RF choke device for integrated circuits
Among other things, one or more techniques and systems for selectively filtering RF signals within one or more RF frequency band are provided. In particular, an RF choke, such as a 3D RF choke or a semi-lumped RF choke, configured to selectively filter such RF signals is provided. The RF choke comprises a metal connection line configured as an inductive element for the RF choke. In an example, one or more metal lines, such as a metal open stub, are formed as capacitive elements for the RF choke. In another example, one or more through vias are formed as capacitive elements for the RF choke. In this way, the RF choke allows DC power signals to pass through the metal connection line, while impeding RF signals within the one or more RF frequency bands from passing through the metal connection line.
1. A system for selectively filtering a radio frequency (RF) bandwidth, comprising:
a 3D RF choke configured to selectively filter the RF bandwidth, the 3D RF choke comprising:
a metal RF line connecting an RF input port to an RF output port;
a metal connection line connecting to a DC power source at a first location and connecting to the metal RF line at a second location; and
a first signal through via connected to the metal connection line at a third location, the third location between the first location and the second location.
2. The system of claim 1 , comprising:
a metal line connected to the metal connection line at the third location and the first signal through via indirectly connected to the metal connection line at the third location through the metal line.
3. The system of claim 1 , comprising:
the metal RF line and the metal connection line disposed between a passivation layer and a substrate.
4. The system of claim 3 , comprising:
a first ground through via extending through the passivation layer, wherein the first signal through via and the first ground through via define a capacitive element.
5. The system of claim 3 , the substrate comprising a molding compound.
6. The system of claim 1 , comprising:
a metal line connected to the metal connection line at the third location and a bottom surface of the first signal through via in contact with the metal line; and a second metal line in contact with a top surface of the first signal through via.
7. The system of claim 1 , comprising:
a bottom surface of the first signal through via in contact with the metal connection line.
8. The system of claim 1 , comprising:
a first ground through via connected to a ground point, wherein the first signal through via and the first ground through via define a capacitive element.
9. The system of claim 8 , the 3D RF choke comprising:
a second capacitive element comprising:
a second ground through via; and
a second signal through via connected to the metal connection line through a metal line.
10. A system for selectively filtering a radio frequency (RF) bandwidth, comprising:
a 3D RF choke configured to selectively filter the RF bandwidth, the 3D RF choke comprising:
a metal connection line configured as an inductive element, the metal connection line connecting to a DC power source at a first location of the metal connection line, the metal connection line connecting to a metal RF line at a second location of the metal connection line, the metal RF line connecting an RF input port to an RF output port; and
a capacitive element comprising:
a first ground through via connected to a ground point; and
a first signal through via connected to the metal connection line at a third location of the metal connection line.
11. The system of claim 10 , the metal connection line comprising a first configuration value based upon an impedance control factor for the inductive element.
12. The system of claim 10 , the third location between the first location and the second location.
13. The system of claim 10 , the 3D RF choke comprising:
a second capacitive element comprising:
a second ground through via; and
a second signal through via connected to the metal connection line through a metal line.
14. The system of claim 13 , the metal line configured as a first post passivation interconnection (PPI) layer formed underneath the second signal through via, and the 3D RF choke comprising:
a second PPI layer formed above the second signal through via.
15. The system of claim 14 , the 3D RF choke configured according to a meandered structure, the meander structure comprising the first PPI layer, the second PPI layer, and at least one of the first signal through via, the second signal through via, the first ground through via, or the second ground through via.
16. The system of claim 14 , the 3D RF choke configured according to a vertical ring structure, the vertical ring structure comprising the first signal through via, a first metal line within the first PPI layer, a second metal line within the second PPI layer, the second signal through via, and a third metal line within the first PPI layer, the third metal line connecting the second signal through via to the metal connection line, the first signal through via and the second signal through via connected by the second metal line.
17. The system of claim 10 , wherein a height value, a diameter value, or a pitch value between the first ground through via and the first signal through via is based upon an impedance control factor for the capacitive element.
18. A method for forming an RF choke, comprising: forming a metal connection line between a DC power source at a first location of the metal connection line and a metal RF line at a second location of the metal connection line, the metal connection line formed as an inductive element for the RF choke;
forming a metal line connecting to the metal connection line at a third location of the metal connection line between the first location and the second location;
forming a capacitive element for the RF choke, the capacitive element comprising a first signal through via over the metal line and a first ground through via;
connecting the first ground through via to a ground point; and
connecting the first signal through via to the metal line.
19. The method of claim 18 , comprising:
forming a second capacitive element for the RF choke, the second capacitive element comprising a second signal through via and a second ground through via;
connecting the second ground through via to a second ground point; and
connecting the second signal through via to the metal line.
20. The method of claim 18 , comprising:
forming a first post passivation interconnection (PPI) layer underneath the first signal through via, the first PPI layer comprising the metal line; and
forming a second PPI layer above the first signal through via.