Category: Business/Financial Management>Business Documents
Problem Description:
What is the process flow of any electronic or industrial product? And what is the process of every electronic or industrial product? What manufacturing techniques and materials are used in each step?
Brother, thank you!! Urgent need!!!!!!!!!!!!
Analysis :
Introduce two, I hope they can help you
The first one: 1.1 The role played by PCB
The function of PCB is to provide the first-level structure A base where assembled components are joined with other necessary electronic circuit parts to form a module or finished product with a specific function. Therefore, PCB plays the role of integrating and linking all functions in the entire electronic product. Therefore, when electronic products often malfunction, the PCB is often questioned first. Figure 1.1 is a schematic diagram of the hierarchy of electronic components.
1.2 The evolution of PCB
1. As early as 1903, Mr. Albert Hanson pioneered the use of the "Circuit" concept in telephone switching systems. It uses metal foil to cut into line conductors, adheres them to paraffin paper, and also affixes a layer of paraffin paper on top, becoming the prototype of today's PCB structure. See Figure 1.2
2. By 1936, Dr Paul Eisner truly invented the PCB manufacturing technology and issued a number of patents. Today's print-etch (photoimage transfer) technology follows its invention.
1.3 PCB types and manufacturing methods
Diversification in materials, layers, and manufacturing processes to suit different electronic products and their special needs. The following summarizes some common distinction methods to briefly introduce the classification of PCB and its manufacturing methods.
1.3.1 PCB types
A. Classified by material
a. Organic material
Phenolic resin, glass fiber/epoxy Resin, Polyimide, BT/Epoxy, etc. all belong to this category.
b. Inorganic materials
Aluminum, Copper-invar-copper, ceramic, etc. all belong to this category. Mainly based on its heat dissipation function
B. Distinguish the finished product by software and hardware
a. Rigid PCB
b. Flexible PCB, see Figure 1.3
p>c. Rigid-Flex PCB of soft and hard board is shown in Figure 1.4
C. Divided by structure
a. Single panel is shown in Figure 1.5
b. Double-sided board, see Figure 1.6
c. Multi-layer board, see Figure 1.7
D. Divided by use: communications/consumable electronics/military/computer/semiconductor/electrical measurement Board..., see Figure 1.8 BGA.
There is another type of injection molded three-dimensional PCB, which is not introduced here because it is rarely used.
1.3.2 Introduction to manufacturing methods
A. Subtractive method, the process is shown in Figure 1.9
B. Additive method, which can be divided into semi-additive and semi-additive Full additive method, see Figure 1.10 1.11
C. There are other advanced processes that have evolved in response to changes in IC packaging. This CD only mentions them but does not introduce them in detail because many of them are still confidential. It is also not easy to obtain, or it is not mature enough. This CD takes the traditional negative multilayer board manufacturing process as the main axis, introduces each process in a simple and easy-to-understand manner, and then discusses the future PCB trend with the concept of advanced technology.
2.3.1 Data that customers must provide:
When an electronics factory or assembly factory entrusts PCB SHOP to produce bare boards, the following data must be provided for production. See the material number data sheet - for pre-production design use.
The data in the above table are necessary items. Sometimes customers will provide a sample, a parts drawing, and a warranty (guaranteeing the original materials used in the manufacturing process). Materials, consumables, etc. do not contain certain toxic substances), etc. Manufacturers must judge the importance of these additional data on their own to avoid missing business opportunities.
2.3.2. Data review
Faced with so much data, the next work procedures and key points for the pre-production design engineer are as follows.
A. Review the customer's product specifications to see if the factory's process capabilities are available. For review items, see the process capability inspection list for the accepted material number.
B. Raw material requirements (BOM-Bill of Material)
After reviewing and analyzing the above data, the brand, type and specification of the raw materials will be determined by the development of BOM. The main raw materials include: substrate (Laminate), film (Prepreg), copper foil (Copper foil), solder mask (Solder Mask), text ink (Legend), etc. In addition, the customer's requirements for Finish will affect the selection of the process. Of course, there will be different material requirements and specifications, such as: soft, hard gold, spray tin, OSP, etc.
The table summarizes the factors that may affect the selection of raw materials according to customer specifications.
C. The above is a review of new data. After the review is completed, samples will be produced. If it is old data, you must check whether there is an ECO (Engineering Change Order) before reviewing it.
D. Typesetting
The size selection of typesetting will affect the profit rate of the material number. Because the substrate is the main raw material cost (optimizing layout can reduce plate waste); and proper layout can increase productivity and reduce defective rates.
Some factories believe that fixing certain work sizes can meet maximum productivity, but the cost of raw materials increases a lot. The following are some directions to consider:
General production costs, direct and indirect raw materials It accounts for about 30 to 60 of the total cost, including substrate, film, copper foil, solder mask, dry film, drill bits, heavy metals (copper, tin, lead), chemical consumables, etc. The consumption of these raw materials is directly related to whether the layout size is appropriate. When most electronics factories do circuit layout, they will do a continuous design to achieve the highest productivity during assembly. Therefore, pre-production designers of PCB factories should communicate closely with customers so that the size of the contiguous Layout can be optimally utilized when typesetting into a working PANEL. To calculate the most appropriate layout, several factors must be considered.
a. Minimum number of knives and maximum usage rate for base material cutting (cutting method and edge grinding must be taken into consideration).
b. The size of copper foil, film and dry film must be well matched with the size of the working PANEL to avoid waste.
c. When connecting pieces, the minimum size between pieces, and the minimum size left on the edge of the board for tools or alignment systems.
d. The possible maximum size limit or effective work area size of each process.
e. Different product structures have different production processes and different layout restrictions, for example, gold finger boards , the layout spacing must be larger and the direction must be considered, and the test fixtures or test order requirements are also different. Larger working sizes can meet greater productivity, but the cost of raw materials increases a lot, and the equipment's process capabilities also need to be improved. How to achieve a balance point, design criteria and the experience of engineers are very important.
2.3.3 Start the design
After all the data has been verified, start the division of labor design:
A. Process decision (Flow Chart) determined by data review After analysis and confirmation, the design engineer determines the most appropriate process steps. The production process of traditional multi-layer boards can be divided into two parts: inner layer production and outer layer production. The following icons illustrate several representative processes for reference. See Figure 2.3 and Figure 2.4
B. CAD/CAM Assignment
a. Enter the Gerber Data into the CAM system used. At this time, apertures and shapes must be defined. Currently, there are many PCB CAM systems that accept the IPC-350 format. Some CAM systems can generate appearance NC Routing files, but general PCB Layout design software does not generate this file. Some professional software, either independently or in conjunction with NC Router, can set parameters and directly output the program.
Shapes include circles, squares, rectangles, and more complex shapes, such as inner thermal pads, etc. . When starting the design, the relationship between Aperture code and shapes must be clearly defined first, otherwise the subsequent series of designs will not be possible.
b. Check list during design
After reviewing the check list, you can know the possible yield rate and cost estimate of the production material number.
c. Working Panel layout notes:
- PCB Layout engineers will make some auxiliary marks for reference to help remind or pay attention to certain matters during design, so it is necessary Remove it before entering layout. The following table lists several projects and their impacts.
- The size selection of typesetting will affect the profit rate of the material number. Because the substrate is the main raw material cost (optimizing layout can reduce plate waste); and proper layout can increase productivity and reduce defective rates.
Some factories believe that fixing certain work sizes can meet maximum productivity, but the cost of raw materials increases a lot. The following are some directions to consider:
General production costs, direct and indirect raw materials It accounts for about 30~60% of the total cost, including substrate, film, copper foil, solder mask, dry film, drill bits, heavy metals (copper, tin, lead, gold), chemical consumables, etc. The consumption of these raw materials is directly related to whether the layout size is appropriate. When most electronics factories do circuit layout, they will do a continuous design to achieve the highest productivity during assembly. Therefore, pre-production designers of PCB factories should communicate closely with customers so that the size of the contiguous Layout can be optimally utilized when typesetting into a working PANEL. To calculate the most appropriate layout, several factors must be considered.
1. The minimum number of knives and maximum usage rate for cutting the substrate (the cutting method and edge grinding must be taken into consideration).
2. The size of copper foil, film and dry film must be well matched with the size of the working PANEL to avoid waste.
3. When connecting pieces, the minimum size between pieces, and the minimum size left on the edge of the board for tools or alignment systems.
4. The possible maximum size limit or effective work area size of each process.
5. Different product structures have different production processes and different layout restrictions, for example, gold finger boards, The layout spacing must be larger and the direction must be considered, and the test fixtures or test order requirements are also different.
Larger working size can meet greater productivity, but the cost of raw materials increases a lot, and the equipment process capability also needs to be improved. How to achieve a balance point, design criteria and engineer experience are very important .
- During the typesetting process of the working panel, the following matters must be considered to ensure a smooth process. The table typesetting precautions are listed below.
d. Film and program:
- After the film Arork is edited and typed in the CAM system, the film is drawn by a laser plotter (Laser Plotter) in conjunction with the D-Code file. . The negatives that need to be drawn include the inner and outer lines, the outer solder mask, and the text negatives.
As circuit density is getting higher and tolerance requirements are getting stricter, film size control is currently a major issue for many PCB manufacturers. The table is a comparison table between traditional film and glass film. The proportion of glass negatives used has been increasing. Film manufacturers are also actively researching alternative materials to achieve better dimensional stability. For example, dry-process bismuth metal negatives.
Generally, the following precautions should be taken when storing and using traditional negatives:
1. Environmental temperature and relative temperature control
2. The adaptation time for taking out and using new films
3. Methods of taking, transferring and storing
4. Cleanliness of storage or operating areas
- Program
Contains primary and secondary hole drilling programs, as well as contour routing programs. The NC Routing program generally needs to be processed separately
e. DFM-Design for manufacturing .Pcb Most lay-out engineers don't know much about the PCB production process and the things that need to be paid attention to in each process. Therefore, when laying-out circuits, they only consider the electrical properties, logic, size, etc., and rarely take other things into consideration. Therefore, PCB pre-production design engineers must correct some circuit characteristics from the considerations of productivity, yield, etc., such as the circular wiring PAD is modified into a teardrop shape, as shown in Figure 2.5, in order to prevent the PAD hole from being misaligned during the manufacturing process. Maintain minimum backing ring width.
However, the corrections made by pre-production engineers sometimes affect the characteristics or even performance of the customer's product, so we have to be cautious. PCB factories must have a set of specifications compiled based on the characteristics of the in-factory process. In addition to improving product yield and productivity, it can also be used as a communication language with PCB line lay-out personnel, see Figure 2.6.
C. Tooling
Refers to AOI and electrical measurement Netlist files. AOI generates data acceptable to the AOI system from the CAD reference file and contains tolerances, while electrical measurement Netlist files are used to create electrical measurements. Test fixture.
Second
Introduction to the process flow of circuit boards
1. Double-sided board process:
Copper-clad laminate (CCL) cutting (Cut) → drilling (Drilling) → copper immersion (PTH) → full-board copper plating (Panel Plating) → pattern transfer (Pattern) ink Or dry film → Pattern plating → Etch → Semi-inspection IQC → Screen printing solder mask ink and character ink (SS) or solder mask dry film → Hot air leveling or tin spraying (HAL) → Pounching ) → Finished Quality Inspection (FQC) → Electrical Test E-TEST → Packaging (Packaging)
2. Multilayer board process flow:
Inner layer copper clad laminate (CCL) copper foil (Copper Foil) cutting (Cut) → inner layer pattern production (Inner-layer Pattern) → inner layer etching (Inner-layer) Etch) → inner layer black oxide (Black-oxide) → lamination or laminating process → drilling (Drilling) → copper immersion (PTH) → full board copper plating (Panel Plating) → outer layer etching (Outer-layer Etch) → Semi-inspection IQC → Silk screen solder mask ink and character ink (SS) or solder mask dry film → Hot air leveling or spray tin (HAL) → Appearance (Pounching) → Finished inspection (FQC) → Electrical test E-TEST → Packaging (Packaging)