As Surface Mount Technology(SMT) has improved many packages have decreased in size.
Additionally, there is a variety of different SMT packages for integrated circuits dependent upon the interconnectivity required, the technology being used, and a variety of other factors.
Fortunately, SMT Package and components are largely standardized in size, allowing for component consistency.
These standards are defined by the Joint Council for Electronics Engineering to simplify development processes for:
- PCB designers
- Component manufacturers
- And companies that manufacture and use SMT fabrication equipment
Resistor Component Packaging
Resistance component packaging
Small surface mount resistors are used by the billion in all forms of mass-produced electronic equipment.
Resistors are typically very small cuboid devices and they are normally manufactured to conform to the industry-standard sizes.
Sometimes surface mount resistors are also used as MELF packages (Metal Electrode Leadless Face).
The main advantage of using MELF instead of standard SMD packages is the lower thermal coefficient and better stability.
Capacitor Component Packaging
Capacitor component packaging
Small surface mount capacitors are used by the billion in all forms of mass-produced electronic equipment.
Surface mount capacitors are normally small rectangular cuboids the dimensions of which normally manufactured to conform to the industry-standard sizes.
SMCD capacitors may use a variety of technologies including multilayer ceramic, tantalum, electrolytic, and some other less widely used varieties.
IC Component Packaging
IC Component packaging
IC packaging is the last stage in the production of semiconductor devices. During this stage, the semiconductor block gets covered in a package that protects the IC from potentially damaging external elements and the corrosive effects of age.
The package is essentially an encasement designed to protect the block and also to promote the electrical contacts that deliver signals to the circuit board of an electronic device.
What is SMT Package
Surface mounting technology is a method of mounting and mounting a conventional electronic component on a substrate in the form of an electronic chip.
And it is changed from a conventional method of punching and inserting into a printed circuit board to a method of instantly adhering to the substrate.
It is a technology that reduces the area of the board and switches from a single-area layer board to a multi-layer board.
In recent years, the “SMT Package “has become the mainstream of board mounting due to the increasing size and density of boards.
When some products adopt both the SMT process and IMT process, usually the SMT process is completed first and then the IMT stage is entered, but in this case, one extra process is required, so the cost is high.
Due to market demands and rising labor costs, IMT is about to be replaced by SMT.
Most of the fields where portability is required, such as mobile phones, PDAs, and GPS, use the SMT process.
For some products that use high voltage and large currents, the ratio of SMD adoption is low due to special parts.
What is Surface Mount Technology
When you first hear this word, what is it?
It can be said that it literally means a technology to mount something on the surface.
As it is a term used in the electronics industry, the surface refers to a PCB board and it is a technology that solders a specific chip on the PCB.
Advantages of SMT Package
SMT Package is a market requirement and has the effect of indirect cost reduction for the following reasons.
Since the size of the parts that can be made smaller and thinner is smaller, the required board area can be reduced.
SMT Package is different from IMT, where the components are placed directly and the mounting part is soldered onto the board, so the pins are inserted into the holes and soldered.
Therefore, the cost of the board can be reduced by reducing the size of the board, and the processing cost of drilling is not required.
In addition, since there is no need to drill holes, the pattern layout work on the board becomes more efficient and the number of layers on the board can be reduced.
For example, in the case of IMT design, if you change to the SMT method instead of four layers, it will fit in a two-layer board. Of course,two-layer boards are cheaper than four-layer boards.
Suitability of SMT Package
SMD for mass production SMD is technically suitable for automated mass production.IMT parts also have automatic mounting devices such as:
- Horizontal inserters
- Vertical inserters
- Variant inserters
- IC inserters
But the production volume per unit time is not as good as SMD.
As the production volume per unit time increases, so does the production cost.
SMT Package Dominant Parts
Chip parts such as:
- Resistors
- Capacitors
- Transistors
- Coils
Semiconductor devices such as flat package ICs and functional parts such as switches and connectors for surface mount are included in surface mount parts.
These parts are made in shapes and sizes suitable for automatic mounting and are standardized for compatibility.
The base (bottom) surface-mounted part is made to be compatible with the solder material (adhesive).
So it is mounted using the floor dip method or the floor solders method.
Methods of automatically mounting parts by these methods include:
- A batch mounting method
- One by one mounting method
- And an in-line mounting method used for small substrates such as ICs, which occurred in the early 1970s.
Various SMT Package Techniques
Different brands have different SMT Package techniques for making chip-mounted machines on the SMT line.
However, all stages follow a general standard, including 4 steps:
- Scanning welding alloys: The solder paste has a paste form, high adhesion; the composition varies depending on the technology and the object of the welding. The solder paste sweeps through the holes of a metal mask (metal mask or stencil) placed on the PCB to avoid sticking to undesirable places. After that, move on to the mounting part
- Chip mounting, IC mounting: The machine automatically removes components from the conveyor belt or tray and places them in the corresponding position that has been scanned with solder paste. After the solder paste is dried, the PCB is flipped over and the mounting process is repeated. The new SMT technology also allows attaching components at the same time on both sides
- Heating – Cooling: In the drying oven, PCBs pass through the areas with increasing temperatures so that the components can adapt. At a large enough temperature, the solder paste melts, glues components onto the PCB. Then they are washed with a number of chemicals, solvents, and water to clean the welding material and then use compressed air to dry quickly.
- Checking and fixing errors: In step 2 we can use optical or X-ray AOI (automated Optical Inspection) machines. These devices allow detecting position errors, contacting errors of components, and soldering paste on the surface of the printed circuit.