. It can be reused after being peeled and hung in a nitric acid tank, thereby improving production efficiency and reducing the manpower and material resources consumed in daily cutting, preparation and tin stripping in the existing technology, and reducing storage space.

[0029] 3. The low copper consumption circuit board electroplating method provided by the present invention has a retractable working section of the accompanying plating plate, and the length of the working section of the accompanying plating plate is adjusted according to the size of the circuit board to be plated, so that the accompanying plating plate can be adapted to the electroplating of circuit boards of different specifications and sizes, reducing the production line downtime caused by frequent replacement of the accompanying plating plate and improving production efficiency.

[0030] 4. The low-copper-loss circuit board electroplating method provided by the present invention dynamically adjusts the current parameters based on the working section area of ​​the accompanying plating plate during electroplating, reduces the ineffective current distribution, reduces the CV value of the copper plating layer thickness uniformity from 35% to 12%, and reduces the film defect from 3‰ to 0.5‰, thereby improving the pattern transfer quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 creative work.

[0032] Figure 1 It is a structural schematic diagram of the accompanying plating plate in the present invention;

[0033] Figure 2 yes Figure 1 The schematic diagram of the B-direction structure of the accompanying plating plate shown;

[0034] Figure 3 yes Figure 1A schematic diagram of the cross-sectional structure of the accompanying plating plate along line AA;

[0035] Figure 4 It is a schematic diagram of the positional relationship between the accompanying plating plate and the plate to be plated in the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation methods of the present invention are further described below.

[0037] It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Please refer to Figure 1 and Figure 2 ,in Figure 1 It is a structural schematic diagram of the accompanying plating plate in the present invention; Figure 2 yes Figure 1 The accompanying plating plate 100 is shown as a schematic diagram of its B-axis structure. In the present invention, the accompanying plating plate 100 comprises a longitudinally extendable working section 1 and a clamping section 2 formed by bending and extending one end of the working section. The working section 1 is used for planar flow guidance, and the clamping section 2 is used for clamping the electroplating flybar to secure the accompanying plating plate.

[0039] In the present invention, the working section is 50-60mm wide, and the clamping section is 150-160mm long and 20-30mm wide. Compared to the prior art, the width of the working section of the accompanying plating plate of the present invention is designed to be 1 / 3 of the traditional width. The width of the clamping section 2 is 20-30mm, serving as a plating-proof area and only used for clamping and fixing the electroplating flybar. As a result, the plating area of ​​the accompanying plating plate of the present invention is reduced, and no additional current is required. Therefore, when setting the current, there is no need to increase the number of electroplated sheets, reducing copper and tin consumption and saving costs.

[0040] In the present invention, the working section 1 includes a main body 11 and a length adjustment structure 12 connected to the main body 11. The length adjustment structure 12 includes an adjustment plate 121, a slide 122 provided on the adjustment plate 121, and a positioning and locking device 123 for locking the main body 11 and the adjustment plate 121. Specifically, the positioning and locking device 123 includes a limit plate 124 provided on one side of the adjustment plate 121, a bolt 125 connected to the main body 11 at one end and passing through the slide 122 and the limit plate 124 at the other end, and a locking nut 126 connected to the bolt. Preferably, the positioning and locking device 123 is at least two groups, and by setting at least two positioning points, the stability of the length adjustment structure is ensured so that it does not deviate during the electroplating process. By adjusting the length of the working section, its length exceeds the circuit board to be plated by 5-10 mm. Specifically, a positioning scale 127 can be set at the end of the adjustment plate 121 to accurately control the length of the working section, wherein the end of the adjustment plate refers to one end of the principle clamping section.

[0041] In the present invention, the accompanying plating plate is made of stainless steel, and the thickness of the main body 11 and the adjustment plate 121 is 1.2-1.5 mm.

[0042] In the present invention, in order to prevent the accompanying plating plate from corroding during the electrolysis process, an anti-electrolytic corrosion layer is designed on its surface. Figure 3 , Figure 1 Schematic diagram of the cross-sectional structure of the accompanying plate along line AA. The anti-electrolytic corrosion layer 3 is a double-layer composite coating, comprising an inner layer 31 and an outer layer 32, wherein the inner layer 31 is a chemical nickel plating layer and the outer layer 32 is a polytetrafluoroethylene layer, wherein the inner layer thickness is 5-8 μm and the outer layer thickness is 2-3 μm.

[0043] In combination with the structure of the above accompanying plating plate, the present invention provides a low copper loss circuit board electroplating method, comprising the following steps:

[0044] Step S1, preparing a plating plate;

[0045] Step S2, loading the circuit board 200 to be plated;

[0046] Step S3, a plating plate 100 is fixed on one side of the first plate and the last plate of the circuit board to be plated, and the clamping section of the plating plate extends away from the circuit board to be plated; the positional relationship between the plating plate and the circuit board to be plated is as follows: Figure 4 As shown, the clamping sections of the circuit board to be plated and the accompanying plate are clamped and fixed by the electroplating Feiba 400;

[0047] Step S4, storing production data information of the circuit board to be plated, the production data information includes specification dimensions L×W, automatically calculating the length of the accompanying plating plate according to the circuit board dimensions, wherein the accompanying plating plate length = L+(5-10) mm, and adjusting the length of the accompanying plating plate according to the dimension information;

[0048] Step S5, performing vertical continuous electroplating, dynamically adjusting current parameters according to the area of ​​the accompanying plating plate working section, monitoring the coating thickness in real time, and adjusting electroplating parameters according to the monitoring results to make the electroplating uniformity CV value <15%.

[0049] Through testing, the consumption data of copper balls and tin balls using the electroplating process of the present invention are as follows:

[0050]

[0051] It can be seen from this that the electroplating process of the present invention can significantly reduce copper consumption, and based on the unit prices of copper balls and tin balls, it can be seen that the electroplating process of the present invention can significantly reduce production costs.

[0052] The electroplating process of the present invention reduces the CV value of copper thickness uniformity from 35% to 12%, and reduces the film defect from 3‰ to 0.5‰, thereby improving the pattern transfer quality.

[0053] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. A low copper loss circuit board electroplating method, characterized in that: The steps include: Step S1, providing a plating plate, the plating plate comprising a working section for planar flow diversion and being retractable in length, and a clamping section formed by bending and extending one end of the working section, the working section being 50-60 mm wide, the clamping section being 150-160 mm long and 20-30 mm wide, and the plating plate having an anti-electrolytic corrosion layer on its surface; Step S2, preparing the circuit board to be plated; Step S3, fixing a plating plate on one side of the first board and the last board of the circuit board to be plated, respectively, with the clamping section of the plating plate extending away from the circuit board to be plated; Step S4, storing production data information of the circuit board to be plated, the production data information includes the specification size L×W, automatically calculating the length of the accompanying plating plate according to the size of the circuit board, the accompanying plating plate length = L+(5-10) mm, and adjusting the length of the accompanying plating plate according to the size information; Step S5 , performing vertical continuous electroplating, dynamically adjusting current parameters according to the area of ​​the accompanying plating plate working section, so that the electroplating uniformity CV value is less than 15%.

2. The low copper loss circuit board electroplating method according to claim 1, characterized in that: The working section includes a body and a length adjustment structure connected to the body.

3. The low copper loss circuit board electroplating method according to claim 2, characterized in that: The length adjustment structure includes an adjustment plate, a slide groove provided on the adjustment plate, and a positioning locking device for locking the body and the adjustment plate.

4. The low copper loss circuit board electroplating method according to claim 3, characterized in that: The positioning and locking device includes a limiting plate provided on one side of the adjusting plate, a bolt with one end connected to the body and the other end passing through the slide groove and the limiting plate, and a locking nut connected to the bolt.

5. The low copper consumption circuit board electroplating method according to claim 4, characterized in that: There are at least two groups of positioning and locking devices.

6. The low copper loss circuit board electroplating method according to claim 3, characterized in that: The accompanying plating plate is made of stainless steel, and the thickness of the main body and the adjustment plate is 1.2-1.5 mm.

7. The low copper loss circuit board electroplating method according to claim 3, characterized in that: A positioning scale is provided at the end of the adjustment plate.

8. The low copper loss circuit board electroplating method according to claim 1, characterized in that: The anti-electrolytic corrosion layer is a double-layer composite coating, which includes an inner layer and an outer layer, the inner layer is a chemical nickel plating layer, and the outer layer is a polytetrafluoroethylene layer.

9. The low copper loss circuit board electroplating method according to claim 8, characterized in that: The thickness of the inner layer is 5-8um, and the thickness of the outer layer is 2-3um.

10. The low copper consumption circuit board electroplating method according to claim 1, characterized in that: In step S5, when performing vertical continuous electroplating, the method also includes a step of monitoring the thickness of the coating in real time, and adjusting the electroplating parameters according to the monitoring results.

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