Hard IP blocks with physically bidirectional passageways
Hard IP blocks, such as SerDes chips, are designed with keepout zones beneath the surface interconnects, the keepout zones being spaces within the chip where there is no circuitry. Connections can be formed between surface interconnects on an under surface of the SerDes chip that faces the host die, and surface interconnects on an upper surface of the SerDes chip that interfaces without external devices. Accordingly, redistribution layers routing around an outer periphery of the SerDes chip are no longer needed, and the resistive capacitive load remains low so as not to adversely impact transmitted signals.
1. A method of fabricating a hard IP block, comprising:
defining one or more keepout zones for the hard IP block comprising a serializer/deserializer (SerDes);
forming a base for the hard IP block, the base having a top surface and a bottom surface;
forming a circuitry layer on the top surface of the base, the circuitry layer comprising circuitry for the SerDes in areas around the one or more keepout zones such that each of the keepout zones is exclusive of the circuitry;
forming through-hole interconnects through the keepout zones; and
hybrid direct bonding the hard IP block to a host substrate such that a surface of the hard IP block contacts a top surface of the host substrate without an intervening material therebetween.
2. The method of claim 1 , wherein defining the one or more keepout zones comprises laying out components of the hard IP block using an automated or semi-automated process.
3. The method of claim 2 , wherein defining the one or more keepout zones comprises implementing a rule in a computer-assisted process that identifies defined placement for a surface interconnect and automatically creates a keepout zone beneath the surface interconnect.
4. The method of claim 1 , wherein forming the base for the hard IP block comprises depositing a dielectric in an additive process.
5. The method of claim 1 , wherein positioning the circuitry on the base in the areas around the one or more keepout zones comprises positioning the circuitry such that it does not extend into any of the defined keepout zones.
6. The method of claim 1 , wherein positioning the circuitry comprises forming surface interconnects at one or both of the top and bottom surfaces of the hard IP block in relation to the defined one or more keepout zones.
7. The method of claim 6 , wherein forming the surface interconnects comprises positioning each surface interconnect in longitudinal alignment with a corresponding one of the one or more keepout zones.
8. The method of claim 7 , wherein the surface interconnects are one of bumps, pads, or pillars.
9. The method of claim 1 , wherein the through-hole interconnects extend from the bottom surface of the base to the top surface, beyond the circuitry.
10. The method of claim 1 , wherein forming the through-hole interconnects comprises depositing copper within a portion of the keepout zones.
11. The method of claim 1 , further comprising temporarily filling the keepout zones with a temporary material, the temporary material serving as guideposts for positioning the circuitry.
12. The method of claim 11 , further comprising removing the temporary material prior to, or during, the forming of the through-hole interconnects.
13. The method of claim 12 , wherein removing the temporary material comprises partially removing the temporary material.
14. The method of claim 1 , wherein hybrid direct bonding the hard IP block to the host die substrate comprises bonding the hard IP block to the host substrate in a face-to-face configuration, wherein in the face-to-face configuration a front of the hard IP block is bonded to a face of the host substrate.
15. The method of claim 1 , wherein hybrid direct bonding the hard IP block to the host substrate comprises bonding the hard IP block to the host substrate in a face-to-back configuration, wherein in the face-to-back configuration a back of the hard IP block is bonded to a face of the host substrate.
16. The method of claim 15 , wherein hybrid bonding the hard IP block to the host substrate comprises using a non-adhesive hybrid bonding technique.
17. A method of forming a 3D structure, comprising:
forming a hard IP block comprising a base having a top surface and a bottom surface, the hard IP block comprising a serializer/deserializer (SerDes);
forming a circuitry layer within the base adjacent the top surface, the circuitry layer comprising circuitry for the SerDes;
forming one or more keepout zones within the circuitry layer, the one or more keepout zones defining spaces exclusive of the circuitry;
forming one or more through-hole interconnects, each of the one or more throughhole interconnects extending from the top surface of the hard IP block, longitudinally through a corresponding one of the one or more keepout zones, and to the bottom surface of the hard IP block;
forming one or more surface interconnects, each of the one or more surface interconnects being positioned at the bottom surface of the hard IP block in longitudinal alignment with a corresponding one of the one or more keepout zones and being electrically connected to a corresponding one of the one or more through-hole interconnects;
hybrid direct bonding the hard IP block with a host substrate such that a surface of the hard IP block contacts a top surface of the host substrate without an intervening material therebetween; and
coupling a second layer device to the one or more surface interconnects at the bottom surface of the hard IP block.
18. The method of claim 17 , wherein direct bonding the hard IP block with the host substrate comprises using a non-adhesive hybrid bonding technique.