nd includes through vias 324 to enable communications between the PCB 310 and a die 330. The die 330 is coupled to the packaging substrate 320 through an interconnect structure 332 such as bumps or pillars.
A voltage regulator 340 is coupled to the PCB 310 through a packaging connection 342. The voltage regulator 340 conventionally couples to discrete passive components such as inductors and capacitors mounted on the PCB 310. Low inductance passes (not shown) provide power from the voltage regulator 340 to the die 330. The low inductance passes are restricted in location on the PCB 310, which also restricts location of the voltage regulator 340. Thus, the distance between the voltage regulator 340 and the die 330 has a fixed minimum based on the PCB 310.
For the reasons discussed above including large voltage drop between the voltage regulator and the die, slow response times due to distance from the die to the voltage regulator, increased PCB size, the use of large decoupling capacitors, and the use of additional pins on the die to communicate with the voltage regulator, locating a voltage regulator on the PCB separate from the packaging substrate may not provide sufficient voltages to the die for proper operation. If the supply voltage drops below an acceptable level, the circuits on the die may output incorrect results or stop working completely.
According to one embodiment, a voltage regulator may be integrated into the die. An integrated voltage regulator in the die does not use additional pins for communicating with the die. Instead, communication occurs through interconnects in the die. The integrated voltage regulator is also closer to the die resulting in quicker response times to current transients and smaller decoupling capacitors to filter the output of the voltage regulator. Furthermore, passive components may be embedded in the packaging substrate to reduce area on the die occupied by the voltage regulator.
Passive components may be embedded in a packaging substrate or a PCB. Embedding the passive components maintains a short path having low inductance from the voltage regulator to the die. Further, the voltage regulator control loop bandwidth is increased by the higher switching frequency and shortened feedback path between the voltage regulator and the die.
Larger inductance values are achieved by embedding passive components in comparison to conventional parasitic air-core inductors in packaging substrate routing or PCB routing. Embedding passive components also reduces die size by reducing or eliminating discrete passive components of the voltage regulator, which may otherwise be located side-by-side with the die.
FIG. 4 is a cross-sectional view illustrating an exemplary voltage regulator on a die according to a first embodiment. An IC product 400 includes a packaging substrate 420 coupled to a PCB 410 through a packaging connection 422 such as bumps or pillars. The packaging substrate 420 includes embedded passive components that may store energy in magnetic or electric form. For example, an embedded inductor 450 and an embedded capacitor 460 are at least partially embedded in the packaging substrate 420. The embedded inductor 450 and/or the embedded capacitor 460 may use embedded die substrate (EDS) technology. In one embodiment, the embedded capacitor 460 may have capacitance values in the hundreds of nanoFarads and provide decoupling capacitance to a die 430. The die 430 is coupled to the packaging substrate 420 through an interconnect structure 432 such as bumps or pillars.
Manufacturing the embedded inductor 450 and the embedded capacitor 460 in the packaging substrate 420 may use a lamination process according to one embodiment. For example, the packaging substrate 420 may start as a core with two internal layers separated by a thick dielectric layer. Holes are placed in the substrate using a laser drilling process and tape placed on a backside of the core. The holes are filled to form the embedded inductor 450 and the embedded capacitor 460, and a top side of the core is laminated. The embedded