Blind holes are not necessarily buried HDI circuit board, HDI board generally have blind holes, buried holes are not necessarily, depending on your product is several stages of pressure products.
described as follows:
The first and second six-layer boards are for boards that require laser drilling, meaning HDI boards.
6-layer first-order HDI board refers to the blind hole: 1-2,2-5,5-6. That 1-2,5-6 laser drilling.
The 6th-order second-order HDI board refers to the blind holes: 1-2, 2-3, 3-4, 4-5, 5-6. That is, laser drilling is required twice. First, 3-4 buried holes are drilled, 2-5, and then the first 2-3,4-5 laser drilling hole, followed by the second press 1-6, and then the second drill 1-2,5-6 laser hole. Hole.This shows that the second HDI board after two lamination, laser drilling twice.
In addition, the second HDI board is divided into: the wrong hole second-order HDI board and stacked second-order HDI board, the wrong hole second-order HDI board refers to the blind holes 1-2 and 2-3 are staggered, and stacked second-order HDI Plates refer to blind holes 1-2 and 2-3 stacked together, for example: Blind: 1-3, 3-4, 4-6.
And so on third-order, fourth-order ... are the same.