PCB using new technologies such as BGA and CSP, printed circuit board (PCB) PCB design , PCB design engineers to put forward new challenges and opportunities. Although many people believe that the PCB industry ball grid array (BGA) and chip scale packaging (CSP) is a new emerging PCB technology, but some of the leading electronics manufacturers have introduced or adapted a variation of one or two CSP technologies .
BGA packaging has been developed into a fully compatible with current welding assembly technology. The gate pitch CSP or BGA pitch having a density of 0.5, 0.65, 0.80mm, compared with plastic or ceramic BGA has a relatively wide contact pitch (1.50, 1.27, 1.0mm). Coarse and fine-pitch BGA package than fine pitch IC pin is less susceptible to damage. BGA standard allows to selectively remove the contact points to meet specific I / O requirements. When creating a contact point has been established for the BGA pin layout and distribution of the developer must consider the packing chip design and the circuit chip (die) of size and shape. Other problems encountered when planning pinout is the direction you want the circuit chip. When using the on-board chip suppliers (chip-on-board) technology , usually in the form of circuitry on the chip side up .
Structural elements in industry standards and guidelines is not specified. Each manufacturer will make a particular effort to meet customer -defined structural applications. Depends on the physical characteristics is selected as the material and manufacturing BGA be possible to use a flip-chip (flip chip) or a binding line (wire bond) technology. Because the structure of the circuit chip is adhered to a rigid material, it is bound or attached to the chip holder is usually located in the center , the signal from the wire leads to the chip pads arranged in a matrix ligature spherical contact points .
The overall outline specification allows many array elements of flexibility : If the pin spacing, the contact point matrix form and structure. JEDEC MO-151 defines a plastic BGA Han class. Square outline includes size range , and three contact points 7.0 ~ 50.0mm spacing : 1.50 , 1.27 , and 1.0 mm. Spherical contact points can be unified in the form of an even or odd columns and rows distribution . Although the arrangement must keep all packaging shape symmetry , but allows the component manufacturing location or an area to remove the contact point of contact .
