7. The design of PCB（multiple layer board)-- Process of multilayer board

Multiple Layer Board
 Juvtmall ( a company supply PCB Prototyping, PCBA service and sell kinds of components, modules and so on) 

PCB Multilayer Board means multilayer board used in electrical product, it involves wild area, such as home appliance, computer accessories, communication, toy, instrument, LED and so on.
PCB(printed circuit board) Multilayer Board is consist of track on several layer of insulation substrate and pad, it has two function: conduct every layer’s circuit, insult mutual layer. As the develop of SMT, the launch of new SMD (such as QFP, QFN, CSP, BGA), electrical product become more intelligent and smaller. Since HDI is created, the develop these process technology lead the design of PCB to multiple layer, and high density.  



1. Process of multilayer board
  1. PCB which has draw the track:
Put on the board, acidity deoiling, scanning rinsing, second reflux rinsing, micro etch, scanning rinsing, second reflux rinsing, presoak copper plating, copper plating, scanning rinsing, presoak tin plating,  tin plating, second reflux rinsing, off the board.
2. Detail of multilayer PCB’s process
2.1 presoak of tin plating
2.1.1  consist of tin plating and operating conditions of tin presoak
2.1.2  method of tin plating   
  Add half vat of distilled water, then add 15L vitriol whose mass fraction is 98%, add 1.5 L sulfotech part A after the water and vitriol has being stir in to cool, stir them, then add distilled water to make all of them reach 300L, stir well, then it can be use.
2.1.3  Maintenance and controlling of presoak tin plating
  Deal 100㎡ board need 1L vitriol and 100mL Sulfotech Part A, the bath will be replaced after dealing 1500㎡board.
2.2  Tin Plating
2.2.1  Combination and operating conditions of tin plating electrolyte 
2.2.2  Method of open tin pot
Add half vat of distilled water, add vitriol whose mass fraction is 98%, after them cool down, add 40 kg Tin Salt 235, cool them to 25 ℃, then add 76L Sulfotech Part A, 15.2 L Solfotech Part B, 30.4L STH Additive Sulfolyt, finally, add distilled water to liquid level.
2.2.3  Maintenance and controlling of presoak tin plating
Deal per 100㎡ board, need 11L vitriol, 600g Tin Salt 235, 600mL Sulfotech Part A, 800mL Sulfotech Part B, 750mL STH Additive Sulfolyt. Auto add system add 56mL Sulfotech Part A per 200AH.
Solution must be test by Hull cell test, observe and adjust Sulfotech Part A, Sulfotech Part B.
Item               Range          the Best Value
Sn2+               20-30mL/L      24mL/L
W(H2SO4)(98%)       160-185mL/L    175mL/L
Sulfortech Part A      30-60mL/L      40mL/L
STH Additive Sulfolyt   30-80mL/L      40mL/L
Sulfotech Part B       15-25mL/L       20mL/L
Operate temperature   18-25℃         22℃
Cathode-current density  1.3-2 ASD      1.7ASD

The other Blog

评论

发表评论

此博客中的热门博文

1. Let's talk about PCB--- PCB's History

图片
1 . Let's talk about PCB--- PCB's History        Juvtmall  ( a company supply PCB Prototyping , PCBA service  and sell kinds of components, modules  and so on) Development of the methods used in modern printed circuit boards started early in the 20th century. In 1903, a German inventor, Albert Hanson, described flat foil conductors laminated to an insulating board, in multiple layers. Thomas Edison experimented with chemical methods of plating conductors onto linen paper in 1904. Arthur Berry in 1913 patented a print-and-etch method in the UK, and in the United States Max Schoop obtained a patent to flame-spray metal onto a board through a patterned mask. Charles Ducas in 1927 patented a method of electroplating circuit patterns.                                                         ...
阅读全文

3.The design of PCB---General principles

图片
5. General principles of PCB design Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  The  special components layout First, consider the size of PCB: when the size of PCB is too large, the printing line is long, the impedance increases, the anti-noise ability decreases, and the cost increases  too  small,  so  the heat dissipation is not good, and adjacent lines are easily disturbed.   After determining the PCB size,  make sure  the location of the special components.   Finally, l ay  out.the entire components of the circuit   according to the function unit of the circuit . The following principles shall be observed in determining the location of special components: A. To minimize the connection between high frequency components, try to reduce their distribution parameters and electromagnetic interference between th...
阅读全文

6. The design of PCB-- related skills

图片
9. PCB design related skills   Juvtmall  ( a company supply  PCB Prototyping ,  PCBA service  and sell kinds of  components, modules  and so on)  PCB design setting technique The PCB design needs to be set different points  in different stages. In the layout phase, the device layout can be used in the large lattice point . For large devices such as IC and non-locating connectors, the lattice site of 50~100mil can be selected for layout, and the grid point of 25mil can be used for the distribution of passive devices such as resistance capacitance and inductance.  The precision of the large lattice point  is beneficial to the orderliness  and beauty of components. PCB layout rules 1. In general , all components shall be decorated on the same side of the  boards, only the top-level element too close, set  some highly limited and calorific value small devices o n the bottom., such as SMD resistor, SMD...
阅读全文