Phosphorus-free and high-galvanic-resistance micro-etching liquid for OSP pretreatment

Abstract

The invention discloses a non-phosphorus anti-galvanic strong micro-etching liquid for OSP pretreatment. The non-phosphorus anti-galvanic strong micro-etching liquid comprises the following components: 10-300 g / L of hydrogen peroxide, 0-150 g / L of sulfuric acid, 0.1-10 g / L of a hydrogen peroxide stabilizer, 1-50 g / L of organic acid, 0.1-20 g / L of an etching rate stabilizer, 0.1-10 g / L of organic alkali and water as a solvent. The micro-etching liquid has the advantages of no phosphorus, high galvanic resistance, uniform and glossy copper surface after micro-etching, uniform OSP film thickness and the like, the qualified rate of final finished products can be greatly improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electronic chemicals for printed circuit boards, and in particular to a phosphorus-free, galvanne-resistant, OSP pre-treatment micro-etching solution. Background Art

[0002] As electronic products develop towards miniaturization, intelligence, safety and multifunctionality, PCBs are required to be miniaturized, environmentally friendly and have high wiring density. The surface treatment process of printed circuit boards is moving towards halogen-free, lead-free, high solderability and high stability. The traditional single surface treatment method can no longer meet the requirements. Composite surface treatment combines the advantages of multiple surface treatment processes and is widely used. In the processing of some high-end circuit boards, chemical nickel-gold + OSP process is often used as the final surface treatment. However, this process has a very troubling problem. The Giovanni Effect is also called the Raw Cell Effect. When two or more different active metals (such as copper (Cu) and gold (Au)) are connected and passed through the OSP micro-etching solution (electrolyte), an electrochemical reaction occurs due to the difference in electromotive force (potential difference). At this time, the more active metal will lose electrons and undergo oxidation reaction, resulting in defects such as pad shrinkage, no copper at the orifice and open circuit, which seriously affects the reliability of the product and the qualified rate of finished products. With the progress of society and the enhancement of people's environmental awareness, phosphorus pollution has attracted widespread attention. Phosphorus discharge will cause eutrophication of surrounding waters and may cause "red tides". In some countries such as Europe, the United States, and Japan, phosphorus ban measures have been proposed. For example, Germany requires phosphorus discharge ≤ 1 mg·L-1.

[0003] At present, the common OSP micro-etching solutions include sulfuric acid / hydrogen peroxide system, sulfuric acid / persulfate system and phosphoric acid / hydrogen peroxide system, none of which can simultaneously solve the problems of being phosphorus-free, having strong resistance to galvanic acid, having good OSP film appearance, and having strong deoxidation. In view of the above problems, it is now necessary to develop a micro-etching solution suitable for OSP pretreatment that is phosphorus-free, has strong resistance to galvanic acid, has strong deoxidation, and has good OSP appearance, which can greatly improve the qualified rate of the final product and reduce production costs. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a phosphorus-free and galvanic-resistant OSP pre-treatment micro-etching solution, which has the advantages of being phosphorus-free, galvanic-resistant, uniform gloss on the copper surface after micro-etching, and uniform OSP film thickness. It can greatly improve the qualified rate of the final product and reduce production costs.

[0005] The technical scheme of the present invention is: a phosphorus-free and galvanne-resistant OSP pretreatment micro-etching solution, comprising the following components: 10-300 g / L hydrogen peroxide, 0-150 g / L sulfuric acid, 0.1-10 g / L hydrogen peroxide stabilizer, 1-50 g / L organic acid, 0.1-20 g / L etching rate stabilizer, 0.1-10 g / L organic base, and the solvent is water.

[0006] Furthermore, the hydrogen peroxide has a concentration of 35%; the hydrogen peroxide is controlled between 60-150 g / L.

[0007] Furthermore, the amount of sulfuric acid added is 0-8 g / L.

[0008] Furthermore, the hydrogen peroxide stabilizer is one or more of amide substances, or one or more of benzenesulfonic acid substances.

[0009] Furthermore, the organic acid is one or more of carboxylic acids, or one or more of sulfonic acids.

[0010] Furthermore, the etching rate stabilizer includes one or more alcohol ether substances.

[0011] The phosphorus-free and galvanne-resistant OSP pretreatment micro-etching solution according to claim 1 is characterized in that the organic base comprises one or more of cyclohexylamine, dihydroxyethylcyclohexylamine, ethanolamine, diethanolamine, and triethanolamine.

[0012] The beneficial effects of the present invention are: The micro-etching liquid does not contain phosphorus, has strong resistance to galvanic acid, has uniform gloss on the copper surface after micro-etching, uniform OSP film thickness and stable etching rate, etc. It can greatly improve the qualified rate of the final product and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0014] Figure 1 Design drawing for the anti-Jiafanni test version.

[0015] Figure 2 For the anti-Jiafan test process.

[0016] Figure 3 This is the appearance of the film after Example 1.

[0017] Figure 4 This is the appearance picture after the film of Example 2.

[0018] Figure 5 This is the appearance picture of the film after the comparative example 1 was filmed.

[0019] Figure 6This is the appearance picture of comparative example 2 after film coating. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below through specific implementation methods.

[0021] The phosphorus-free and galvanne-resistant OSP pretreatment micro-etching solution of the present invention comprises the following components: 10-300 g / L hydrogen peroxide, 0-150 g / L sulfuric acid, 0.1-10 g / L hydrogen peroxide stabilizer, 1-50 g / L organic acid, 0.1-20 g / L etching rate stabilizer, 0.1-10 g / L organic base, and the solvent is water. Example 1

[0022] The phosphorus-free, galvanne-resistant OSP pre-treatment micro-etching solution of this embodiment includes the following components: 100 g / L hydrogen peroxide (35%), 2 g / L sulfuric acid, 15 g / L glycolic acid, 1 g / L 4-hydroxybenzenesulfonic acid, 1 g / L ethylene glycol, 2 g / L dihydroxyethylcyclohexylamine, and the rest is water. Example 2

[0023] The phosphorus-free, galvanne-resistant OSP pre-treatment micro-etching solution of this embodiment includes the following components: 150 g / L hydrogen peroxide (35%), 20 g / L citric acid, 1 g / L 4-hydroxybenzenesulfonic acid, 1 g / L propylene glycol, 2 g / L cyclohexylamine, and the rest is water.

[0024] Comparative Example 1 The micro-etching solution of this embodiment adopts a sulfuric acid-hydrogen peroxide system: 30 g / L sulfuric acid, 30 g / L hydrogen peroxide, 1 g / L p-hydroxybenzenesulfonic acid, 2 g / L 1,4-butanediol, and the rest is water.

[0025] Comparative Example 2 The micro-etching solution of this embodiment adopts a sulfuric acid-potassium peroxymonosulfate complex salt system: 30 g / L sulfuric acid, 40 g / L potassium peroxymonosulfate complex salt, and the rest is water. Example 3

[0026] A PCB production process including the micro-etching solution treatment step of this embodiment is implemented as follows: a copper-clad board and an anti-Galvani test board are prepared and processed through the following process: Degreasing - water washing - micro-etching - water washing - OSP pre-immersion - water washing - main tank - water washing - drying.

[0027] The acidic degreasing agent CA-406C produced by Nantong Qunan Electronic Materials Co., Ltd. is used for degreasing, the operating temperature is 40°C, and the processing time is 1 minute; the micro-etching liquid of the present invention is used for micro-etching, the operating temperature is 30°C, the processing time is 1 minute, and the micro-etching amount is 0.8-1.0μm; the PCD produced by Shikoku of Japan is used for OSP pre-preg, the operating temperature is 30°C, the processing time is 0.5 minute, the A3 produced by Shikoku of Japan is used for OSP main tank, the temperature is 40°C, and the thickness of the OSP film is 0.25-0.40μm.

[0028] The above process can be carried out by horizontal spraying or vertical immersion. The copper clad laminate is used to compare the appearance of the copper surface after micro-etching treatment of the embodiment of the present invention and the comparative example to see if it is bright and clean. The anti-Giallan test board is used to compare the copper diameter loss ratio. The smaller the loss, the stronger the anti-Giallan. The appearance of the copper surface after OSP treatment is observed to see if there is "coloring" or "flowering". The film thickness after the micro-etching solution treatment of the embodiment of the present invention and the comparative example and then OSP treatment is compared. The anti-Giallan test board is a test board designed by the laboratory. The gold-copper connection method is selected, and the gold-copper ratio is 1:300 (such as Figure 1 ).

[0029] The copper diameter loss ratio of the anti-Jiafan is calculated as follows (e.g. Figure 2 ): Copper diameter loss ratio = (copper diameter before micro-etching - copper diameter after micro-etching) / copper diameter before micro-etching * 100 Table 1: Performance comparison chart name Anti-Giallian copper diameter loss ratio Film thickness Example 1 0.98% 0.35 Example 2 1.02% 0.35 Comparative Example 5.21% 0.31 Comparative Example 15.12% 0.30 The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions should also be deemed to fall within the protection scope of the technical solution of the present invention.

Claims

1. A phosphorus-free, galvanne-resistant, OSP pre-treatment micro-etching solution, characterized in that: The invention comprises the following components: 10-300 g / L hydrogen peroxide, 0-150 g / L sulfuric acid, 0.1-10 g / L hydrogen peroxide stabilizer, 1-50 g / L organic acid, 0.1-20 g / L etching rate stabilizer, 0.1-10 g / L organic base, and the solvent is water.

2. The phosphorus-free, galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The hydrogen peroxide has a concentration of 35% and is controlled between 60-150 g / L.

3. The phosphorus-free, galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The amount of sulfuric acid added is 0-8 g / L.

4. The phosphorus-free, galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The hydrogen peroxide stabilizer is one or more of amide substances, or one or more of benzenesulfonic acid substances.

5. The phosphorus-free and galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The organic acid is one or more of carboxylic acids, or one or more of sulfonic acids.

6. The phosphorus-free and galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The etching rate stabilizer includes one or more alcohol ether substances.

7. The phosphorus-free and galvanne-resistant OSP pre-treatment micro-etching solution according to claim 1, characterized in that: The organic base includes one or more of cyclohexylamine, dihydroxyethylcyclohexylamine, ethanolamine, diethanolamine and triethanolamine.

8. A PCB production process comprising a treatment step using the micro-etching solution of claim 1, characterized in that: The process is carried out through the following steps: Degreasing - water washing - micro etching - water washing - OSP pre-immersion - water washing - OSP main tank - water washing - drying; The degreasing step uses an acidic degreasing agent CA-406C, the operating temperature is 40°C, and the processing time is 1 minute; The micro-etching step uses the above-mentioned micro-etching solution, the operating temperature is 30 ° C, the processing time is 1 minute, the micro-etching amount is 0.8-1.0μm; The OSP prepreg adopts PCD, the operating temperature is 30°C, and the processing time is 0.5 minutes; The OSP main tank adopts A3, the temperature is 40°C, and the thickness of the OSP film is 0.25-0.40μm; The above steps are performed by horizontal spraying or vertical immersion.

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