Blind orifice plate making knowledge
With the development of high-density and high-precision electronic products, the same requirements are imposed on circuit boards. The most effective way to increase the density of pcb is to reduce the number of through holes, and to accurately set blind holes and buried holes.
1. Blind hole definition a: In contrast to the through hole, the through hole refers to the hole through which each layer is drilled, and the blind hole is the non-drilled through hole. (Illustration, eight-layer board example: through hole, blind hole, buried hole) b: blind hole subdivision: blind hole (BLIND HOLE), buried hole BURIED HOLE (outer layer is not visible); c: from the production process Distinction: The blind hole is drilled before pressing, and the through hole is drilled after pressing.
2. Production method: a: drill belt:
(1): Select reference point: Select the through hole (ie one hole in the first drill belt) as the unit reference hole.
(2): Each blind hole drill belt needs to select a hole, and mark the coordinates of its relative unit reference hole.
(3): Note which layer corresponds to which drill belt: the unit hole map and the drill head table must be marked, and the front and rear names must be consistent; the split hole map cannot be represented by abc, and the front is 1st, 2nd. The situation indicated.
***Note that when the laser hole is nested with the inner buried hole, that is, the holes of the two drill belts are in the same position, the position of the laser hole is required to ensure the electrical connection. (Illustration 9430)
B: Production of pnl board edge process hole:
Ordinary multi-layer board: the inner layer is not drilled;
(1): rivets gh, aoi gh, et gh are all etched after the slab (beer)
(2): target hole (drilling gh) ccd: outer layer needs to be smashed copper, x-ray machine: directly shot, and note that the long side is at least 11 inches. (11228)
Blind hole plate:
All tooling holes are drilled, pay attention to the rivet gh; beer is required to avoid misalignment.
(aoi gh is also a beer), the production of pnl board needs to be drilled to distinguish each board.
3. Film modification:
(1): Note that the film is positive, negative:
General principle: the thickness of the plate is greater than 8 mil (without copper).
The thickness of the plate is less than 8 mil (without copper) and the negative film process (thin plate);
When the line is thick, the copper thickness at d/f should be considered, not the thickness of the bottom copper.
Blind hole ring can be 5mil, no need to do 7mil.
The inner layer independent pad corresponding to the blind hole needs to be retained.
Blind holes cannot be made without ring holes.
The buried plate is consistent with the conventional double-panel approach.
A blind hole plate, that is, one side is the outer layer:
Positive film process: need to do single-sided d/f, pay attention to the wrong surface (when the double-sided copper is inconsistent); when d/f exposure, the light copper surface is covered with black tape to prevent light transmission.
Because the blind hole plate is made more than twice, the electric power is very thick and thick. Therefore, the electric control board is thick and thick, and the thickness of the thick copper plate is indicated after etching.
After pressing the plate, use the x-ray machine to shoot the target hole for the multi-layer board.
Negative film process: for thin plates (<12mil with copper) because it can not be produced in the drawing of electric pull, it must be produced in water gold, and water gold pull can not be divided into surface current, so it is impossible to do single-sided non-current or hit according to mi requirements. A small current, such as the positive film process, often results in a single-sided copper thick and thick, resulting in etching difficulties, young lines, so such boards need to take the negative process.
5. Through holes and blind holes have different drilling order, and the deviations during production are inconsistent;
The blind hole plate is more likely to be deformed, and the horizontal and vertical material is difficult to control the alignment of the multi-layer plate and the pipe position, so only the horizontal material or the straight material is opened when the material is opened.
6. Laser drill:
LASER DRILL is a kind of blind hole and has its own characteristics:
Pore size: 4-6 mil
Pp thickness must be <= 4. 5mil, calculated according to the aspect ratio <=0.75:1
There are three types of pp: LDPP 106 1080; FR4 106 1080; RCC.
7. How to define a buried plate requires a resin plug hole:
a. H1(CCL): H2(PP) 〉=4 thickness ratio
b. HI(CCL) 》32 MIL
c. 2OZ and 2OZ laser buried plate; high thickness copper, high tg plate needs to be sealed with resin.
The board process of this type of board should pay attention to first sealing the hole with resin to avoid serious damage to the line.
Soft and hard bonding board production process and application软硬结合板制作工艺及应用
Soft and hard bonding board production process and application
As a special interconnect technology, flex-rigid multilayer printed boards can reduce the assembly size and weight of electronic products, avoid wiring errors, achieve three-dimensional assembly under different assembly conditions, and have light and thin Short, small, has been widely used in computers, avionics and military electronic equipment, but rigidly printed boards also have the disadvantages of complex processes, high production costs and difficult to change and repair.
This paper mainly discusses the improvement of the rigid-flex multilayer printed board laminate and the outer layer imaging, and discusses the production of rigid-flex printed board.
Second, rigidly printed board structure:
Rigid-flex printed boards are two (or more) rigid outer layers bonded to a flexible printed board. The circuitry on the rigid layer and the circuitry on the flexible layer communicate with each other through the metallized holes. Each rigid flexible printed board has one or more rigid zones and one or more flexible zones. Figure 1 is a schematic view of the structure of a typical eight-layer rigid-flex printed board.
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