Printed circuit board and method for processing surface of printed circuit board

A printed circuit board and surface treatment technology, applied in the directions of printed circuit, printed circuit manufacturing, electrical components, etc., can solve the problems of difficult control, affecting the reliability of lead-free solder solder joints, solder joint failure, etc., to reduce process links, The appearance is white and bright, not easy to fatigue and creep effect

Inactive Publication Date: 2013-11-06
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, due to the difficulty in controlling the gold-based processing process, there are problems such as black disks, and the gold layer is generally thin. After soldering the lead-free solder and the nickel-based thin film metal layer, it is easy to form Ni at the interface. 3 The P (nickel-phosphorus) layer can also cause solder joints to fail under cyclic heat, electricity, and mechanical action, thereby affecting the reliability of lead-free solder joints

Method used

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  • Printed circuit board and method for processing surface of printed circuit board
  • Printed circuit board and method for processing surface of printed circuit board
  • Printed circuit board and method for processing surface of printed circuit board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] see figure 2 , a PCB surface treatment method for semiconductor packaging comprising the steps of:

[0043] (1) Apply solder resist on the area other than the circular Cu pad 36 on the PCB substrate 31 that needs surface treatment, including the output wire 35, and dry it to form a solder resist area 33, and evenly coat the surface of the solder resist area 33 with Cover a layer of anti-plating film 34, and cover the peripheral area that does not need electroplating with adhesive tape 32 after the input / output ends of the wires are connected; use ultrasonic cleaning to form the PCB substrate 31 with the above-mentioned anti-plating agent / adhesive tape and dry, wherein, the Cu welding The disc 36 has a diameter of 0.5 mm;

[0044] (2) Put the cleaned PCB into the plasma cleaning equipment for micro-etching for 3 minutes. The working gas is a mixed gas of argon and air. The flow rate of the working gas is 10SCCM and the power is 0.2KW. 0.9 Pa;

[0045] (3) The cobalt-...

Embodiment 2

[0051] see figure 2 , a PCB surface treatment method for semiconductor packaging comprising the steps of:

[0052] (1) Same as embodiment 1;

[0053] (2) Same as Example 1, wherein the micro-etching treatment time is 4 minutes, the flow rate of the working gas is 9SCCM, the power is 0.3KW, and the pressure in the cavity is kept at 0.8 Pa by a vacuum pump;

[0054] (3) Electroplating is used to form a cobalt-based metal layer 37 on the surface of the PCB. The anode used for electroplating is a cobalt sheet, the cathode is a circular Cu pad on the PCB, and the electroplating solution is composed of CoCl with a concentration of 0.15mol / L. 2·6H 2 O, CoCO at a concentration of 0.095mol / L 3 , the concentration is 0.35mol / L of H 3 PO 4 , the concentration is 0.15mol / L of H 3 PO 3 , the concentration is 0.02 g / L sodium saccharin, the temperature is 75°C, and the current density is 3.5A / dm 2 , the coating time is 8min, and ultrasonic assisted deposition is applied;

[0055] (...

Embodiment 3

[0060] A method for surface treatment of an IC mounting surface substrate for packaging is obtained as image 3 Shown is a packaged IC mounting surface substrate formed with a cobalt-based metal layer. The surface treatment method comprises the following steps:

[0061] (1) Apply solder resist on the area of ​​the IC mounting surface substrate 41 that requires surface treatment other than the surface mount Cu pad 44 and dry to form a solder resist area 42, and evenly coat a layer of anti-solder on the surface of the solder resist area 42. The coating 43 is finally cleaned and dried with ultrasonic water, wherein the diameter of the Cu pad 36 is 0.5 mm;

[0062] (2) Put the cleaned PCB into the plasma cleaning equipment for micro-etching for 8 minutes. The working gas is a mixed gas of argon and air, the flow rate is 5SCCM, the power is 0.4KW, and the pressure in the cavity is kept at 1 Pa by a vacuum pump;

[0063] (3) After activating the IC mounting surface substrate with ...

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Abstract

The invention discloses a method for processing the surface of a printed circuit board. The method comprises the steps that the printed circuit board is provided, the printed circuit board comprises a printed circuit board substrate and a brazing disc formed on the printed circuit board substrate, welding resistance processing and anti-plating processing are conducted on zones outside the brazing disc on the printed circuit board substrate; micro-etching is conducted on the brazing disc; a cobalt-based metal layer is formed on the surface of the brazing disc which undergoes micro-etching and the cobalt-based metal layer is used for directly making contact with lead-free solder, and the printed circuit board with the cobalt-based metal layer is cleaned and dried. The invention further provides the printed circuit board which undergoes the processes.

Description

technical field [0001] The invention relates to a method for surface treatment of a printed circuit board (PCB) used for packaging in the field of microelectronic packaging. Background technique [0002] In the field of microelectronic packaging, the pads or terminal parts on the PCB, the component holes for inserting components, and the printed contact piece parts are not only used for soldering, but also for component connections such as wire bonding and contact leads with connectors. Pass. Therefore, various treatments to ensure the solderability, connection reliability and contact reliability of this part of copper are called final finish or surface finish. [0003] There are mainly four methods for the surface treatment of existing PCBs, namely organic solder film treatment, tin-based treatment, gold-based treatment (electroless nickel plating / immersion gold) and electroplating silver. Among them, gold-based treatment is the most widely used PCB surface treatment meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05K3/00
Inventor 李亮亮杨栋华蔡坚王谦
Owner TSINGHUA UNIV
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