Cutting process
Cutting is the entire FPC source material production of the first station, the quality of its larger impact on the latter, but also a control point of the cost of the cutting machine due to the degree of high mechanical performance and maintenance of machinery is very important. And the precision of the cutting machine equipment can basically reach the precision requirements of the cutter, so the operator's operating technology and proficiency and responsibility to improve the focus.
1. Knowledge of raw material codes
E.g.: B 08 N N N 0 0 R 1 B 250
B Copper Foil
08: Manufacturer's code
1N Layer, N, Copper Sheet S, Single Panel, D, Duplex
2N Insulation Category N. No Insulation Category K. kapthon P. polyster
2N Insulation Category K. Polyster
3. polyster
10 Insulation thickness 0,no 1:1mil 2:2mil 20 Insulation with or without adhesive between insulating layer and copper sheet
0;no 1;yes
R,Copper skin category A:Aluminum foil H:Highly ductile Electrolytic Copper
R:Calendered Copper E:Electrolytic Copper
1,Copper skin thickness
B. Copper skin treatment R:Brownish G:Normal 250,Width code Cover lay coding principle.
2. Process Quality Control
Based on the first piece
A. The operator should wear gloves and finger cots to prevent the surface of the copper foil from oxidizing due to sweat stains on the hands.
B. The correct way to rack the material to prevent folding.
C. Don't cut out of shape, and don't damage the punching position hole and test hole when cutting by hand. If there is no special instruction, the cutting tolerance is ±1mm in the sheet cutting
D. Cutting within 0.3mm.
E. Cutting size should not have a large error, and pay attention to its verticality, that is, cut for the sheet when the four sides should be vertical (<2 °).
G. Material quality, the surface of the material can not have wrinkles, stains, heavy oxidation phenomenon, the cut material can not have burrs, overflowing glue and so on.
3. Mechanical maintenance
Strictly in accordance with the & lt; automatic cutting machine maintenance inspection record table & gt; the implementation.
CNC drilling:
CNC is the first station of the whole FPC process, and its quality has a great influence on the subsequent program.
Basic CNC process: grouping boards → PIN → drilling → back PIN.
1. Grouping boards
Selection of cover boards → grouping boards → adhesive tape → hit the arrow (mark)
Basic grouping boards requirements:
Single panel 15 single copper 10 or 15 double 10 single copper 10 or 15
Yellow Coverlay 10 or 15 single copper
Single panel 10 or 15 double copper 10 or 15
The CNC is the first station of the entire FPC process, its quality has a great impact on the subsequent program. Yellow Coverlay 10 or 15 sheets White Coverlay 25 sheets Auxiliary plate 3-6 sheets according to the situation
Main function of the coverlay:
A:Reduce the hole feeding burr
B:Prevent the drill and pressure foot from pressing on the material surface
C:Make the center of the tip of the drill easy to locate to avoid skewing of the drilling position
D:Take away the drill tip to avoid the drilling of the hole. p>D:Take away the heat generated by the friction between the drill bit and the hole wall. Reduce the twisting breakage of the drill bit
2. Drill control methods
a. Control of the number of times of use b. Identification of new drill bits c. Inspection of new drill bits
3. Quality control points
a. Correctness; based on the drill sheet and drilling data to confirm the correctness of the product hole position and the number of holes, and check the broken needle to monitor the holes to see if the holes are completely through
d. Appearance quality
3. p>d. Appearance quality; there should be no copper warping, burrs and other bad phenomena
4. Process control
a. Product confirmation
b. Process confirmation
c. Combination confirmation
d. Dimensional confirmation
e. Positional confirmation
f. Programmatic confirmation
g. Tooling confirmation
g.
h. Coordinate confirmation
i. Orientation confirmation.
5. Common causes of defects
Needle breakage
a. Improper operation of the drilling machine b. Problems with the drill bit c. Feed too fast
Burrs
a. Incorrect cover and pad b. Incorrect drilling conditions c. Static adsorption, etc.
7. Good quality of the drilling
a. Operator's technical ability, sense of responsibility, and proficiency
b.
b. Drill pins; material, shape, number of drills, drill tip
c. Platens; pads; material, thickness, thermal conductivity
d. Drilling machine; vibration, positional accuracy, clamping force, auxiliary performance
e. Drilling parameters; batch/single processing method, number of revolutions, feed/release speeds, etc.
e. Drilling parameters; batch/single processing method, number of revolutions, feed/release speeds, etc.
f. Drill parameters; batch/single processing method, number of revolutions, feed/release speeds, etc.
e. Drilling parameters; batch/single processing method, number of revolutions, batch/release speeds, etc.
f. Processing environment; external forces
h. Motion, noise, temperature, humidity
P.T.H station
1. Principle and function of PTH
PTH is the process of plating copper ions on the surface of the activated hole walls and copper foils through the autocatalytic redox reaction of the plating solution (with palladium and copper atoms acting as catalysts), without applying any external current. And copper foil surface process, also known as chemical copper plating or autocatalytic copper plating, chemical reaction equation:
2.PHT process and the role of each step
The whole hole → washing → micro-etching → washing → washing → pickling → washing → washing → washing → pre-dip → activation → washing → washing → speed → washing → washing → washing → chemical copper → washing.
a. Hole preparation; clean the surface of the plate, polarize the negative charge of the hole wall to positive charge, which is conducive to the adhesion of the negatively charged palladium colloid.
b. Micro-etching; cleaning the plate; roughening the surface of the copper foil to increase the adhesion of the coating.
c. Acid washing; cleaning of the plate; removal of oxidized layers, impurities.
d. Pre-leach; to prevent contamination of the activation bath.
e. Activation; to make the palladium colloid adhere to the pore wall.
f. Rapidization; reduces Pd ions to Pd atoms so that the chemical copper can be tin-plated.
g. Chemical Copper: Deposits copper on the hole wall and the surface of copper foil by chemical reaction.
3. PTH common bad conditions of treatment
1. hole without copper
a: activation of palladium adsorption deposition is not good.
b: Speed chemical tank: speed chemical agent solubility is not right.
c: chemical copper: the temperature is too low, so that the reaction can not be carried out reaction speed is too slow; tank liquid composition is not right.
2. hole wall particles, rough
a: chemical tank particles, uneven deposition of copper powder, must be installed filter device.
b: The plate itself has burrs on the hole wall.
3. Blackening of the plate
a: chemical bath composition is not right (NaOH concentration is too high)
b: building bath when building bath agent is not enough
Copper plating:
Copper plating that is to improve the uniformity of plating in the holes, to ensure that the entire layout (holes and holes near the mouth of the entire plating) plating thickness to achieve a certain level of requirements.
Process control: product confirmation, process confirmation, liquid confirmation, confirmation of machine parameters.
Quality control:
1, penetration: the first slot to draw 2, with a 20 times magnifying glass to check the hole wall whether the copper plating is completely attached to the penetration.
2, surface quality: the surface of the copper foil must not have burnt, peeling, granular, pinhole and spotting bad phenomena.
3, adhesion: in any one of the board edge of about 2.54 * 2.54cm2 area to slice from the axis of the horizontal axis of each of the 10 cuts, and then 3M tape paste 3 minutes after the vertical upward pick up there is no shedding phenomenon.
Chemical copper every week should be inverted groove, role: copper deposits in the bottom of the groove, the bottom of the groove more and more copper, the more the consumption of potion, thus making the cost higher.
Slice experiment:
Procedure:
1, prepared slices of acrylic powder and potion, Vaseline, jigs, utensils.
2, according to the requirements of the sample to make a test piece.
3, first in the inner surface of the vessel evenly coated with a layer of lubricating effect of petroleum jelly.
4, the specimen is clamped with a jig and placed in the vessel.
5, the acrylic powder and acrylic solution in the ratio of 10:8 mixing and slowly poured into the vessel.
6, take it out directly after it solidifies and molds.
7, the slices were placed on a metallographic specimen pre-grinder and ground and polished until they met the requirements and then observed with a metallographic microscope and recorded their values.
Paste film:
1, dry film pasted on the plate, by dew light after developing, so that the line is basically molding, in this process the dry film mainly plays the function of the image transfer, but also in the process of etching play a role in protecting the line.
2, dry film is mainly composed of: PE, photoresist, PET. Among them, PE and PET only play a role in protection and isolation. Photoresist includes: linker, initiator, monomer, adhesion promoter, color.
Operation Requirements:
1、Keep the dry film and board surface clean.
2, flatness, no bubbles and wrinkles.
3 ﹑ adhesion to meet the requirements of the high degree of adhesion.
Operation quality control points:
1, in order to prevent wire breakage when applying the film, we must use dust-free paper to remove impurities on the surface of copper foil first.
2, should be set according to the temperature of the heating roller, pressure, speed and other parameters.
3, to ensure that the direction of the copper foil hole in the same orientation.
4, to prevent oxidation, do not directly touch the surface of the copper foil, if the phenomenon of oxidation to use fiber brush to brush off the oxide layer.
5, there should be no scars on the heating roller to prevent wrinkles and poor adhesion.
6, leave 15min-3 days after the film, and then go to the dew light, too short a time will make the dry film by UV light irradiation, the organic polymerization reaction that occurs is not complete, too long it is not easy to be hydrolyzed, residue occurs leading to poor plating.
7, often use dust-free paper to wipe away impurities on the heating roller and overflow glue.
8, to ensure good adhesion of the film.
Quality Confirmation:
1, adhesion: after the film to Hitachi test negatives for testing, after exposure and development of the line can not be bent deformation or broken, etc. (with a magnifying glass to detect)
2, flatness: must be flat, no wrinkles, bubbles.
3, cleanliness: each sheet shall not have more than 5 points of impurities.
Exposure:
1. Principle: make the line through the action of dry film transferred to the board.
2. Points of operation:
Working to keep the negative and the board clean; the negative and the board should be aligned correctly; there should be no air bubbles, impurities; put the film should be careful to expose the hole.
Double-sided board operation should be padded with black paper to prevent exposure.
Quality Confirmation:
1. Accuracy:
a. Positioning hole offset +0.1/-0.1 or less
b. Soldering point of the tin ring can not be less than 0.1mm (can not be holes in the principle of broken)
c. Through the hole of the tin ring can not be less than 0.1mm (can not be holes in the principle of broken)
2:
No negative factors of fixed broken lines, pinholes or short-circuit phenomenon
Negative specifications, exposure energy of the exposure machine, the negative and the tightness of the dry film will affect the line of precision.
*The purpose of vacuuming is to increase the tightness of the film contact with the dry film and to reduce astigmatism.
*Exposure energy level also has an impact on the quality:
1, low energy, exposure is not enough, after the development of resist is too soft, gray color, etching resist destruction or floating, resulting in circuit breakage of the line.
2. High energy, it will cause overexposure, then the line will be shrunken or the exposure area is easy to wash out.
Development:
Principle:
Development is to have been exposed to light with a dry film of the plate, through the development of liquid (7.9g / L of sodium carbonate solution) treatment, will not be UV light irradiation of the dry film washed away and retained by the UV light irradiation of polymerization of the dry film so that the line of the basic shape.
Factors affecting the quality of imaging operations:
1 ﹑ developer composition.
2, developing temperature.
3, developing pressure.
4, the uniformity of the distribution of the developer.
5, machine rotation speed.
Process parameters control: solubility, development temperature, development speed, spray pressure.
Development work quality control points:
1 ﹑ No water droplets should not be out of the mouth trigger, should be blown clean.
2, there can not be untorn dry film protective film.
3, the image should be complete, the line can not be jagged, bending, thinning and other conditions.
4, after the image of the bare copper surface with a knife to scrape the dry film must not fall off, otherwise it will affect the quality of the moment job.
5 ﹑ dry film line width and negative line width control within + / - 0.05mm error.
6 ﹑ line complex side down to avoid film residue, to reduce the pool effect caused by uneven development.
7 ﹑ According to the solubility of sodium carbonate, dry film load and the use of time to update the film solution to ensure the best development effect.
8 ﹑ control the developer, the level of water.
9, blow drying wind should be kept inward 5-6 degrees.
10 ﹑ should be regularly cleaned tank and nozzle, nozzle in the scale, to prevent impurities contaminated plate and cause uneven distribution of developer.
11 ﹑ to prevent the operation of the cardboard, cardboard should be stopped when the rotation device, should immediately stop the release of the plate, and take out the plate sent to the middle of the development platform, such as not fully developed, due to the second development.
12 ﹑ development after blowing dry the board should be separated from the absorbent paper to prevent dry film adhesion and affect the quality of the moment.
Confirmation of quality:
Completeness: after the development of bare copper surface with a razor blade to gently scrape the dry film must not be left.
Appropriateness: The edge of the line should not be jagged or the line should not be thinned or warped, and the line width of the dry film and the line width of the negative should be within +0.05/-0.05m after the image is developed.
Surface quality: Blow-drying is required, and there should be no water droplets left.
Etching stripping:
Principle: etching is at a certain temperature conditions (45 +5) etching solution through the nozzle uniformly sprayed to the surface of the copper foil, and no etching resist protection of copper redox reaction, and the unwanted copper reaction off, exposing the substrate and then stripping the film treatment to make the line shape.
The main components of etching solution: copper chloride, hydrogen peroxide, hydrochloric acid, soft water (solubility has strict requirements)
Quality requirements and control points:
1 ﹑ can not have residual copper, especially double-sided board should be noted.
2, there can be no residual glue, otherwise it will cause copper or plating adhesion bad.
3, etching speed should be appropriate, do not allow excessive etching caused by line thinning, etching line width and total pitch should be the focus of this site control.
4 ﹑ line soldering points on the dry film shall not be flushed separation or fracture.
5 ﹑ Etching stripped film after the plate does not allow oil, impurities, copper skin warping and other poor quality.
6 ﹑ put the plate should pay attention to avoid cardboard, to prevent oxidation.
7 ﹑ should ensure that the etching solution distribution of uniformity, to avoid the front and back or the same side of the different parts of the etching is not uniform.
Process control parameters:
Temperature of etching solution: 45+/-5℃ Solubility of hydrogen peroxide: 1.95~2.05mol/L
Temperature of film-peeling solution: 55+/-5℃ Temperature of etching machine ≦55℃
Drying temperature: 75+/-5℃ Distance between front and rear plates: 5~10cm
Special weight of copper chloride solution: 1.5~10cm
Special weight of copper chloride solution: 1.5~10cm
Special weight of copper chloride solution: 1.5~1cm Specific gravity of copper chloride solution: 1.2~1.3g/cm3 Angle of plate release, guide plate, upper and lower nozzle switching status
Hydrochloric acid solubility: 1.9~2.05mol/L
Quality Confirmation:
Line width: Etching standard line is .2mm & 0.25mm, the etching must be within +/-0.02mm.
Surface quality: no wrinkles or scratches.
Copper residue is not allowed to be detected by light transmission.
The line must not be deformed
No oxidized water droplets
Glossy tin-lead
One of the common defects in the process and its causes:
1. Poor bonding (poor adhesion). Pre-treatment is poor; current is too high; there are copper ions and other contamination.
2. The plating layer is not bright enough. Not enough additives; tin-lead ratio is not appropriate.
3. Gas precipitation is serious. Too much free acid; divalent tin-lead concentration is too low.
4. Turbid plating. Too much tin-lead colloid, the formation of precipitation.
5. Plated layer is dark. Too much anode mud; copper foil contamination.
6. Tin plating thickness is large. Plating time is large.
7. Tin plating thickness is small. Plating time is not enough.
8. Exposed copper. There are overflowing glue.
2 ﹑ quality control ﹕
1 ﹑ first inspection must be 3M600 or 3M810 tape test pull, to verify its adhesion
2 ﹑ should check whether the plated point is completely plated, there can not be unplated and exposed copper
3 ﹑ there must be a glossy, there can not be blackened, rough or burned
4 ﹑ x-ray thickness meter to measure the thickness of plating
5 ﹑ the thickness of tin plating, the thickness of the plating, the thickness of the plating. Plating thickness
* In the current density of 2ASD, 1 minute about 1um plating.
Three ﹑ plating conditions set to determine the factors:
1 ﹑ current density selection
2 ﹑ the size of the plated area
3 ﹑ the thickness of plating requirements
4 ﹑ plating time control
Four ﹑ appearance inspection
1 ﹑ plated area size
3 ﹑ plated thickness requirements
4 ﹑ appearance inspection
4 ﹑ plating time control
4 ﹑ appearance inspection
1 ﹑ plating thickness measurement tool for X-Ray measuring instrument
2 ﹑ plated point completely plated, can not be missed on the abnormal phenomenon
3 ﹑ plating can not be blackened or rough, burnt
4 ﹑ plating can not be pockmarked, exposed copper, color, hole broken, uneven phenomenon
5 ﹑ 3M600 or 3M810 tape test pull, can not fall off the tape. Tape test pull, do not have the phenomenon of shedding
Grinding:
Grinding is the FPC process may be used many times in an auxiliary process, as other processes of pretreatment or post-treatment process, generally the first board for acid pickling, micro-etching or oxidation treatment, and then the use of nylon wheels on the surface of the board for the surface of the board to remove the board's surface impurities, blackened layer, residual adhesive, and so on.
Grinding procedure:
Input - blackened layer - washing - grinding brush - pressure washing - cutting water to squeeze dry - blow dry - drying - discharge
Grinding type:
1 ﹑ to be affixed to the film: double-sided board to oxidation, stretching (hole offset) single panel: de-oxidized
2 ﹑ to be false affixed to the Coverlay: sanding, red spot (peeling film) to remove. Coverlay: Remove red spot (NaOH residue after peeling off the film), de-oxidize
3 ﹑ to be false sticker coverlay: sanding, cleaning
4 ﹑ to be plated: sanding, cleaning, to increase the adhesion
5 ﹑ after plating: drying, to improve the gloss
Surface quality:
1. All the places needing to be abraded are uniformly abraded with traces of brushes.
2. The surface should be dried completely without oxidization or water droplets.
3. There should not be any wrinkles and crumpling caused by the water cutting roller.
4. There should be no copper skin warping due to abrasion and brushing, or copper powder accumulating on the edge of the coverlay and warping.
Common defects and prevention:
1, the surface of the water droplet traces, this time you should check whether the sponge roller is too wet, should be cleaned regularly, squeeze the water.
2, oxidized water completely removed, check whether the pressure of the brush wheel is sufficient, whether the transfer speed is too fast.
3, blackened layer removal is not clean.
4, brush grinding is not uniform, you can use a single sheet of copper foil to check whether the brush grinding is uniform.
5, due to the cardboard caused by wrinkles or broken lines.
Spotted first post --- a brief history of the development of the PCB process
1.1 general terminology
Printed circuits - in the insulating substrate, according to the predetermined design of the formation of printed components or printed lines and the combination of the two conductive graphics.
Printed circuit - a conductive pattern formed on an insulating substrate and used as an electrical connection between components.
Printed board - The finished printed circuit or printed circuit board is commonly referred to as a printed board.
Multilayer printed circuit board - a printed circuit board consisting of more than two layers of conductive graphics bonded alternately with insulating material and interconnected with conductive graphics between the layers.
Flush printed circuit boards - printed circuit boards in which the outer surface of the conductive pattern and the outer surface of the insulating substrate are in the same plane.
1.2 Printed boards in electronic equipment function
1, to provide integrated circuits and other various electronic components fixed, assembled mechanical support.
2, the realization of integrated circuits and other various electronic components between the electrical connection or electrical insulation. Provide the required electrical characteristics, such as impedance.
3.Provide solder resist graphics for automatic soldering. Provide identification characters and graphics for component installation, inspection, and maintenance.
1.3 Brief history of development
1. The basic concept of printed circuits was mentioned in patents in the early 20th century.
2. The first technical symposium on printed circuits was initiated by the AAA and the U.S. Bureau of Standards in 1947.
3, the early 1950s, due to the copper foil laminate copper foil manufacturing technology can be solved and laminate adhesive strength and its resistance to soldering problem solved, its stability can be *, the realization of industrialized mass production of printed circuit boards. Copper foil etching method has become the mainstream of printed circuit board manufacturing technology.
4, 60's, plated holes double-sided printed circuit board to achieve mass production.
5, 70 years, the rapid development of multilayer printed circuit boards.
6, 80's, surface mounted board (SMB) gradually replace the cartridge printed board, and become the mainstream.
7, since the 1990s, surface mounting from the four-sided flat package (QFP) to the ball grid array package (BGA) development. At the same time, chip-scale packaging (CSP) printed circuit boards and organic laminate materials as a substrate for multi-chip module packaging technology (MCM-L) with the rapid development of printed circuit boards.
8, in 1990, Japan's IBM developed a surface laminar circuit technology (surface laminar circuit) (SLC)
9, the ability to produce BUM (laminated multilayer boards) has now become an important measure of the technology of a printed circuit board factory.
10, the United States in 1994, the establishment of the Interconnection Technology Research Institute (ITRI), put forward the concept of high-density interconnection HDI board its aperture ≤ φ0.15mm, aperture ring diameter of ≤ φ0.25mm, line width and spacing of ≤ 0.075mm.
1.4 Typical process of printed circuit boards
1.4-1 single-sided printed circuit boards. Typical process:
Single-sided copper-clad board → material → punching (drilling) reference holes → grinding board → air-drying → screen-printed resist graphics → curing → etching → remove (descaling) film → drying → inspection → grinding board → screen-printed solder resist graphics → curing → screen-printed marking characters → curing → drilling punching holes to locate the die → preheating → monumental boards → testing → cleaning → flux coating → drying → inspection → packaging → warehouse
1. 4-2 Double-sided printed circuit board canonical shape process:
① graphic plating - etching process:
Double-sided copper-clad board → material → CNC drilling → copper sinking → grinding board → dry film or coating wet film → exposure development → inspection and repair of the board → graphic plating → de-film → etching → inspection and repair of the board → screen printing solder resist graphics → curing → screen printing characters → curing → molding → cleaning → inspection and packaging → storage
1. Inspection → packaging → warehouse
② hot air leveling process:
Unloading → drilling → copper sinking → graphics transfer → electric tin-lead → film removal → etching → retiring tin-lead → inspection and repair of the board → screen printing solder resist → hot air leveling → screen printing characters → molding → cleaning → inspection → packaging → warehouse
1.4-3 typical process of multilayer printed circuit boards:
Opening → milling board → paste Dry film or coated wet film → inner layer line → exposure development → etching → inspection and repair of the board → blackening → stacking → lamination → inspection → drilling → expansion → de-gumming slag → neutralization → copper sinking → graphic transfer → plating → inspection and repair of the board → screen printing solder blocking → screen printing characters → molding → cleaning → finished product testing → inspection → packaging → warehouse
1.4-4BUM Typical Process:
① core board → plugging holes → Coated with light-sensitive epoxy resin → exposure, development of blind holes → chemical copper plating (copper sinking) → conductor graphics to form the first layer → repeat the coating of light-sensitive epoxy resin to form the second layer → coated with soldermask → connecting disk plating → finished board
① chip → plugging holes → both sides of the resin attached to the copper foil → blind holes drilled by laser → drilling holes drilled by mechanical drilling machine through the holes → immersed copper → outer layer of the conductor graphics to produce soldermask → connecting disk plating → finished products
1.4-4BUM typical process disk plating → finished product
1.5 Printed board production technology development trends
1.5-1CAD / CAM system
① have the function of dealing with the photographic negative
② the system has a design rule check (DRC) or manufacturing rule check (MRC)
③ have the plating of the copper area calculations
④ there is a deletion of the pads Character function
⑤ Delete the useless pads for the inner layer of the multilayer board
⑥ Increase the row of adhesive strips for the multilayer board pressing, etc.
1.5-2 high-precision photographic plate production technology
① Photolithography machine to the direction of high-precision and high-speed development.
Israel ORBOTECH company's light painting system accuracy of up to 0.003mm
② new plate making methods - the use of metal film film laser direct imaging, such as Belgium BARCO company developed Elise laser direct imager, the use of Agra company direct imaging Film, the minimum line diameter of up to 0.05mm, its accuracy <2um, repeatability <3.2um.
1.5-3 blind holes, buried holes in the manufacturing technology
① Blind holes are connected to the outer layer of the multilayer board and one or more inner layer of copper-plated holes.
② Buried holes are copper-plated holes that connect two or more inner layers inside the multilayer board.
③ Buried holes and blind holes are mostly small holes of 0.05-0.15mm.
1.5-4 High-precision, high-precision, fine wire imaging technology
① Dry film to the thin, Mylar-free, high-speed sensitization and special-purpose direction.
② Wet film technology
③ ED resist
The use of electrodeposition (ED) resist is the current production of fine wire advanced PCB process. The process is:
Surface treatment → ED electrodeposition (10-20um thick) → washing → drying → coating protective layer (PVA1-3um thick) → drying → cooling → photographic imaging.
④ ED resist materials sold by DuPont of the United States, Kansai Coatings of Japan.
⑤ laser direct imaging technology: CAD / CAM system with a direct laser imaging machine, direct scanning of specialized laser-type photosensitive dry film and imaging. General dry film can make 0.10mm fine wire; wet film for 0.075mm; Pu type and no Mylar and ED resist, laser imaging for 0.05mm.
The use of pumice powder brushing machine or chemical cleaning equipment instead of nylon abrasive brushing machine and parallel light exposure machine can improve the accuracy of the fine wire process.
1.5-5 microscopic holes deep hole plating technology
①The plate thickness / hole diameter ratio greater than 5 holes are called deep holes.
②In deep hole plating, because the hole diameter is small and deep. Plating power line distribution is not uniform, the plating solution in the hole is not easy to flow exchange. Easy to occur in the hole wall bubbles and other reasons, hole wall plating uniformity is difficult to achieve.
③Direct plating technology
A: carbon film method, the American Electrochemical Company's shadowTM process; MacDemid's black hole technology.
B: Palladium film method, crimson process of American shipley; Neopect process of Atotech.
C polymer conductive membrane method. DMS technology from Blasberg, Germany.
1.5-6 BUM technology
1.5-7 hole plugging technology (hole plugging technology)
1.5-8 clean technology
1.5-8 ① photographic plate, film exposure, screen printing, multilayer board stacking requirements (constant temperature of 20 ± 2 ℃ humidity of 55 ± 10% Rh)
② the production of 0.13 mm fine Wire cleanliness requirements 10000 level, process water resistance greater than 1MΩ deionized water.
1.5-9 Cleaner Production
① Implementation of ISO14000
② Requirements A saving of raw materials and energy, B cancel the toxic raw materials, C to reduce emissions and toxicity of waste.
1: Engineering, light drawing
Collection of documents → document processing → based on customer requirements combined with the company's equipment, technical capabilities to determine the production program → the preparation of engineering instructions, production production orders → processing, light drawing film → screen, jigs, molds ready
2: opening, drilling
a . Hole processing methods: beer hole, manual drilling, CNC drilling, milling, laser drilling
b. The quality of CNC drilling process
① good or bad drilling machine
② the quality of the drilling nozzle, the type of drilling, geometric open shape, material, precision, turning and grinding quality.
③ Process parameters: cutting speed, feed speed, rotational speed, life.
④ Cover plate quality
⑤ Plate quality: material, thickness, copper thickness, resin content, flatness.
⑥ Processing environment: experience, temperature and humidity, external vibration, lighting, management.
3: Hole Metallization
a. Hole Metallization Methods: Hollow Rivet Connection, PTH (Sinking Copper), Direct Plating (Palladium Series, Conductive Polymer Series, Carbon Black)
b. PTH (Sinking Copper) Process:
Drill Plate→Deburring→Cleaning and Adjustment Process→Micro Etching (Roughening)→Pre-immersion→Activation→ Sinking Thick Copper (1.5- 2.0um) → antioxidant → sinking book copper (0.3-0.5um) → immersion dilute acid → full-board copper
① to remove drilling stains: H2SO4 (86% or more), KMnO4 (potassium permanganate) dissolved → potassium permanganate → neutralization
② micro-etching: removal of copper surface oxidation, etching off the copper layer of 2-3um, so that the surface of the copper roughness.
③Pre-immersion: Prevent water from being brought into the activation solution and prevent the concentration and PH value of the activation solution from changing.
④ Activation: adsorb a layer of metal particles with catalytic ability on the insulating substrate, so that the surface of the activated substrate has the ability to catalyze the reduction of metal, thus making the reaction of chemical copper plating proceed smoothly.
⑤ Acceleration: 5% NaOH solution to improve the activation performance of colloidal palladium.
⑤ Copper precipitation: autocatalytic reduction reaction, Cu2+ gets electrons to be reduced to metallic copper, the reductant releases electrons and itself is oxidized.
4: Image transfer:
a. Image transfer methods: screen printing resist graphics, negative contact exposure technology, laser direct imaging
b. Process: coating wet film → pre-bake → cooling → paste dry film static → static cooling plate → exposure → development → check
c. Factors affecting the quality of the image transfer
① ambient temperature and humidity
② photographic substrates
c.
② Quality of photographic negative
③ Equipment
④ Process Technology
5: Plating
1. Tin-lead plating
Process: Acid Copper Plating→
2. Nickel gold plating
3. Immersion nickel gold, tin, silver, palladium
Hot air leveling (63sn.37pb)
OSPC (Organic Flux Shield) Technology
6: QC Inspection (MI2, MI3)
Inspect PCB appearance and function by visual or tester to see if it meets the requirement
7: Silkscreen
a.Process:
Board Cleaning→Printing Soldermask→Prebaking (75±5℃)→Exposure, Developing→After Baking (150 C)
Curing oil (150 ℃, 60 minutes)
b. The purpose of the pre-bake: is to evaporate the solvent contained in the ink (about 25%), so that the film becomes non-stick substrate state, in order to facilitate the exposure operation. Pre-bake is not enough, the exposure will stick to the substrate, indentation, contamination of the substrate, the surface loses its luster and develop the oil and other issues; pre-bake temperature is too high, too long, there will be development of unclean, causing bad tin and other issues.
c. The purpose of post-baking: so that the solder resist ink thoroughly cured, the formation of a solid mesh structure, to achieve its electrical and physical and chemical properties.
d. The role of soldermask: to prevent wire scratching, moisture resistance, heat resistance, insulation, aesthetics and other functions.
8: Molding
Method: shearing, punching, gong, V-cut, laser cutting.
9: Packaging
a. Process:
Dust blowing→board cleaning centrifuge→dry board→inspection→FQC→packaging→OQA→in storage→board washing machine
b. Functions of Packaging:
Moisture-proof and humidity-proof, beautiful and damage-resistant, easy to be transported and easy to be counted.