PCB surface gold immersion and OSP processing method

Abstract

The embodiment of the invention provides a PCB surface gold immersion and OSP treatment method. The method comprises the following steps: carrying out super roughening treatment on a PCB by adopting a super roughening liquid medicine; carrying out green oil treatment on the PCB; carrying out post curing processing on the PCB; carrying out sand blasting micro-etching treatment on the PCB; manufacturing a dry film on the surface of the PCB, wherein the dry film is made of an immersion gold resistant dry film and correspondingly covers the area, requiring OSP surface treatment, of the surface of the PCB; performing gold immersion processing on the PCB; sequentially carrying out the following treatment on the PCB: film stripping, drying, forming, board washing, ET and appearance inspection; and performing OSP processing on the PCB qualified in appearance inspection to obtain a finished product. According to the method, the PCB is subjected to the super-roughening treatment firstly, the binding force of the board surface, the hole wall of the via hole and the surface printing ink can be improved, the oil removal pretreatment procedure needed in the traditional gold immersion treatment step can be omitted by manufacturing the dry film on the surface of the PCB, the process is simpler, and the surface treatment efficiency of the PCB is effectively improved.

Description

Technical Field

[0001] The embodiment of the present invention relates to the technical field of PCB surface treatment, and in particular to a PCB surface immersion gold and OSP processing method. Background Art

[0002] At present, in order to improve the welding performance of printed circuit boards (PCBs) and the good antioxidant performance or wear resistance of local areas, two surface treatment processes, immersion gold and OSP (Organic Solderability Preservatives, also known as copper protectants, are a copper foil surface treatment process that complies with the requirements of the RoHS directive) are usually implemented in PCBA. When immersion gold is performed, the pad area to be treated with OSP needs to be covered with a masking material (such as dry film or peelable adhesive). However, because the dry film is not resistant to gold, the dry film is easily broken during the immersion gold treatment process, causing the chemical to contaminate the OSP-treated pad, resulting in discoloration of the OSP-treated pad. Although the peelable adhesive will not have the problem of chemical contamination of the OSP pad, it is difficult to tear the peelable adhesive clean, resulting in adhesive residue on the board surface, which is difficult to clean and has low efficiency. Summary of the invention

[0003] The technical problem to be solved by the embodiment of the present invention is to provide a method for PCB surface immersion gold and OSP processing, which can effectively implement immersion gold and OSP processing on the PCB surface.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a PCB surface immersion gold and OSP processing method, comprising the following steps: Use super roughening solution to perform super roughening treatment on PCB, so that the PCB surface and the via hole wall are corroded and meet the predetermined roughness requirements; Performing green oil treatment on the super-roughened PCB; Performing post-curing treatment on the PCB treated with green oil; Performing sandblasting and micro-etching treatment on the PCB after post-curing treatment to make the board surface of the PCB clean; Making a dry film on the surface of the PCB treated with sandblasting and microetching, wherein the dry film is made of a dry film resistant to immersion gold and covers the area of ​​the PCB surface requiring OSP surface treatment; Performing immersion gold treatment on the PCB with the dry film attached thereto; The PCB that has been treated with immersion gold is processed in the following ways: film stripping, drying, molding, board washing, ET and appearance inspection; The PCB that has passed the appearance inspection is subjected to OSP treatment to obtain the finished product.

[0005] Furthermore, during the super-roughening treatment, the micro-etching amount ranges from 1.1 to 1.2 um.

[0006] Furthermore, the following step is performed between the green oil treatment and green oil post-curing steps: printing text information on the PCB surface.

[0007] Furthermore, during the sandblasting micro-etching treatment, the sandblasting concentration is prepared according to the ratio of adding 55-60 kg of corundum powder to every 300 L of water, the sandblasting speed is 2.0±0.2 m / min, and the micro-etching amount is controlled within the range of 0.3-0.8 um.

[0008] Furthermore, the dry film is made of DuPont 250 dry film, and after film application, it needs to be left to stand for at least 1 hour before exposure, and after exposure, it needs to be left to stand for at least 2 hours before development.

[0009] Furthermore, when performing the immersion gold treatment, the following control parameters are used: The PCB that has completed the previous steps must be put into the tank within 2 hours; The temperature of the nickel cylinder is controlled at 78-79℃; The nickel deposition time is controlled at 1400±10 seconds; The temperature of the gold cylinder is controlled at 87-89℃; and.

[0010] The gold sinking time of the gold cylinder is controlled at 600±5 seconds.

[0011] By adopting the above technical scheme, the embodiment of the present invention has at least the following beneficial effects: the present invention performs super-roughening treatment on the PCB before the green oil treatment, which is beneficial to improving the bonding strength between the board surface and the via hole wall and the surface ink, and also makes a dry film on the PCB surface, which can save the degreasing pre-treatment process required in the traditional immersion gold treatment step, the process is simpler, and the PCB surface treatment efficiency is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0013] Figure 1 The present invention is a method flow chart of an optional embodiment of the PCB surface gold deposition and OSP processing method of the present invention. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0015] In addition, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally means that the associated objects before and after are in an "or" relationship.

[0016] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0017] like Figure 1 As shown, an embodiment of the present invention provides a PCB surface immersion gold and OSP processing method, comprising the following steps: S1, using super roughening solution to perform super roughening treatment on the PCB, so that the PCB surface and the via hole wall are corroded and meet the predetermined roughness requirements; S2, performing green oil treatment on the PCB that has undergone the super-roughening treatment; S3, printing text information on the PCB surface; S4, performing post-curing treatment on the PCB treated with green oil; S5, performing sandblasting and micro-etching treatment on the PCB after the post-curing treatment to make the board surface of the PCB clean; S6, making a dry film on the surface of the PCB that has been subjected to sandblasting and microetching treatment, wherein the dry film is made of a gold-resistant dry film and covers the area of ​​the PCB surface that requires OSP surface treatment; S7, performing immersion gold treatment on the PCB with the dry film attached thereto; S8, the PCB that has been treated with immersion gold is processed in the following ways: film stripping, drying, molding, board washing, ET (Electrical Testing) and appearance inspection; S9, perform OSP treatment on the PCB that has passed the appearance inspection to obtain the finished product.

[0018] It is understandable that the above step S3 is optional, that is, when there is no need to print corresponding text information (such as product model, production number / date, manufacturer information, etc.), this step can be omitted.

[0019] The present invention performs super-roughening treatment on the PCB before green oil treatment, which is beneficial to improving the bonding strength between the board surface and the via hole wall and the surface ink. In specific implementation, the super-roughening solution can be: super-roughening micro-etching liquid BTH-2086B supplementer, super-roughening micro-etching agent BTH-2086A cylinder opener, etc. produced and sold by Banming Company; in addition, dry film is also made on the PCB surface, and the degreasing pre-treatment process required in the traditional immersion gold treatment step can be omitted, the process is simpler, and the PCB surface treatment efficiency is effectively improved.

[0020] In an optional embodiment of the present invention, during the ultra-roughening treatment, the micro-etching amount ranges from 1.1 to 1.2 um. By reasonably controlling the micro-etching amount, this embodiment can not only make the PCB board surface and the via hole wall have a better bonding force, but also control the ultra-roughening treatment time within an appropriate range to ensure the treatment efficiency.

[0021] In another optional embodiment of the present invention, during the sandblasting micro-etching treatment, the sandblasting concentration is prepared according to the ratio of adding 55-60Kg of corundum powder to every 300L of water, the sandblasting speed is 2.0±0.2m / min, and the micro-etching amount is controlled within the range of 0.3-0.8um. ​​This embodiment can effectively purify the PCB surface by adopting appropriate sandblasting concentration and sandblasting speed, and controlling the micro-etching amount.

[0022] In another optional embodiment of the present invention, the dry film is made of DuPont 250 dry film, and after film application, it needs to be left to stand for at least 1 hour before exposure, and after exposure, it needs to be left to stand for at least 2 hours before development. In this embodiment, by using DuPont 250 dry film to make dry film and performing effective time control during the production process, high-quality dry film can be obtained, so that there is no need to perform a degreasing pre-treatment process during the subsequent immersion gold treatment.

[0023] In another optional embodiment of the present invention, when performing the immersion gold treatment, the operation is performed according to the following control parameters: The PCB that has completed the previous steps must be put into the tank within 2 hours; The temperature of the nickel cylinder is controlled at 78-79℃; The nickel deposition time is controlled at 1400±10 seconds; The temperature of the gold cylinder is controlled at 87-89℃; and.

[0024] The gold sinking time of the gold cylinder is controlled at 600±5 seconds.

[0025] This embodiment adopts the above-mentioned operation control for the immersion gold treatment, which can effectively improve the efficiency and quality of the immersion gold treatment. For example, the temperature of the nickel cylinder and the gold cylinder and the duration of the nickel and gold immersion processes are reasonably set, and the degreasing process in the traditional immersion gold process is not required, which can effectively avoid the occurrence of dry film abnormalities such as spin-drying film, and is also beneficial to improving the quality and efficiency of immersion gold treatment. Since the previous step S5 has been subjected to sandblasting and micro-etching treatment, there is no need to perform sandblasting and micro-etching treatment during the immersion gold treatment. Only simple water washing is required when necessary, without the complicated immersion gold pre-treatment in the traditional process. By putting the PCB that has completed the previous step into the cylinder for immersion gold treatment in a relatively short time, it can be avoided that the surface is contaminated and the immersion gold quality is affected.

[0026] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many variations without departing from the creative purpose of the present invention and the scope of protection of the claims, which all fall within the scope of protection of this patent.

Claims

1. A method for PCB surface immersion gold and OSP processing, characterized in that: The following steps are involved: Use super roughening solution to perform super roughening treatment on PCB, so that the PCB surface and the via hole wall are corroded and meet the predetermined roughness requirements; Performing green oil treatment on the super-roughened PCB; Post-curing the PCB treated with green oil; Performing sandblasting and micro-etching treatment on the PCB after post-curing treatment to make the board surface of the PCB clean; Making a dry film on the surface of the PCB treated with sandblasting and microetching, wherein the dry film is made of a dry film resistant to immersion gold and covers the area of ​​the PCB surface requiring OSP surface treatment; Performing immersion gold treatment on the PCB with the dry film attached thereto; The PCB that has been treated with immersion gold is processed in the following ways: film stripping, drying, molding, board washing, ET and appearance inspection; The PCB that has passed the appearance inspection is subjected to OSP treatment to obtain the finished product.

2. The PCB surface immersion gold and OSP processing method according to claim 1, characterized in that: During the super-roughening treatment, the micro-etching amount ranges from 1.1 to 1.2 um.

3. The PCB surface immersion gold and OSP processing method according to claim 1, characterized in that: The following step is performed between the green oil treatment and green oil post-curing steps: printing text information on the PCB surface.

4. The PCB surface immersion gold and OSP processing method according to claim 1, characterized in that: During the sandblasting micro-etching treatment, the concentration of the sandblasting is prepared according to the ratio of adding 55-60 kg of corundum powder to every 300 liters of water, the sandblasting speed is 2.0 ± 0.2 m / min, and the micro-etching amount is controlled within the range of 0.3-0.8 um.

5. The PCB surface immersion gold and OSP processing method according to claim 1, characterized in that: The dry film is made of DuPont 250 dry film. After film application, it needs to be left to stand for at least 1 hour before exposure. After exposure, it needs to be left to stand for at least 2 hours before development.

6. The PCB surface immersion gold and OSP processing method according to claim 1, characterized in that: When performing immersion gold treatment, operate according to the following control parameters: The PCB that has completed the previous steps must be put into the tank within 2 hours; The temperature of the nickel cylinder is controlled at 78-79℃; The nickel deposition time is controlled at 1400±10 seconds; The temperature of the gold cylinder is controlled at 87-89℃; and The gold sinking time of the gold cylinder is controlled at 600±5 seconds.

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