one. Electroplating process classification:
Acid bright copper plating nickel / gold electroplating tin
Second,
the process: pickling → full plate copper plating → graphic transfer → acid degreasing → secondary counter-current rinsing → micro-etching → secondary → pickling → tin → secondary counter-current rinsing
Countercurrent rinsing → pickling → graphic copper electroplating → secondary countercurrent rinsing → nickel plating → secondary washing → citric acid leaching → gold plating → recycling → 2-3 grade pure water washing → drying
Three. Process description:
(A) pickling acid
① role and purpose: remove the surface oxides, activation of the board, the general concentration of 5%, and some remain at about 10%, mainly to prevent water brought into the bath sulfuric acid content instability; acid leaching time should not be too long , To prevent oxidation of the board; in use for a period of time, the acid cloudy or copper content is too high should be promptly replaced, to prevent contamination of the surface of the copper plating and plate;
③ here should be used CP grade sulfuric acid;
(B) the whole board Plating copper: also known as a copper, plate, Panel-plating
① role and purpose: to protect the just deposited thin chemical copper, chemical oxidation of copper to prevent corrosion after being removed by electroplating it to a certain extent
② full-board copper plating process parameters: the main components of copper sulfate bath and sulfuric acid, the use of high-acid low-copper formula to ensure uniformity of plate thickness distribution and plating deep hole deep plating capacity; sulfuric acid content and more In the 180 g / L, more than 240 g / L; copper sulfate content is generally about 75 g / L, the other bath was added a trace amount of chloride ions, as an auxiliary gloss and copper agent together play a gloss effect; copper The amount of light agent or the amount of open cylinder is generally 3-5ml / L, the addition of copper agent generally in accordance with the method of thousands of hours to supplement or according to the actual production board effect; the whole board plating current calculation generally 2A / square Multiply the board can be plated on the area, for the whole board is concerned, that plate length dm × width dm × 2 × 2A / DM2; copper cylinder temperature maintained at room temperature, the general temperature does not exceed 32 degrees, and more control At 22 degrees, so in the summer due to the temperature is too high, the copper cylinder is recommended to install cooling temperature control system;
③ process maintenance:
according to thousands of hours every day to replenish the copper agent, added by 100-150ml / KAH; check the filter pump is working properly, with or without leakage phenomenon; every 2-3 hours, apply a clean wet cloth The cathode conductive rod scrub clean; regular weekly analysis of copper copper sulfate (1 / week), sulfuric acid (1 / week), chloride (2 times / week) content, and through the Hall tank test to adjust the light Agent content, and timely replenishment of related raw materials; Weekly to clean the anode conductive rod, the tank ends of the electrical connector, and promptly replenished the anode basket titanium ball, with a low current 0.2-0.5ASD electrolysis 6-8 hours; Should be checked every month on the anode titanium basket is damaged, damaged should be promptly replaced; and check the bottom of the anode titanium basket is deposited with anode mud, if timely cleaning should be clean; and carbon core continuous filtration 6-8 hours, while low Current electrolysis impurity; every six months or so specific according to the tank liquid pollution status decide whether the need for large processing (activated carbon powder); every two weeks to replace the filter pump filter;
④ large processing procedures:
- Remove the anode, the anode poured out, wash the anode surface anode film, and then placed in a barrel copper anode, with a micro-etchant roughening copper surface to a uniform pink, washed with water After loading into the titanium basket, side into the acid tank spare B. The anode titanium basket and anode bag into 10% alkali soak 6-8 hours, washed with water, then dilute with 5% sulfuric acid, washed with water C, the transfer of the bath to the spare tank, adding 1-3ml / L of 30% hydrogen peroxide, began to heat until the temperature is increased to about 65 degrees open the air stirring, holding air stirring 2-4 hours; D Turn off the air mixing, 3-5 grams / liter slowly dissolve the activated carbon into the bath solution, to be dissolved thoroughly, turn on the air stirring, so heat 2-4 hours; E turn off the air mixing, heating, So that the active carbon slowly precipitated to the bottom of the tank; F until the temperature dropped to about 40 degrees, with 10um PP filter plus help filter filter tank to clean the work tank, open the air mixing, into the anode, hanging Into the electrolysis board, according to 0.2-0.5ASD current density of low current electrolysis 6-8 hours, G. by laboratory analysis, adjust the sulfuric acid tank Copper sulfate, chloride ion content to the normal operating range; according to Hall channel test results to add light agent ;. H to be electrolysis board surface uniform color, you can stop electrolysis, and then by 1-1.5ASD current density of electrolysis Immersion film processing 1-2 hours, until the anode to generate a layer of uniform and dense adhesion of black phosphorus can be good;
⑤ anode copper ball contains 0.3-0.6% of the phosphorus, the main purpose is to reduce the anode dissolution efficiency and reduce the production of copper powder;
⑥ supplement drugs, such as larger amount of added, such as copper sulfate, sulfuric acid; after adding low-current electrolysis What should be paid attention to safety when supplemented sulfuric acid, when the additional amount is larger (more than 10 liters) should be added slowly in several times; otherwise it will cause the bath temperature is too high, light decomposition speed up, pollute the bath;
⑦ chloride Of the additional should pay special attention to, because the chloride ion content is particularly low (30-90ppm), additional must be used when the measuring cylinder or measuring cup can be accurately added before; 1ml hydrochloric acid chloride ions about 385ppm,
⑧ The formula of adding medicine:
Copper sulfate (kg) = (75-X) × tank volume (liter) / 1000
sulfuric acid (unit: liter) = (10% -X) g / L × tank volume (Unit: liter)
or= (180-X) g / L Slot volume (liter) / 1840
(C) Acid degreasing
① purpose and purpose: remove the copper lines on the surface oxide, residual ink residue film to ensure that a copper and copper or nickel plating graphic binding force
② Remember where to use acid degreasing agent, why not alkaline Degreasing agents and alkaline degreasing agent degreasing effect is better than acid Degreasing agent mainly because the graphics ink is not alkali-resistant, will damage the graphics lines, so the graphics can only be used before plating acid degreasing agent.
③ only need to control the degreasing agent concentration and time of production, degreasing agent concentration of about 10%, time to ensure that in 6 minutes, the longer the time will not have an adverse effect; bath replacement is also in accordance with 15 square meters / liter work Liquid, add in accordance with 100 square meters 0.5-0.8L;
(D) micro-corrosion:
① purpose and role: clean roughening copper lines to ensure the binding between the copper plating and the primary copper
② micro-etchant more sodium persulfate, the roughening rate of stable uniform, washed well , The concentration of sodium persulfate is generally controlled at 60 g / l or so, the time control in about 20 seconds, drugs added by 100 square meters 3-4 kg; copper content controlled at 20 g / l or less; eclipse.
(E) pickling acid
① purpose and purpose: to remove the surface oxides, activation of the board, the general concentration of 5%, and some remained at about 10%, mainly to prevent water brought into the bath sulfuric acid content instability; acid The immersion time should not be too long, to prevent oxidation of the board; in use for a period of time, the acid cloudy or copper content is too high should be replaced in time to prevent the pollution of copper plating and plate surface;
③ here should be used CP grade sulfuric acid;
(F) Graphical copper plating: also known as secondary copper, copper circuit
① purpose and role: in order to meet the rated current load of each line, the copper and copper lines need to reach a certain thickness, the purpose of copper plating lines Hole copper and copper line thickening to a certain thickness;
② other projects are the same plate plating
