I'm working on a high speed board design containing transimpedance amplifiers. Here's the schematic below:
Right now, my layout seems fine, but I'm concerned about placing vias to connect ground planes. This is a 6-layered board, with all planes designated as ground planes. I was told that you should place ground vias to connect the ground planes together in order to create a stronger connection to ground between all the layers and/or possibly reduce the inductance of the overall board to allow for faster signaling. Given the layout limitations, the image below showcases the board thus far:
Does the size of the via really matter, or is it better to just have as many vias as possible wherever you can? Are there some recommended areas where I should place more vias? Is this perhaps overkill with the vias? I'm using a coaxial connector for the output of the signal, so I placed tiny vias around it close to the no fill zones.
EDIT: Here's another picture of the board, but horizontal rather than vertical. I apologize for the quality of the image. I can't seem to do any better. The ground vias are completely surrounded by the ground planes (in the images, only the top and bottom ground planes are shown to make it less confusing). You can see an example of them at the coaxial connector, with the center pin surrounded by the no fill zone in the bottom plane. The four ground connectors surrounding it are filled by the ground plane while the center pin doesn't touch it. I don't know if this is a good explanation, but please let me know if I can be clearer about it. Other examples of ground vias include the square of vias in the center of the board.
EDIT: Someone mentioned that it would probably be clearer if I posted the board as separate layers for easier viewing:
Inner Layer 1:
Inner Layer 2:
Inner Layer 3:
Inner Layer 4: