What should I do if the BGA spacing is too small?

cl17726

What should I do if the BGA spacing is too small? [Copy link]

 

Here is a BGA64 chip. Please refer to the manual for the parameters. As follows. 4mil traces (0.1mm) (4mil spacing) cannot pass. 0.2 holes cannot be placed either. (So FANOUT is not possible) Tried to reduce the PAD size, but the effect was not obvious. How did such a BGA get its traces?

bluefox0919

This is done with blind holes on punched pads, staggered punching and staggered wiring. Then make sure your board factory has this manufacturing process.

btty038

This kind of thing will basically be processed with multilayer board blind holes.  

cl17726

bluefox0919 posted on 2018-12-19 17:57 This is done with blind vias on punched pads, staggered punching and staggered wiring. Then make sure your board factory has this manufacturing process.

However, without blind via technology, the maximum is 4mil/4mil/0.2mm, so this is basically impossible.

qwqwqw2088

The BGA with a pitch of 0.5mm should be able to route. The routing is 4mil, which is 0.1016mm. DSM=0.37,,,, 0.5-0.37=0.13>0.1016. It is difficult to route 4mil in the middle.

qwqwqw2088

Of course, you must be very careful when designing the routing. It seems that it is difficult to find a board manufacturer to make 0.4mm BGA.

cl17726

qwqwqw2088 posted on 2018-12-19 20:57 0.5mm pitch BGA should be able to route, the route is 4mil, that is, 0.1016mm dsm=0.37,,,, 0.5-0.37=0.13>0.1016 4mi in the middle...

4mil outer and 4mil spacing does not seem to be calculated in this way?

qwqwqw2088

cl17726 posted on 2018-12-19 21:00 4mil outer and 4mil spacing doesn't seem to be calculated this way?

BGA center spacing is 0.5mm Dapd here is 0.28 BGA pad 0.37mm pad to pad edge to edge XY direction is 0.13mm 4mil=0.1016mm

qwqwqw2088

The routing needs to be processed with buried blind holes, but buried blind holes can only be made in the area with the maximum diagonal spacing along the edge of the pad.

cl17726

qwqwqw2088 posted on 2018-12-19 21:05 BGA center spacing is 0.5mm Dapd here is 0.28 BGA pad 0.37mm pad to pad edge to edge XY direction are 0.13mm 4mil=0.101 ...

pad edge to pad edge is 0.13, line is 0.1, then the spacing is 0.03, isn't it less than 4mil spacing? Now I have to change PCB factory to make this chip.

qwqwqw2088

cl17726 posted on 2018-12-19 21:14 The pad edge to pad edge is 0.13, the line is 0.1, then the spacing is 0.03, isn't this less than 4mil spacing? Now I have to change PCB factory to make it...

qwqwqw2088

cl17726 posted on 2018-12-19 21:14 The pad edge to pad edge is 0.13, and the line is 0.1, so the spacing is 0.03, isn't it less than 4mil spacing? Now I have to change PCB factory to make it...

The margin is 0.03, which is difficult to do. I have to ask the board factory whether the other party's process can reach it.

bluefox0919

cl17726 posted on 2018-12-19 20:48 However, without blind via technology, the maximum is 4mil/4mil/0.2mm, so this is basically impossible.

You need to make vias in the plate, make blind vias, and increase or decrease the number of board layers by yourself. Routing is not difficult, but it is difficult to find a board factory you can trust.

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