Wet process with PCB surface treatment

- Nov 03, 2018-

PCB online:

1, Abrasives abrasive, brush material

To clean before the board face and brush copper surface grinding all kinds of used materials, such as polymer nonwoven fabric, nonwoven or mixed with silicon carbide, or the sand of various materials, free and Pumice (Pumice Slurry) are referred to as Abrasives.However, this incorporation of sand coated brush material, its powder often imbedded on the copper surface, resulting in subsequent photoresist or electroplating adhesion and soldering problems.The attached figure is the indication of the brush fiber mixed with sand.

2. Air Knife

At the outlet of various process line units, the blade with high temperature and high pressure air is often used to blow out the air knife, which can quickly dry the board surface to facilitate carrying and reduce the chance of oxidation.

3. Anti-foaming Agent

In the washing process of PCB process such as dry film developing liquid, the amount of organic film material is dissolved and air is mixed in the operation of extraction and spraying, resulting in the amount of foam, which is very inconvenient to the process.Chemicals that reduce surface tension, such as Octyl Alcohol or Silicone, should be added to the tank to reduce the difficulty of on-site operation.However, silicon resin containing siloxane cationic interface active agent should not be used for metal surface treatment.Once contact with the copper surface will not be easy to wash, resulting in poor adhesion of subsequent coating or soldering problems.

4. Bondability binding layer

Next layer: a surface to be joined (or followed) that must be kept clean to achieve and maintain good bonding strength.

5. Banking Agent bank protective Agent

It refers to the organic agent added in the etching solution, which makes it play a kind of skin film attachment on both sides of the line where the water is weak, so as to weaken the force of attack by the potion and reduce the degree of side etching (Cmdercut). It is an important condition for fine line etching. This agent is mostly classified by the supplier.

6. Bright-Dip luster Dip treatment

It is a kind of nibbling on the metal surface to make it more smooth and bright.

7. Chemical Milling

Is a Chemical bath wet method, all kinds of degree of corrosion of metal materials processing, such as surface coarsening, deep etching, or after applying special precision resistance agent, then such as selective corrosion, in lieu of some mechanical processing method of thrust out (Punch), also called Chemical Blanking or Photo Chemical Machining (PCM) technology, not only can save expensive mold cost and preparation time, and there was no trouble of residual stress and products.

8. Coat, Coating, surface

Usually refers to the surface of the board to do the processing layer.In broad terms, any surface treatment layer.

9. Conversion Coating Conversion

It refers to that some metal surfaces can be transformed into a protective layer of compound only by simple soaking in certain liquid groove.Phosphating treatment (Phosphating) on iron surface, Chromating treatment on zinc surface, Zincating treatment on aluminum surface, etc. can be used as the "Striking bottom" of subsequent surface treatment layer, which also can increase adhesion and enhance corrosion resistance.

10. Degreasing Degreasing

Traditionally, metal objects have been treated with "Vapor Degreasing "(Vapor Degreasing) of organic solvents, or impregnation with an emulsifying solution.But there is no need for the circuit board to be degreased, since almost no oil has been touched during all processing, which is different from metal plating.However, the pretreatment of boards still needs to use the "clean" treatment, in the concept and degreasing is not entirely the same.

11. Etch Factor Etch Factor and Etch function

In addition to direct corrosion, corrosion fluids will attack unprotected copper surfaces on both sides of the line, called Undercut, thus causing etching defects like lentinlike mushrooms. The Etch Factor is a pointer of etching quality.The term Etch Factor in the United States (mainly IPC) is the opposite of the European explanation.The American saying is the ratio of the depth of positive erosion to the concavity of lateral erosion.In Europe, by contrast, the smaller the "factor", the better.It's easy to get it wrong.However, over the years, the IPC's achievements in academic activities and publications in the circuit board industry have occupied a leading position in the world. Therefore, the definition of IPC has become a standard, and no one can replace it.

12. Etchant etching agent, etching

In the circuit board industry, it refers to the chemical tank liquid used for etching copper layers. Currently, acidic copper chloride has been used on inner plates or single plates, which has the advantage of keeping the surface of the plates clean and easy to carry out automatic management (single plates also have acid ferric chloride as etching agent).As the outer plate of double panel or multilayer board is made of tin lead, the quality of copper should be improved.

13. Etching Indicator Etching Indicator

A special wedge-shaped pattern that emphasizes whether the etching is excessive or insufficient.The specific pointer can be set on the edge of the plate to be corroded, or several plates of special etching are deliberately added in the operation batch, so as to understand and improve the etching process.

14. Etching Resist

An antietching film made on the surface of a copper conductor to protect it from corrosion, such as an image transfer pattern of electroluminescent, dry film, ink, or tin-lead coating.

15. Hard Anodizing is Hard Anodizing

Also known as the "hard anodization," refers to the pure aluminum or aluminum alloy, in anodizing cryogenic liquid (15% 15% sulfuric acid, oxalic acid, temperature under 10 ℃, freezing with lead plate, anode current density of 15 asf), for more than 1 hour of electrolytic treatment for a long time, can get 1 ~ 2 mil thick skin membrane anodized, its hardness is very high (i.e., crystalline A12O3), and can be dyed and hole sealing, is a kind of good corrosion of aluminum and decoration process.

16, Hard Chrome plating Hard chromium plating

Refers to the thick chromium coating used for wear-resistant and smooth industrial applications.Generally, decorative chromium plating can only be plated on shiny nickel surface for about 5 minutes, otherwise too long will cause cracks.Hard chromium can be hours of operation, the traditional solution components for CrO3250 g / 1 + H2SO410 %, but need to heat up to 60 ℃, low efficiency of cathode to only 10%.So other electricity will produce a lot of hydrogen gas and bring out a lot of harmful fogs made up of chromic acid and sulfuric acid, and water washing also forms a lot of yellow-brown waste water pollution.Although the cost of waste water is increased due to strict treatment, hard chromium plating is a wear-resistant coating for many quivering axles or rollers, so it cannot be completely abolished.

17. Mass Finishing a lot of whole face and a lot of polishing

Many small metal products should be carefully removed before plating, scratch and polishing surface to achieve the most perfect base, after the appearance of the best beauty and corrosion protection.Usually this pre-plating base polishing work, large objects can be done by hand with the cloth wheel machinery.But small lots of person must rely on automatic processing equipment, in general it is small and various shapes of ceramic tailor-made "polished stone" (Abrasive Media) mix, and injection of various corrosion protection solutions, with oblique slow turning mutual friction, in dozens of minutes in all parts of the surface polishing and finishing.After being poured out and separated, the Barrel can be put into another Barrel for rolling electroplating.

18. Microetching microcorrosion

It is a station in the wet process of the circuit board, in order to remove foreign contaminants on the copper surface, it is usually necessary to bite and remove the copper layer below 100 transistors -in, which is called "micro corrosion".Common microcorrosion agents are sodium persulfate (SPS) or dilute sulfuric acid plus hydrogen peroxide.In addition, in order to see the structure of each metal layer at high magnification, the polished metal section should be slightly etched to bring the truth to light.The word is sometimes called softeclues or Microstripping.

The Mouse bites the Mouse

It refers to the irregular notch on the edge of the line after etching, just like the mark after being bitten by a rat.This is an informal term that has recently become popular in the American PCB industry.

Overflow Overflow

The liquid level in the tank rises over the upper edge of the tank wall and flows out, which is called "overflow".In the water washing stations of the circuit board Wet Process, one tank is usually separated into several parts, which are washed from the dirtiest water by overflow and can be soaked for many times to save water.

21. Panel Process full-plate electroplating method

Orthodox reduction Process in circuit board (Substractive Process), which is the direct etching method to get the practice of the outer circuit, the Process is as follows: PTH - full board thick copper plating to 1 mil - feature of hole wall dry film cover hole etching - in addition to the outer plate membrane get bare copper lines. This Process is very short, positive approach without secondary copper, also don't peel plating lead tin and tin lead and indeed much easier.But the fine line is not easy to do well, and its etching process is difficult to control.

22, Passivation Passivation, Passivation treatment

A term used for surface treatment of metals, usually a stainless steel object immersed in a mixture of nitric acid and chromic acid to force the formation of a thin oxide film to further protect the substrate.In addition, an insulating layer can be formed on the surface of the semiconductor, which can insulate the surface of the transistor from electricity and chemistry and improve its performance.The formation of such surface films is also called passivation treatment.

23. Pattern Process line plating method

PTH -- > primary copper plating -- > negative image transfer -- > secondary copper plating -- > tin lead plating -- > etching -- > tin lead -- > is another approach to manufacturing circuit boards, and the Process is still the mainstream in various processes of circuit boards.It is because it is safer and less likely to go wrong.As for the longer process, the need for additional problems such as tin plating and stripping, has been a secondary consideration.

24 Puddle Effect Puddle Effect

Refers to the board in the horizontal transportation, spraying etching of the up and down movement, the panel will accumulate on the etching liquid and form a layer of water film, hinder the later spray down the Effect of etching liquid, fresh and block the instrumentality of the oxygen in the air caused by insufficient etching Effect, its corrosion speed ratio under the above board face spray to slow down some, negative Effect of the water film, and is called a Puddle Effect.

25. Reverse Current Cleaning Reverse Current (electrolysis) Cleaning

The Anodic Cleaning process is also called "Anodic Cleaning" Anodic Cleaning process.It is a common technology for surface treatment of metal.

26. Rinsing and Rinsing

In the wet process, in order to reduce the interference between the chemicals in each tank, all the intermediate sections need to be thoroughly cleaned to ensure the quality of various treatments. The washing method is called Rinsing.

Sand Blast

It is a kind of surface cleaning method by means of spraying various small particles with high speed by strong pressure.This method can remove rust on the metal, or remove difficult scaling, etc., very convenient.The sand sprayed has gold steel sand, glass sand, walnut kernel powder and so on.In the circuit board industry, Pumice is mixed with water and sprayed on the copper surface of the board for cleaning.

28, Satin Finish Satin treatment

A surface, especially a metal surface, that has been treated to achieve a luminous effect.However, this treatment is not a Mirror like full brightness situation, but a semi-gloss state.

29. Scrubber sharpener and brush sharpener

Generally speaking, it refers to the equipment that produces the brushing action on the board surface, which can perform the brushing, polishing, cleaning and other work. The brushes or grinding wheels used are made of different materials and can be carried out in a fully automatic or semi-automatic way.

Sealing hole

After anodizing the aluminum metal in dilute sulfuric acid, the "cell layer" of crystalline alumina on the surface of the aluminum had cytoplasm.After must immerse again in hot water, make alumina reabsorb a crystal water and make bulk greatens, cause cellular mouth to be squeezed small and give colour and lustre close and more durable, call Sealing.

31, Sputtering Sputtering

The cathode Sputtering Cathodic Sputtering for short, refers to the high vacuum environment and under the condition of the high voltage in the cathode metal atoms will be forced to appearance from the ontology, and formed in the environment in ionic form plasma, then ran to stay in anode processing objects, and accumulated into a layer of skin membrane, even adhere to the work surface, known as the cathode Sputtering deposition method, is a kind of metal surface treatment technology.

32, Stripper stripping fluid, stripping unit

Refers to the stripping of metal coating layer and organic leather film, or other than enameled wire skin stripping device.

33. Surface Tension of Surface Tension

A molecular attraction on the surface of a liquid that is a part of the cohesive force.This surface tension on the liquid - solid interface will prevent the liquid from spreading.For the cleaning liquid of the PCB before the wet process, the surface tension (shrinkage) force should be reduced first, so that the surface of the board and the hole wall can be easily moistened.

34, Surfactant surface moisturiser

Chemicals added to the Wetting process to reduce surface tension to assist in the Wetting action of the perforated walls of the Wetting process, also known as "Wetting Agent".

35. Ultrasonic Cleaning

An ultrasonic wave oscillating energy is applied to a cleaning solution to produce a semi-vacuum bubble (Cavitation), which USES the friction of the foam and the power of micro-stirring to cause mechanical cleansing at each corner of the object to be cleaned.

36. Keep cutting Undercutting side cutting

The original meaning of the word refers to the early artificial logging, from the roots of the tree, the ax from both sides, up and down inclined to cut the tree gradually cut off, called the Undercut.In PCB, it is used for etching process. When the plate conductor is sprayed under the cover of blocking agent, the etching liquid will theoretically attack vertically downward or upward. However, as the potion has no direction, side etching will also occur.But it is important to note that only under the ink or dry film cover, direct etching on the copper surface produced by the side of the real chip.General Pattern Process: after the second copper and tin lead are plated, when the anti-plating agent is removed and the second etching is performed, the second copper and tin lead may grow outwards from both sides. Therefore, the lateral etching part after the completion of the etching can only be aimed at the film line width, and the loss of inward etching can't be counted into the part of the coating.In addition to the defect of copper surface etching in the process of PCB manufacturing, there are similar side etching in the process of dry film development.

37. Water Break, Water Break

When the oil is cleaned very clean, a uniform film of water will be formed on the surface after being soaked to maintain good adhesion (i.e. little contact Angle) to the plate or copper surface.Generally, the water film can be kept intact for about 5-10 seconds when upright.The clean copper surface can hold for 10~30 seconds when the water film is flat.As for the dirty board surface, even if it is laid flat, it will soon appear "water break", presenting a discontinuous and separate "Dewetting" phenomenon.It is because of the adhesion between the unclean surface and the water body, which is insufficient to compete with the cohesion of the water body.This simple method of checking the cleanliness of the board is called Water Break method.

38, Wet, Wet sand Blasting

Is a kind of physical type of metal surface cleaning method, under the drive of high pressure gas, forcing mud shape of Abrasive, Abrasive) play in clean surface, used to remove dirt.The wet Pumice technology used in the circuit board manufacturing process is of this kind.

39. Wet Process Wet Process

The manufacturing process of circuit board includes dry drilling, pressing and exposure, etc.However, there are also some stations that need to be immersed in water solution, such as through holes, copper plating, and even imaging and stripping in image transfer. The latter is a Wet Process, which is called Wet Process.