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PCB manufacturer: selective surface treatment process
2021-09-24
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Author:Aure

PCB manufacturer: selective surface treatment process



1. Shen Xi

 A. Tin thickness standard: 0.8-1.2um;

 B. Process flow:

Pre-process → solder mask → character → electrical test → (second drill) → milling → final inspection → sinking tin → final inspection → packaging

C. Matters needing attention:

(1) Immersion tin board is not allowed to be directly pickled before tin sinking. If it is due to abnormal board surface oxidation, the problem board must be degreasing, water washing, micro-etching, and water washing on the immersion gold line (parameters follow the line process Standard implementation), and then washed and dried on the finished product washing machine.

(2) The packaging is separated with clean white paper from time to time, and then vacuum-packed.

2. Shen Yin

  A. Silver thickness standard: 0.1-0.3um

B. Process flow:

Pre-process → solder mask → character → electrical test → (second drill) → milling → final inspection → heavy silver → final inspection → packaging

C. Precautions: Separate the packaging with clean white sulfur-free paper, and then vacuum packaging. It is forbidden to place moisture-proof beads to avoid yellowing of the silver surface.



PCB manufacturer: selective surface treatment process


3. OSP

A. OSP thickness standard: 0.3-0.6um

B. Process flow:

Pre-process → solder mask → character → electrical test → (second drill) → milling → final inspection → OSP → final inspection → packaging

C. Matters needing attention: It is forbidden to over-acid treatment or bake the board of the finished OSP.

4. The whole board is plated with hard gold

A. Hard gold thickness standard: nickel thickness control 3-5um; gold thickness control 0.25-1.3um;

When the customer has the requirement of not electroplating nickel, the nickel thickness is controlled as 0um;

    B. Process flow:

Drilling → sinking copper → plate plating → external light imaging → pattern plating → hard gold plating → outer layer etching → next step

C. Matters needing attention:

ERP indicates that W-250 dry film is used for external light imaging; the figure plating only thickens copper without tin plating; the thickness of nickel and gold plating is required.

5. Immersion gold + spray tin

A. The process flow of using red tape: solder mask→immersion gold→spray tin→next process

B. The process flow of using blue glue: solder mask→immersion gold→blue glue→spray tin→next process

C. Matters needing attention:

(1) The process of using red tape: ERP indicates that the red tape should be used to stick the gold part before spraying.

(2) The process of using blue glue: prepare the corresponding tools for the project.

(3) For through-holes, the treatment process on both sides must be the same.

6. Water gold + tin spraying (process A is the first choice for this process, followed by process B)

A. The process flow of using red tape:

Pre-process → picture plating → full board water gold → outer layer etching → outer layer AOI → solder mask → characters → tin spraying → next process

B. The process flow of using blue glue:

Pre-process → picture plating → full board water gold → outer layer etching → outer layer AOI → solder mask → characters → blue glue → spray tin → next process

C. Matters needing attention:

(1) The process of using red tape: ERP indicates that the water and gold parts need to be pasted with red tape before spraying tin.

(2) The process of using blue glue: prepare the corresponding tools for the project.

(3) For through-holes, the treatment process on both sides must be the same.

7. Immersion gold + gold finger

 A. Gold finger thickness standard: nickel thickness control 3-5um; gold thickness control 0.25-1.0um

   B. Process flow: previous process solder mask→character→immersion gold→gold-plated finger→next process

D. Matters needing attention: ERP indicates that if the gold finger thickness requirement is greater than 1.0um, red tape must be used before the gold is required.

The gold-plated fingers are partially attached to the gold, and then the gold-plated fingers are released.

8. Water gold + gold finger

  Process flow:

  Plate plating→external light imaging 1→picture nickel-plated gold→external light imaging 2→hard gold plating (gold-plated fingers)→etching

  Precautions:

(1) ERP indicates: The dry film used for the second time of external light imaging is W-250; the film does not fall after nickel and gold plating; the hard gold plating is only gold plating; and the corresponding nickel and gold thickness requirements.

(2) Outside line film production: outside light imaging 2 line window is 0.5MIL larger than outside light imaging 1 line on each side, and the minimum line distance after compensation is 4MIL;

(3) In the drilling program, the 4 corners of the board will increase the alignment hole used for the external light imaging 2 alignment. The aperture is required to be 0.70mm, and the external light imaging 2 is developed, and the pad and the hole are the same size.

9. Immersion gold + OSP

   Process flow:

   A. Full-board OSP after full-board immersion gold:

Solder mask→character→immersion gold→electrical test→(second drill)→milling→final inspection→OSP→final inspection→package

  B. Optional Immersion Gold and OSP:

Solder mask→characters→external light imaging→immersion gold→fading film→electrical test→(second drill)→milling→final inspection→OSP→final inspection→packaging

C. Matters needing attention:

(1) Engineering film production: open the window for the part that needs heavy gold, and cover the OSP part with dry film. In addition, the large area of the solder mask can also be opened with square windows (5*5MM), and the distance between the square windows is 30-40MM. In order to fade the film after immersion gold.

(2) Use of dry film: ERP indicates that the model of dry film used is W-250.

 10. Carbon oil + sinking gold

Process flow: solder mask→character→immersion gold→carbon oil→next process

Note: The board surface before silk-screening carbon oil does not need to undergo any treatment, just silk-printing carbon oil directly. It is forbidden to use acid or alkali to touch the gold surface before and after the carbon oil, so as to avoid the golden color or the carbon oil.

 11. Carbon oil + tin spray

Process flow: solder mask → character → carbon oil → spray tin → next procedure

 12. Carbon oil + OSP

Process flow:

Solder mask→character→carbon oil→electrical test→(second drill)→milling→final inspection→OSP→final inspection→package

  13, OSP + gold-plated fingers

 Process flow:

Solder mask→characters→gold-plated fingers→(second drill)→milling→electrical test→final inspection→OSP→final inspection→package

      Note: The board that passes through OSP is prohibited from contacting acidic substances or baking boards.

  14. Immersion silver + gold-plated fingers

 Process flow:

Solder mask→characters→gold-plated fingers→(second drill)→milling→electrical test→final inspection→immersion silver→final inspection→package

Note: Cover the golden fingers with red tape before immersing the silver.

  15. Immersion tin + gold-plated fingers: (now can not be made in the factory, you need to suggest the customer to change. Lxf2005.10.14)

Process flow:

Solder mask→characters→gold-plated fingers→(second drill)→milling→electrical test→final inspection→sinking→final inspection→package

Note: Cover the golden fingers with red tape before sinking the tin.

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