Manufacturing method of gold-plated finger lead of storage module

Abstract

The invention relates to a method for manufacturing a gold-plated finger lead of a storage module, which comprises the following steps of: etching a copper-plated lead between a connecting finger and a main lead on a circuit board, reserving a first lead tail at a finger end, and reserving a second lead tail at a main lead end; a vacuum film laminator is adopted to attach the anti-gold-plating dry film to the circuit board; a carbon ink conductive bridge is printed on the circuit board, the carbon ink conductive bridge covers the gold-plating-resistant dry film, and the fingers and the main lead are conducted through the carbon ink conductive bridge; performing gold plating treatment on the circuit board to plate a gold layer on the surface of the finger to form a golden finger; and carrying out film removal treatment on the gold-plated circuit board, and removing the gold-plating-resistant dry film and the carbon ink conductive bridge. According to the manufacturing method, the carbon ink conductive bridge is used for replacing a traditional copper-plated lead, so that six processes such as reverse etching are omitted, the production process flow is simplified, and the material use cost is reduced.

Description

Technical Field

[0001] The present application relates to PCB processing technology, and in particular to a method for manufacturing gold-plated finger guides for storage modules. Background Art

[0002] The new generation of DDR5 memory module products, including So-dimm, U-dimm and R-dimm, have made significant improvements in the design of plug-in terminals compared to the 4th generation memory modules. In addition to the displacement design of the finger end, special requirements have been added to the lead tails left by the gold-plated leads at the end of the gold fingers. The original mechanical processing bevel chamfering to remove the leads has been changed to reverse etching to remove the signal fingers, and it is required that there should be no problem of reverse etching hanging gold. In response to the new product feature requirements, the industry currently generally uses LPI liquid ink to prime and fill the gaps in the drop area of ​​the substrate combined with a gold-resistant dry film to cover the surface, but this process is complicated, costly, and has many quality problems. Summary of the invention

[0003] In order to overcome the above-mentioned defects, the present application provides a method for manufacturing gold-plated finger guides for a storage module. The manufacturing method utilizes a carbon ink conductive bridge to replace the traditional copper-plated leads, thereby omitting six processes such as reverse etching, simplifying the production process and reducing material usage costs.

[0004] The technical solution adopted by this application to solve its technical problems is:

[0005] A method for manufacturing a gold-plated finger guide wire of a storage module, comprising the following processes:

[0006] Etching: Etch away the copper-plated leads between the connecting fingers and the main leads on the circuit board, and reserve the first lead tail at the finger end and the second lead tail at the main lead end, and then perform AOI and solder mask treatment on the circuit board;

[0007] Vacuum lamination: A vacuum laminator is used to attach the anti-gold plating dry film to the circuit board, and the fingers to be gold-plated are exposed through LPI exposure and development, and the first lead tail and the second lead tail are covered with the anti-gold plating dry film;

[0008] Printing carbon ink conductive bridges: printing carbon ink conductive bridges on the circuit board, wherein the carbon ink conductive bridges cover the anti-gold plating dry film, and the carbon ink conductive bridges conduct the fingers and the main leads;

[0009] Gold plating: gold plating the circuit board so that a layer of gold is plated on the surface of the finger to form a gold finger;

[0010] Gold plating film removal: the gold-plated circuit board is subjected to film removal treatment to remove the anti-gold plating dry film and the carbon ink conductive bridge.

[0011] Optionally, in the etching process: the length of the first lead tail is 5 mil±0.5 mil, and the length of the second lead tail is 10 mil±0.5 mil.

[0012] Optionally, in the vacuum lamination process, the length of the gold-plating-resistant dry film covering the first gold-plated lead and the second gold-plated lead is 1 mil±0.5 mil, and the thickness of the gold-plating-resistant dry film is 45 μm±5 μm.

[0013] Optionally, in the vacuum lamination process, the lamination parameters are: temperature 110°C ± 5°C, time 20s ± 3s, pressure 0.5-0.8Mpa, vacuuming time 10-20s, vacuum degree 1torr ± 0.5torr, and vacuum holding 10s ± 2s.

[0014] Optionally, in the vacuum lamination process, the parameters of LPI exposure are: exposure energy 500-800mj, energy 6 grids full, and development conditions are: Na2CO3 concentration 0.8-1.2wt%, pH value: 10.6-14; development line speed: 3.3±0.5m / min.

[0015] Optionally, in the carbon ink conductive bridge printing process, 200 mesh screen printing is used, the printing ink thickness is controlled to be ≥40μm, and the baking temperature after carbon ink printing is 120℃±10℃ and the time is 30min±5min; baking is performed after printing, and after baking, the resistance value is controlled at 1.5±0.5Ω.

[0016] Optionally, before gold plating, tape is attached to the edges of the circuit board and fingers, and the tape needs to cover the gold-plated carbon ink conductive bridge.

[0017] Optionally, in the gold plating film removal, NaOH with a mass concentration of 4%-6% is used to remove the anti-gold plating dry film and the carbon ink conductive bridge; the operating conditions are: the line speed is 2m / min.

[0018] The beneficial effects of the present application are as follows: in the present application, a carbon ink conductive bridge is used to replace the traditional copper-plated lead, the carbon ink conductive bridge is connected to the main lead and the finger, and the carbon ink conductive bridge is printed on the surface of the anti-gold plating dry film. After the gold plating is completed, the film removal process can remove the anti-gold plating dry film and the carbon ink conductive bridge together, thereby omitting six processes such as reverse etching, simplifying the production process, reducing the material usage cost, and reducing the overall cost by about 200%, so that the process has the ability to be introduced into mass production, and the production is simple and controllable, which effectively solves the problems of copper leakage on the side after reverse etching, suspended gold loss and gold plating infiltration, and the lead residue of the gold finger can be controlled below 0.05mm, meeting customer requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the circuit board after the anti-gold plating dry film is affixed in this application;

[0020] Figure 2 This is a schematic diagram of the structure of the circuit board after the carbon ink conductive bridge is printed in this application;

[0021] Figure 3 This is a schematic diagram of the structure of the circuit board after the tape is applied in this application;

[0022] Figure 4 This is a schematic diagram of the structure of the circuit board after gold plating in this application;

[0023] Figure 5 This is a schematic diagram of the structure of the circuit board after film removal in this application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the embodiments described in the present application are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the following drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the objects used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0027] A method for manufacturing a gold-plated finger guide wire of a storage module, comprising the following processes:

[0028] Etching: Etch away the copper-plated leads between the connecting fingers and the main leads on the circuit board, and reserve the first lead tail at the finger end and the second lead tail at the main lead end, and then perform AOI and solder mask treatment on the circuit board;

[0029] Vacuum lamination: A vacuum laminator is used to attach the anti-gold plating dry film to the circuit board, and the LPI exposure and development are performed to expose the fingers to be gold plated, and the first lead tail and the second lead tail are covered with the anti-gold plating dry film; Figure 1 As shown, the fingers and the main leads are covered with a gold-resistant dry film;

[0030] Printing of carbon ink conductive bridge: printing a carbon ink conductive bridge on the circuit board, wherein the carbon ink conductive bridge covers the anti-gold plating dry film, and the carbon ink conductive bridge conducts the finger and the main lead; Figure 2 As shown, the carbon ink conductive bridge covers the first lead tail and the second lead tail to connect the finger to the main lead, thereby replacing the traditional copper lead;

[0031] Gilding: As Figure 4 As shown, the circuit board is subjected to gold plating so that a layer of gold is plated on the surface of the finger to form a gold finger;

[0032] Gold plating film removal: Figure 5 As shown, the gold-plated circuit board is subjected to a film removal process to remove the anti-gold plating dry film and the carbon ink conductive bridge.

[0033] In the present application, a carbon ink conductive bridge is used to replace the traditional copper-plated lead. The carbon ink conductive bridge is connected to the main lead and the finger, and the carbon ink conductive bridge is printed on the surface of the anti-gold plating dry film. After the gold plating is completed, the film removal process can remove the anti-gold plating dry film and the carbon ink conductive bridge together, thereby omitting six processes such as reverse etching, simplifying the production process, reducing the material usage cost, and reducing the overall cost by about 200%. The process has the ability to be introduced into mass production, and the production is simple and controllable. The problems of copper leakage on the side after reverse etching, suspended gold loss and gold plating infiltration are effectively solved, and the lead residue of the gold finger can be controlled below 0.05mm to meet customer requirements.

[0034] In the etching process: the length of the first lead tail is 5mil±0.5mil, and the length of the second lead tail is 10mil±0.5mil. The spacing between the first lead tail and the second lead tail can be dynamically adjusted according to the PCS layout spacing, and the length of the first lead tail is reasonably controlled to ensure that the lead residue of the gold finger of the final product is controlled below 0.05mm.

[0035] In the vacuum lamination process, the length of the anti-gold plating dry film covering the first gold-plated lead and the second gold-plated lead is 1 mil ± 0.5 mil, and the thickness of the anti-gold plating dry film is 45 μm ± 5 μm. During lamination, the anti-gold plating dry film is attached to the finger and fills the L-shaped corner between the side of the finger and the substrate to prevent the gold plating solution from penetrating gold.

[0036] In the vacuum lamination process, the lamination parameters are: temperature 110℃±5℃, time 20s±3s, pressure 0.5-0.8Mpa, vacuum time 10-20s, vacuum degree 1torr±0.5torr, vacuum holding 10s±2s. Among them, 1torr=1.333mbar=133.322pa.

[0037] In the vacuum lamination process, the parameters of LPI exposure are: exposure energy 500-800mj, energy 6 grids full, development conditions: Na2CO3 concentration 0.8-1.2wt%, pH value: 10.6-14; development line speed: 3.3±0.5m / min.

[0038] In the carbon ink conductive bridge printing process, 200 mesh screen printing is used, the printing ink thickness is controlled to be ≥40μm, and the baking temperature after carbon ink printing is 120℃±10℃ and the time is 30min±5min to facilitate secondary removal; baking is performed after printing. After baking, a multimeter is used to detect the conductive bridge resistance, and the resistance value is controlled at 1.5±0.5Ω.

[0039] Before gilding, Figure 3 As shown, the edges of the circuit board and the fingers are affixed with tape, and the tape needs to cover the gold-plated carbon ink conductive bridge. After the gold plating is completed, the tape is torn off.

[0040] In the gold plating film stripping, NaOH with a mass concentration of 4%-6% is used to remove the anti-gold plating dry film and carbon ink conductive bridge; the operating conditions are: the line speed is 2m / min. The sodium hydroxide solution can be used to remove the anti-gold plating dry film and the carbon ink conductive bridge at the same time. The film stripping is clean and has no residue. The film stripping line increases the maintenance frequency, and the film stripping tank is cleaned once every 4 hours.

[0041] Embodiment 1: A method for manufacturing a gold-plated finger guide wire of a storage module, comprising the following processes:

[0042] Step 1: Etching: Etch away the copper-plated leads between the fingers and the main leads on the circuit board, and reserve a first lead tail at the finger end and a second lead tail at the main lead end, and then perform AOI and solder mask treatment on the circuit board, wherein the length of the first lead tail is about 5 mils, and the length of the second lead tail is about 10 mils;

[0043] Step 2: Vacuum lamination: Figure 1 As shown, a vacuum laminator is used to attach the anti-gold plating dry film to the circuit board, and the fingers to be gold-plated are exposed through LPI exposure and development, and the first lead tail and the second lead tail are covered with the anti-gold plating dry film; wherein, the length of the anti-gold plating dry film covering the first lead tail is 1mil±0.5mil, and the thickness of the anti-gold plating dry film is about 45μm;

[0044] Lamination parameters: temperature 110℃±5℃, time 20 seconds, pressure 0.5-0.8Mpa, vacuum time 10-20 seconds, vacuum degree 1torr, vacuum hold 10 seconds;

[0045] LDI exposure: exposure energy 500-800mj, energy 6 grids full, developing Na2CO3 concentration 0.8-1.2wt%, pH value: 10.6-14; developing line speed: 3.3±0.5m / min;

[0046] Step 3: Carbon ink conductive bridge printing: Figure 2 As shown, a carbon ink conductive bridge is printed on the circuit board, the carbon ink conductive bridge covers the anti-gold plating dry film, and the carbon ink conductive bridge conducts the finger and the main lead; 200 mesh screen printing is adopted, the printing ink thickness is controlled to be ≥40μm, the width of the carbon ink conductive bridge and the width of the second lead tail are both about 0.15mm, and the length of the carbon ink conductive bridge covering the first lead tail is about 3mil. After the carbon ink is printed, it is baked at 120℃*30 minutes to facilitate secondary removal; after baking, a multimeter is used to detect the resistance of the conductive bridge, and the resistance value control range is: 1.5±0.5Ω;

[0047] Step 4: Figure 3 As shown, the gold-plated front panel edge and fingers need to be taped, and the tape needs to cover the gold-plated carbon ink conductive bridge;

[0048] Step 5: Gold plating: Figure 4 As shown, the circuit board is subjected to gold plating so that a layer of gold is plated on the surface of the finger to form a gold finger;

[0049] Step 6: Gold plating removal: Figure 5 As shown, the gold-plated circuit board is subjected to film stripping treatment to remove the anti-gold-plating dry film and the carbon-ink conductive bridge; NaOH with a mass concentration of 4%-6% is used to remove the anti-gold-plating dry film and the carbon-ink conductive bridge; operating conditions: the line speed is 2m / min, and the film stripping is clean and residue-free; the film stripping line increases the maintenance frequency, and the film stripping tank is cleaned once every 4H;

[0050] Step 7: Finally, carry out the following steps: plate warping → molding → beveling → testing → visual inspection → packaging to obtain the product.

[0051] It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these modifications and improvements are all within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for manufacturing a gold-plated finger guide wire of a storage module, characterized in that: Including the following processes: Etching: Etch away the copper-plated leads between the connecting fingers and the main leads on the circuit board, and reserve the first lead tail at the finger end and the second lead tail at the main lead end, and then perform AOI and solder mask treatment on the circuit board; Vacuum lamination: A vacuum laminator is used to attach the anti-gold plating dry film to the circuit board, and the fingers to be gold-plated are exposed through LPI exposure and development, and the first lead tail and the second lead tail are covered with the anti-gold plating dry film; Printing carbon ink conductive bridges: printing carbon ink conductive bridges on the circuit board, the carbon ink conductive bridges covering the anti-gold plating dry film, and the carbon ink conductive bridges connecting the fingers and the main leads; Gold plating: gold plating the circuit board so that a layer of gold is plated on the surface of the finger to form a gold finger; Gold plating film removal: the gold-plated circuit board is subjected to film removal treatment to remove the anti-gold plating dry film and the carbon ink conductive bridge.

2. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the etching process: the length of the first lead tail is 5mil±0.5mil, and the length of the second lead tail is 10mil±0.5mil.

3. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the vacuum lamination process, the length of the anti-gold plating dry film covering the first gold-plated lead and the second gold-plated lead is 1 mil±0.5 mil, and the thickness of the anti-gold plating dry film is 45 μm±5 μm.

4. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the vacuum lamination process, the lamination parameters are: temperature 110℃±5℃, time 20s±3s, pressure 0.5-0.8Mpa, vacuum time 10-20s, vacuum degree 1torr±0.5torr, vacuum holding 10s±2s.

5. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the vacuum lamination process, the parameters of LPI exposure are: exposure energy 500-800mj, energy 6 grids full, development conditions: Na2CO3 concentration 0.8-1.2wt%, pH value: 10.6-14; development line speed: 3.3±0.5m / min.

6. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the carbon ink conductive bridge printing process, 200 mesh screen printing is used, the printing ink thickness is controlled to be ≥40μm, the baking temperature after carbon ink printing is 120℃±10℃, and the time is 30min±5min; baking is performed after printing, and after baking, the resistance value is controlled at 1.5±0.5Ω.

7. The method for manufacturing a gold-plated finger guide for a storage module according to claim 1, characterized in that: Before gold plating, tape is pasted on the edges of the circuit board and fingers, and the tape needs to cover the gold-plated carbon ink conductive bridge.

8. The method for manufacturing a gold-plated finger-tip trace of a storage module according to claim 1, characterized in that: In the gold plating film removal, NaOH with a mass concentration of 4%-6% is used to remove the anti-gold plating dry film and the carbon ink conductive bridge; the operating conditions are: the line speed is 2m / min.

Images