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Ferric chloride etching fluid, and other etching s

2010 May 24
Posted by tamay

ferric chloride etching fluid

in the printed circuit, electronic and metal finishing industries in the extensive use of ferric chloride etching of copper, copper alloy and iron, zinc and aluminum. Then the process because of its stability, easy, cheap. However, in recent years, due to its regeneration difficulties, pollution, waste processing difficulties which are being phased out. Thus, there is only a brief introduction.

ferric chloride etching solution for printed materials in the screen printing resists, liquid photoresist, dry film, and gold etching resist layer of the PCB. But not for nickel, tin, tin – lead alloy corrosion layer.

1. etching the main chemical reaction

ferric chloride etching solution is an etching on the copper oxidation – reduction process. Fe3 + in the copper surface oxidation of copper chloride. While Fe3 + is reduced to Fe2 +. FeCl3 + Cu → FeCl2 + CuCl

CuCl is reducing, can be produced by the reaction FeCl3 further copper chloride.

FeCl3 + CuCl → FeCl2 + CuCl2

Cu2 + with the oxidation, and oxidation of copper occurs:

CuCl2 + Cu → 2CuCl

Therefore, FeCl3 etching solution on the etching Cu When Fe3 + and Cu2 + by co-complete. In which the etching rate of Fe3 + fast, etching good quality; and Cu2 + in etch rate is slower and poor quality etch. Newly prepared etching solution, only Fe3 +, so fast etching rate. However, with the etching reaction to, Fe3 + continuously consumed while the Cu2 + on the rise. When Fe3 + consumes 35%, Cu2 + has been increased to a considerable concentration, when Fe3 + and Cu2 + on the Cu etching amount almost equal; when Fe3 + consumes 50%, Cu2 + of etching from the back seat and jumped the main position, this time slower etching rate, etching solution should be considered an update.

in the actual production, said etching solution is not to use the activity to measure the consumption of Fe3 +, but with the etching solution in the copper content (g / l) to measure. Because the copper etching process, the first etching time is relatively constant. However, with the Fe3 + consumption, increasing copper content in solution. When the dissolved copper reached 60g / l, the etching time will be extended, when the etching solution of Fe3 + consumption of 40%, the dissolved copper reached 82.40g / 1, the etching time will be dramatically increased, indicating that the etching solution can not now continue to use, consider the regeneration of etching solution or update.

little of general plants and determination of copper content in the etching solution, etching time and etching mostly to determine the quality of etching solution regeneration and renewal. Experience data, dynamic etching, the temperature is around 500C, copper thickness of 50μm, the best etching time of 5 minutes, 8 minutes, can still be used, if more than 10 minutes, severe side etching, etching quality deterioration, should be considered etching solution regeneration or update.

etched copper foil, it is also accompanied by some side effects, that is, the hydrolysis of CuCl2 and FeCl3:

FeCl3 +3 H2O → Fe (OH) 3 ↓ +3 HCl

CuCl2 +2 H2O → Cu (OH) 2 ↓ +2 HCl

generated hydroxide is unstable and easily decompose after heating:

2Fe (OH) 3 → Fe2O3 ↓ +3 H2O

Cu ( OH) 2 → CuO ↓ + H2O

results generated red iron oxide and copper oxide black particles suspended in the etching solution on the corrosion layer has some damaging effects.

2. the factors affecting the etching rate

> Fe3 + concentration and temperature of etching solution etching solution

higher the temperature, the faster the etching rate, the temperature should be chosen order not to damage the resist layer on the principle, generally 40 ~ 50 ℃ suitable.

Fe3 + concentration on etching rate are greatly affected. Fe3 + concentration in etching solution gradually increased, corresponding to speed up the etching rate of copper. When Fe3 + contained more than a certain concentration, due to increased viscosity, but the etching rate decreased. General etching resist coating printing screen printing materials, dry film of the PCB, the concentration can be controlled in 350Be ‘around; etching coated liquid photoresist (such as bone glue, polyvinyl alcohol, etc.) of the PCB concentration will have to control 420Be ‘above. The weight percentage of the relationship between concentration and proportion shown in Table 10-5:

Table 10-5 ferric chloride solution, the composition of the low concentration

optimal concentration

high concentration

concentration (g / l)

365

452 530

608

weight concentration

28

34 38

42

proportion

1.275

1.353 1.402

1.450

Baume degrees

31.5

38 42

45

>

addition of hydrochloric acid in etching solution by adding hydrochloric acid, can inhibit the hydrolysis of FeCl3, and enhance the etching rate. Especially when the dissolved copper reached 37.4g / l, the hydrochloric acid is more obvious. However, the addition of hydrochloric acid to the appropriate acidity is too high will cause the liquid photoresist (such as bone glue, polyvinyl alcohol, etc.) coated with a low acidity of the solution PCB only.

> etching fluid mixing

static etching efficiency and quality is poor. This is because the etching process at surfaces and in solution will precipitate, Ershi solution was dark green, the precipitation will affect the further etching.

using air agitation, spray or splashing operation can speed up the etching reaction. Etching rate of increase is part of the Fe2 + and Cu1 + re-oxidized to Fe3 + and Cu2 +.

4Fe2 + + O2 +4 H + → 4Fe3 + +2 H2O

4Cu1 + + O2 +4 H + → 4Cu2 + +2 H2O

other etching solution

> sulfuric acid – chromic acid etching solution

corrosion on tin-lead alloy plating layer with good PCB etching effect. However, chromate is “three wastes” in the subject country ranked first harmful substances are harmful to people and animals and plants. Therefore, it is now almost not to etch PCB.

> ammonium persulfate etchant

apply to printed materials using screen printing resists, dry film, and gold for corrosion layer PCB. However, its ability to etch rate and dissolved copper chloride etching solution is not as high, easy to decompose, coupled with high costs, are generally used for graphics before the copper plating micro-etched surface.

> sulfuric acid – hydrogen peroxide etching solution can be used for graphics

micro etching treatment before plating. In recent years begun for PCB etching. It features non-corroding tin-lead alloy, the solution is very simple components, the product only after etching copper sulfate. After etching liquid can be recycled and recycling, high purity copper sulfate crystals. Therefore significantly reduce waste emissions and environmental pollution, is promising etching solution.

carved speed 度 slow?

You see the need to explore the way that the outside or the remote, basically carved rate is representative of slow activity as long as 率 降 low 了.

You need to first check the reasons for the low activity of 降, 例 such as: outside the carved through 量 is sufficient? The liquid oxidation was originally carved

not normal? Micro-liquid or liquid containing 量 離 度 whether such bias, these are all possible reasons. You must be some fundamental

do home to solution.

factors affect the characteristics of etching solution

PCBTech.Net :2005-06-25 19:19 Source: China PCB Forum Network hit: 1579 times

1, physical and chemical aspects of 1, the concentration of etching solution should be based on metal corrosion principles and the structure of the type of copper foil, determined by test concentration, it should be given more choice. 2, etching liquid composition of the chemical composition, chemical composition is different, the etching rate is not the same etching factor is different, usually acidic copper chloride etching factor of 3; the basic copper chloride, up to 3.5-4.

1, Physics and chemistry

1, the concentration of etching solution should be based on copper metal corrosion principles and the structure of the type, concentration determined by experiment, it should be given more choice.

2, etching liquid composition of the chemical composition, chemical composition is different, the etching rate is not the same coefficient of different etching, acid etching coefficient of copper chloride is usually 3; the basic copper chloride can be up to 3.5-4. In the development stage of nitrate-based etching solution can achieve little side corrosion problems, wires close to the vertical wall.

3, the temperature of the etching solution properties of relatively large, the temperature of the solution to accelerate the flow of etching solution and reduce the viscosity and improve the etching rate plays a very important role, but the temperature is too high, easy to chemical composition caused by evaporation, causing the chemical imbalance can cause destruction of polymer resist layer and influence the lifetime of equipment.

4, used in copper clad thickness: thick copper wire density on the circuit graph has an important impact, thin copper foil, etching time is short, lateral erosion was very small, whereas the lateral erosion on the lot. Therefore, the circuit must design and graphics precision wire density and wire to choose copper foil thickness, while the elongation of copper, fine grain structure, will constitute the direct effects of etching fluid properties.

5, the geometry of the circuit: the circuit graph leads the direction and Y direction in the X position if the distribution is not balanced, will directly affect the etching solution on the plate of the flow velocity, as if in the same plate surface narrow interval location and width of the conductor wire part of the state, the interval width of the wire distribution of parts, etching will be over, so, requiring designers to design the circuit, we should first understand the process viability, as do the entire circuit board graphics uniform distribution, the thickness of wire should be consistent with the degree, especially in the production of multi-layer printed circuit board, a large area of copper foil as the ground layer, the quality of the etching has a great influence, it is proposed designed to mesh graphics suitable.

6, device type: device structure is also characteristic of etching solution to one of the factors students,Protection film, the level of mechanical transmission structure of the etching equipment used swing nozzle, so that the copper lines etched surface more uniform, But the board too easily lead to erosion, therefore, research and development of a vertical spray technology, while devices also shall prevent the thin copper foil laminated board in the etching and transmission easy winding wheel in the wheel and cause waste of equipment, and scratches the surface of metal is not guaranteed or scratches.

2, spray technology

1, spray shape: the current sprinkler system should have the common conditions and structure, is the leaching system in the fountain to take chain, the cone structure, all out of the etching liquid jet nozzle is sector and exchange so that all transmission fluid all cover plates are etched, but also uniform flow, multi-technology test results show that:

* fixed type of spray: Average etch depth: 0.2MM. Standard deviation of 0.01MM.

* Swing the spray: the average etching concentration: 0.21MM. Standard deviation 0.004MM.

2, swing way: through the actual production of product experience has shown that the ideal swing arc, etching liquid can reach the entire board, improve the consistency of the etching rate.

3, distance: mean distance from the nozzle to the plate surface is liquid etching cream fountain to the distance between the substrate surface, which is very important, must also meet the economic, applicability, manufacturability, can be Maintenance and Replacement of.

4, pressure: to take into account in the design of pressure on the liquid spray etching effect on the substrate surface, etching the ability to form a uniform liquid flow and the balance of flows, so pressure is too large or too small will result in the quality of etching

etching process should pay attention

PCBTech.Net :2005-04-27 17:14 Source: China PCB Forum Network hit: 1113 times

1. to reduce conflicts along the lateral erosion and improve the etching factor side of cavitation conflict along. PCB in the etching solution is usually longer, more serious side erosion. Lateral erosion seriously affect the accuracy of printed conductors, will produce severe side etching fine line impossible. When erosion and conflict along the lower side, the etching factor on the rise, a high etching factor that has the ability to maintain fine wire to wire close to the original image after etching

1. to reduce conflicts along the lateral erosion and improve the etching produce sudden loss coefficient along the side. PCB in the etching solution is usually longer, more serious side erosion. Lateral erosion seriously affect the accuracy of printed conductors, will produce serious side etching fine line impossible. When erosion and conflict along the lower side, the etching

coefficient on the rise, a high etching factor that has the ability to maintain fine wire to wire close to the original image after etching size. Both etching resist plating tin – lead alloy, tin, tin – nickel alloy or nickel, will cause conflicts along the over-

wire short circuit. Because the conflict along the easy break down and two points in the wire between the power of the bridge.

lateral erosion of the factors that affect a lot of points are summarized below:

1) etching method: immersion and Bubble will result in a large etching lateral erosion, splash and spray etching smaller lateral erosion, especially in spray etching the best.

2) the type of etching liquid: a different chemical composition of different etching solution, the etching rate on the different etching factor is also different. For example: acid etched copper chloride etching solution coefficient usually 3, alkaline copper chloride etching solution etching coefficient reached 4. Recent studies show that nitrate-based etching system can do little side corrosion, etching lines up close to the vertical wall. This etching system is yet to be developed.

3) etching rate: slow etching rate may result in serious side of the eclipse. Improving the quality of etching and the etching rate has a lot to speed up. Etching faster board in etching fluid shorter stay, the less amount of side etching, etching out the graphics clear and neat.

4) etching liquid PH value: alkaline etching liquid PH value is high, the lateral erosion increases. In order to reduce lateral erosion, generally in the 8.5 PH value should control the following.

5) etching fluid density: alkaline etching fluid is too low will increase the density of lateral erosion, use of high copper concentration of etching solution to reduce the side etching is beneficial.

6) Copper thickness: lateral erosion to minimize the etching of fine wire, preferably with (ultra) thin copper foil. And finer line width, copper thickness should be thinner. Because the thinner copper etching solution in less time, the smaller the amount of lateral erosion.

2.

board and the board to improve the consistency between the etching rate in continuous board etching, the etching rate of the more consistent, more uniform etching of the board can get. To meet this requirement, must ensure that etching in the etching solution is always to keep the whole process of etching in the best state. This requires selection of easy

regeneration and compensation, easy to control the etching rate of etching solution. Selected to provide a constant operating conditions and parameters can automatically control the various solution techniques and equipment. By controlling the dissolved copper content, PH value, the solution concentration, temperature, solution flow uniformity (spray nozzles and nozzle systems or swing), etc. to achieve.

3.

high etching rate of the entire board surface, the uniformity of the upper and lower sides of the board and the board surface etching uniformity in all parts of the surface by the board subject to the uniformity of etching agent flows determined.

etching process, the upper and lower plate surface of the etching rate is often inconsistent. In general, the lower plate surface etching rate is higher than the board. Solution on the board because there is accumulation, reduced the etching reaction. Nozzle can be adjusted up and down

the spray pressure to resolve the upper and lower porphyrin board uneven etching. PCB etching a common problem is in the same time made all the board are etched clean, it is difficult to do, the board than the board the center of the edge fast etching.

swing by spray nozzle systems and to be an effective measure. Further improvements can be made plate center and edge of the spray pressure plate different plates front and rear intermittent etching plate approach, the loss of the entire board

carved uniformity.

4.

improve the safe handling and etching of thin copper foil and thin plate capacity

in such a thin inner layer etching multilayer plate, the board is easy winding in the Wheel and the transmission wheel and cause waste. Therefore, the inner plate etching equipment to ensure smooth, and can * handle thin laminates. System of many devices

etching machine manufacturers in the gear or wheel attached to prevent the occurrence of such phenomena. Better approach is to use additional Teflon coated bag swinging around as a thin plate transmission line supports. The thin copper foil (for example 1 / 2 or 1 / 4 ounces) etching, to ensure that no abrasions or scratches. Thin copper foil stand up to 1 ounce copper foil as the etching time of mechanical defects, sometimes more intense vibrations are likely to scratch the copper.

5.

to reduce pollution of water pollution is a copper printed circuit common problems in production, the use of liquid ammonia alkali etching is more important this problem. Because copper and ammonia complex, not easy to use ion exchange or precipitation to remove alkali. Therefore, using the second spray

leaching method of operation, with no added copper solution to rinse the board, greatly reduce the excretion of copper. Then, the air knife in the water, then rinse the surface prior to the board to remove excess solution, thereby reducing the water on copper and etching of the salts

rinse burden.

Solder He Ying 不 綠 paint it?

are many factors that affect 不, 例 such as: video mouth plugging 塞, 露 light exposure are like, exposure , video 不 feet,

before baking for a long time, the film broke 洞, ink on and so on. Too many factors can be raw, so to make it clear whether 什

, is whether the lack of features like 什.

dry holes on the causes and improve the use of dry film

, frequent random dry holes (diameter 4.0 – 6.0), resulting in NPTH PTH hole into a hole, about the proportion of 1% -2%, I do not know which shrimp can be given to help solve this problem!!

1. Reduce the foil temperature, pressure;

2. To improve the status of drilling Phi front;

3. Increased exposure energy;

4. Reduced gold pressure, increased imaging point;

5. Check and adjust visualization of spray effects.

added:

foil before the surface temperature of the control panel, foil speed, pressure, too low, are negative; foil placed at the proper time after the board recommended 10-15 minutes;

exposed plate surface temperature should not be too high, the cooling plate surface to be faster; exposure properly, excessive exposure will dry hair brittle; exposure, and lack of strength is inadequate;

develop over: pay attention to controlling temperature, pressure, velocity, developer solution concentration;

In addition, when the plating time, plating should not be too long, including plating of copper and tin-plating!

for the inner layer is concerned, generally there are Open Or Short. To solve these problems, in fact, it is not hard

1.open major attention to a clean room environment and the drying out effect of pre-treatment, clean room environment has mainly coated with exposure room, the former may have a sticky coating dust machine Pre-test treatment effects, coated with a sticky coating machine test results page after baking, if two of the stick a lot of dirty dust machine Weblog prototypes point, then have to do cleaning and maintenance of the two. Degree of exposure of a clean room is also very important, this place is dirty spot on the gap or open circuit. When a film is best when the exposure of a clean. There is removal of scratches, light scratches before and after exposure will have a gap and open circuit.

2.Short major attention to whether the incoming side of a coil of copper plate phenomenon, and if so, this will bring under the process of making trouble, one coated round will be stabbed, 2, film can easily be scratched. Third, the vacuum will absorb bad. These three are some of the reasons may cause a short circuit.

3. residual copper key is to control the lithography and etching, and no other, developing a washing fluid cleanliness, and etching is whether the need to filter dirty

line problem Well, of course searching for answers from the line where the formation of a

gap open stubs biggest copper still short by far the most likely of which took place in the inner clean room

Speaking from the coating machine coating round the control of ink will be scratched coating caused by bad bad not to mention the line coating prerequisite for the formation of the problem is definitely not good that a lot of drop exposure exposure

then divided into two parts here, one second of film exposure

first film with the problem that most frequently is this Lifei Lin is expected to produce the most important number of retired high-volume wash with the scrap is a problem here, and out from the film to production problems on a lot of exposure machine there are line problems mainly due to the friction film flowers and crushed most of the clean up is not in place especially dense line spacing of 2.7 lines in the exposure of board sports physical work such long hours difficult to imagine film post production too long and the protective film using the old light transmission is also a problem affecting

exposure where exposure energy instability exposure machine wipe the glass with dirty spots and spend a rare but easy to control this problem

and then to develop and etch lithography and etching speed and temperature control are likely to produce poor child had residual copper is almost no turning back a grade if they are Agua etching in command of the board washed only plastic film may of course have not seen this quack but most of residual copper left here

line problem Well, of course searching for answers from the line where the formation of a

gap open stubs biggest copper still short by far the most likely of which took place in the inner clean room

Speaking from the coating machine coating round the control of ink will be scratched coating caused by poor coating bad Needless to say the line is not a prerequisite for the formation of the problem that is certainly a lot of good drops

then divided into two parts where exposure exposure exposure one second film

first film with the problem that most frequently is this Lifei Lin is expected to produce the most important number of retired high-volume wash with the scrap is a problem here, and out from the film to production problems on a lot of exposure machine there are line problems mainly due to the friction film flowers and crushed most of the clean up is not in place especially dense line spacing of 2.7 lines in the exposure of board sports physical work such long hours difficult to imagine film post production too long and the protective film using the old light transmission is also a problem affecting

exposure where exposure energy instability exposure machine wipe the glass with dirty spots and spend a rare but easy to control this problem

and then to develop and etch lithography and etching speed and temperature control are likely to produce poor child had residual copper is almost no turning back a grade if they are Agua etching in command of the board washed only plastic film may of course have not seen this quack but most of residual copper left here

added: 1, the whole line did not face the entire plate surface clean, leaving oil or resin, and the like, not the cause behind the etching, the formation of residual payments.

2, the phenomenon of dry and liquid reaction will form a difficult to dissolve the coagulum, and will stick to the plate, etching time, the following can not be etched out of copper, the formation of residual gold

3, the most interesting is that, before plating the entire surface is not clean, leaving the residual gum resin or the like, caught in copper after electroplating the middle, in the etching line, simply is not saved, only to see AOI examination, which her brother’s highly skilled repair plate, and brother saw the board width spacing is 100, which led to my eyes almost blind.

4, the most sand ratio is, the phenomenon of tear resin protective film before etching time, clean, no tear, leaving one, can imagine the etching line staff to see what this phenomenon is the expression ha ha ha ha. . . Only redo

inner flaws — common defects of wet membrane level example:

(open, gap, pinhole) cause the reasons:

1. Pre-cleaning of the treatment effect and the extent of the clean oven;

2. coating quality and clean degree oven, bake curve is correct

3. Exposure levels inside a clean, light energy

4. Exposure Room cleanliness

If the ink properly, as long as the 5S buttoned, defects can easily fall down.

scratch:

1. officers, board process caused

2. machine because

residual copper:

1. baking curve

2. Exposure energy

3. enhancement of the etching

short circuit:

short-circuit can be divided into a bad light machine vacuum vacuum caused by short circuit (corner or edge of the feed volume dirt particles can cause such a phenomenon)

The other is the imaging and etching line problem.

fill line to see customers and the use of the board:

Automotive board and important board equipment can not fill, simple electronic products

inner short, to many:

1, clean room dust levels, to strengthen the Clean

2, film location and spam

3, inner layer etching is not a net

4, laminated riveting garbage and residues of copper rivets out on the plate

5, laminated with the environment is not good, how dust

6, man-made improper operation

you brother had: to ask whether it is analyzed the inner layer are due to short circuit which caused the bad processes? Thank you! I have not been able to play sections look at what it caused.

I do the inner, inner potential for something to publish comments:

1, plate itself debris. Including internal and copper plate surface.

plate inside the debris within the most direct impact is short-or high-pressure failure.

can lead to the inner surface of copper etching of the residual copper.

2, the inner layer of debris before the treatment.

is the equivalent of such issues in the copper plate itself, the surface debris. Note that when stacked in the stacked plate thickness, so that debris is compacted at the plate surface,PE film, difficult to handle.

3, the depth of oxidation pre-treatment before.

foil such issues can lead to rejection membrane.

4, the inner washer to return back to a net wash.

5, do not know if you are not used wet foil. We use a vendor’s (inconvenience that) foil the dry when wet,Protective film, there have been such a problem: After the foil, if the board has left stains in the imaging, the plate surface by imaging the region have residual thin layer of dry, hard to find the naked eye. There is a residual copper after etching. This issue has been resolved.

6, foil over edges, resulting in a large number of film pieces.

7, foil parameter is used inappropriately, leading to imaging difficulties.

8, overexposure

9, film flower rub

10, exposure, exposure is not complete, this problem will lead to develop when the jelly.

first list of 10, do report the first!

inner flaws — common defects of wet membrane level example:

(open, gap, pinhole) cause the reasons:

1. Pre-cleaning of the treatment effect and the extent of the clean oven;

2. coating quality and clean degree oven, bake curve is correct

3. Exposure levels inside a clean, light energy

4. Exposure Room cleanliness

If the ink properly, as long as the 5S buttoned, defects can easily fall down.

scratch:

1. officers, board process caused

2. machine because

residual copper:

1. baking curve

2. Exposure energy

3. lithography and etching

short circuit:

short-circuit can be divided into a bad light machine vacuum vacuum caused by short circuit (corner or edge of the feed volume dirt particles can cause such a phenomenon)

The other is the imaging and etching line problem.

fill line to see customers and the use of the board:

Automotive board and important board equipment can not fill, simple repair of electronic products

you are not using the wet film are, ah, no one mentioned the depression plate. For some dry, very minor depression are covered conceal. And a large part of the depression caused by the defects open gap is similar with the other!

experiments I have done some providers that specifically depression acceptable to do in the 3,4 mil online, those defects could not distinguish with some other flaws, in fact, all depression. Transfer a map with you to see.

map is not done first before the (very slight depression), the second after the map is etched

Figure 1 is a plate in a watermark, dry sparkling bad the exposure;

Figure 2 laminated excessive pressure;

Figure 3 is a pre-processing board in too rough, jagged irregular plating a must.

You can verify this.

If there is affixed film protective film, protective film that is scratched, the barrier between the film and plate exposure leading to bad. Do not believe you can make a try

protective film for the film posted blistering problem, you can make the film by a new protective film in the paste before the air exposure on the exposure of a few years after the protective film paste line in Figure 1 has been deformed and ring under dry watermark should be dried before processing result;
Figure 2 Short circuit Department

different dry colors, apparently not exposed here, as is the anti-stick when dry lithography imaging here is not caused by the net;

Figure 3 has obvious scratches, the shape from scratch Department is not a film to see the problem, should be a foil laminated after the exposure caused by the weight before.

personal opinions only.

ways to improve this problem.

crush will also appear after developing adverse conditions Figure 3

two problems are not the bulk of it? if that test or develop the film room during the operation when scratched.

problem, if not volume, it can check the cleanliness of non-forest.

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