PTH copper quality control method

Electroless Plating Copper is commonly known as copper. Printed circuit board hole metallization technology is one of the key manufacturing circuit board manufacturing technology. Strict control of the quality of the hole metallization is to ensure that the final product quality of the premise, and control the quality of copper layer is the key. The daily test control method is as follows:

  1. Chemical copper deposition rate determination:

The use of chemical copper plating solution, the copper rate of copper have some technical requirements. The rate is too slow may cause holes in the hole or pinhole hole; and copper copper rate is too fast, will produce rough coating. To this end, the scientific determination of copper deposition rate is one of the means to control the quality of Shen copper. To Lingling to provide the chemical thin copper coating, for example, copper deposition rate determination method:

(1) Material: Epoxy substrate after etching copper, size 100 × 100 (mm).

(2) Measuring step: A. The sample was baked at 120-140 ° C for 1 hour and then weighed using an analytical balance W1 (g); B. At 350-370 g / l of chromic anhydride and 208-228 ml / liter of sulfuric acid (Temperature 65 ℃) for 10 minutes, washed with water; C. in the chromium removal of the waste liquid (temperature 30-40 ℃) 3-5 minutes, washed; D. according to process conditions for pre-soaking , The activation of the solution, the solution in the treatment; E. in the copper liquid (temperature 25 ℃) copper for half an hour, clean; F. specimens in 120-140 ℃ bake 1 hour to constant weight, weighing W2 (g) The

(3) Sapphire rate calculation: Rate = (W2 – W1) 104 / 8.93 × 10 × 10 × 0.5 × 2 (μm)

pth copper

(4) comparison and judgment: the measurement results and technical data provided by the comparison and judgment.

  1. Method for determination of etch rate of etchant

Through the hole plating, the copper foil micro-etching treatment, so that micro-coarse, in order to increase the adhesion with the copper layer. In order to ensure the stability of the etchant and the uniformity of the etch to the copper foil, the etch rate is measured to ensure that it is within the range specified by the process.

(1) Material: 0.3mm copper clad plate, degreasing, brush plate, and cut into 100 × 100 (mm);

(2) Determination of the program: A. Sample in the hydrogen peroxide (80-100 g / l) and sulfuric acid (160-210 g / l), the temperature of 30 ℃ corrosion 2 minutes, cleaning, deionized water clean; -140 ℃ bake 1 hour, constant weight after weighing W2 (g), the sample before corrosion in accordance with this condition constant weight W1 (g).

(3) Etching rate calculation rate = (W1 – W2) 104/2 × 8.933T (μm / min)

Where: s-sample area (cm2) T-etch time (min)

(4) to determine: 1-2μm / min corrosion rate is appropriate. (1.5-5 minutes etching copper 270-540mg).

  1. Glass cloth test method

In the process of pore metallization, activation, Shen copper is the key process of electroless plating. Although qualitative, quantitative analysis of ion palladium and reducing solution can reflect the activation reduction performance, but the reliability is less than glass cloth test. In the glass cloth copper conditions the most demanding, the most can show the activation, reduction and copper copper performance. The briefing is as follows:

(1) Material: The glass cloth was pretreated in a 10% sodium hydroxide solution. And cut into 50 × 50 (mm), the end of the week to remove some of the glass, so that the glass spread out.

(2) the test steps: A. the sample according to the copper process to deal with copper;
B into the copper liquid, 10 seconds after the end of the glass cloth should be completely copper, black or dark brown, 2 minutes later All the Shen Shen, 3 minutes after the copper deepened; on the thick copper, 10 seconds after the end of the glass cloth must be completely copper,

30-40 seconds, all sink copper; C judge: If the above copper effect , Indicating that activation, reduction and Shen copper performance is good, but is bad.

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