how to do floorplanning for a flip chip

 Hi Gops,

 I'm doing well, thanks!

We usually create the bump lef ourselves. It's pretty simple; you can use a square or an octagon. Here's a quick example for a square bump:

VERSION 5.6 ;
BUSBITCHARS "[" ;
DIVIDERCHAR "/" ;
UNITS
  DATABASE MICRONS 1000 ;
END UNITS

MACRO BUMP
 CLASS COVER BUMP ;
 FOREIGN BUMP -50 -50 ;
 ORIGIN 50 50 ;
 SIZE 100 BY 100 ;
 PIN PAD
    DIRECTION INOUT ;
    USE SIGNAL ;
    PORT
      LAYER M9 ;
        RECT -50 -50 50 50 ;
    END
  END PAD
END BUMP

END LIBRARY
 

A lot of this can depend on your bump gds, technology, etc. but it should be a good starting point.

Bumps definitely have DRC rules. If they are not in the regular design rule manual, sometimes there is a separate FlipChip design rule manual for your process. Check with your foundry. The foundry definitely needs to support flip-chip for you to do your design and they need to provide you at least the gds for the bump.

 You can think of the bump as a single metal for physical design purposes. In reality, if you look at the layout, you will see different layers included, but these are not layers you would see in EDI. A bump can be placed over std cells, macros, etc. The only exception I can think of right now is that some technologies do not want you to place bumps over RAMs. Again, check with your foundry on this one.

I'm not exactly sure what kind of steps you're looking for, but a typical flow is like this: the bump grid is defined by the package. You create the bump grid in EDI according to the package, then you know where you need to place the IO cells to best connect to the bumps. You can either use peripheral IO (looks like a wirebond chip, but instead of the IO pads connecting to wires, they route to bumps using the RDL), or areaIO (special IO cells that can be placed anywhere in the chip). "RDL" is an acronymn for "redistribution layer", but all it really means is the very top metal - the same metal that the bump is in. In some cases, the package may not be defined yet, so you have the freedom to assign the bumps however you like.

Hope that helps,

- Kari

 Hi Gops,

 I'm doing well, thanks!

We usually create the bump lef ourselves. It's pretty simple; you can use a square or an octagon. Here's a quick example for a square bump:

VERSION 5.6 ;
BUSBITCHARS "[" ;
DIVIDERCHAR "/" ;
UNITS
  DATABASE MICRONS 1000 ;
END UNITS

MACRO BUMP
 CLASS COVER BUMP ;
 FOREIGN BUMP -50 -50 ;
 ORIGIN 50 50 ;
 SIZE 100 BY 100 ;
 PIN PAD
    DIRECTION INOUT ;
    USE SIGNAL ;
    PORT
      LAYER M9 ;
        RECT -50 -50 50 50 ;
    END
  END PAD
END BUMP

END LIBRARY
 

A lot of this can depend on your bump gds, technology, etc. but it should be a good starting point.

Bumps definitely have DRC rules. If they are not in the regular design rule manual, sometimes there is a separate FlipChip design rule manual for your process. Check with your foundry. The foundry definitely needs to support flip-chip for you to do your design and they need to provide you at least the gds for the bump.

 You can think of the bump as a single metal for physical design purposes. In reality, if you look at the layout, you will see different layers included, but these are not layers you would see in EDI. A bump can be placed over std cells, macros, etc. The only exception I can think of right now is that some technologies do not want you to place bumps over RAMs. Again, check with your foundry on this one.

I'm not exactly sure what kind of steps you're looking for, but a typical flow is like this: the bump grid is defined by the package. You create the bump grid in EDI according to the package, then you know where you need to place the IO cells to best connect to the bumps. You can either use peripheral IO (looks like a wirebond chip, but instead of the IO pads connecting to wires, they route to bumps using the RDL), or areaIO (special IO cells that can be placed anywhere in the chip). "RDL" is an acronymn for "redistribution layer", but all it really means is the very top metal - the same metal that the bump is in. In some cases, the package may not be defined yet, so you have the freedom to assign the bumps however you like.

Hope that helps,

- Kari