 inductor 450 may be, for example, non air-core inductors to obtain higher inductance values than air-core inductors. Next, tape is peeled off the back side of the core, and the back side of the core is laminated. The inductance of the embedded inductor 450 and the capacitance of the embedded capacitor 460 are selected, in part, from parameters including a supply voltage of the die 430 and an operating frequency of the die 430. Passive components located in the packaging substrate 420 may use thicker copper than passive components located in a die and thus have smaller losses and a higher quality (Q) factor.
An active portion of a voltage regulator 440 is fabricated on the die 430 and includes, for example, a driver stage, a feedback stage, and/or a digital controller. The active portion of the voltage regulator 440 communicates with the embedded inductor 450 through an electrical path 426. An electrical path 427 couples the embedded inductor 450 to the embedded capacitor 460. An electrical path 428 couples the embedded capacitor 460 to the die 430. An electrical path 424 enables communication from the die 430 to the PCB 410. The electrical path 424 may be used, for example, to provide voltage to the active portion of the voltage regulator 440. That is, regulated voltage provided to the die 430 passes through the electrical path 424 to the active portion of the voltage regulator 440, then to the embedded inductor 450, and the embedded capacitor 460.
In one embodiment, the active portion of the voltage regulator 440 is integrated in the die 430. Thus, the active portion of the voltage regulator 440 responds quickly to current transients that occur in the die 430. According to one embodiment, the active portion of the voltage regulator 440 has a response frequency of approximately 200 MHz. Additionally, embedded passive components such as the embedded inductor 450 and the embedded capacitor 460 in the packaging substrate 420 reduce area on the die 430 that would otherwise be occupied by passive components. The voltage regulator 440 with embedded passive components as described above may, according to one embodiment, provide currents of several amps to the die 430.
In an alternative configuration, some of the embedded passive components may be replaced with vias in the packaging substrates. FIG. 5 is a cross-sectional view illustrating an exemplary voltage regulator on a die with an embedded parasitic inductance according to a second embodiment.
The packaging substrate 420 includes vias 526 having a parasitic inductance used by the active portion of the voltage regulator 440 as inductors for supplying voltage to the die 430. The vias 526 may be through vias, which extend the entire height of the packaging substrate 420. The through vias 526 may be coupled through the packaging connection 422 to through vias 516 in the PCB 410 if a larger inductance is desired than obtained with the through vias 526 alone. The use of parasitic inductance in through vias within the packaging substrate as a passive component simplifies semiconductor manufacturing by reducing a number of processes to embed inductors in the packaging substrate.
According to a third embodiment, an active portion of a voltage regulator may be separated from the die and mounted on the packaging substrate. FIG. 6 is a cross-sectional view illustrating an exemplary voltage regulator on a packaging substrate according to a third embodiment. An IC product 600 includes a packaging substrate 620 coupled to a PCB 610 through a packaging connection 622 such as bumps or pillars. A die 630 is coupled to the packaging substrate 620 through an interconnect structure 632 such as bumps or pillars. Additionally, an active portion of a voltage regulator 640 is coupled to the packaging substrate 620 through an interconnect structure 642 such as bumps or pillars. Inside the packaging substrate 620 is an embedded inductor 650 and an embedded capacitor 660.
The embedded capacitor 660 is coupled to the die 630 through an electrical path 628 and to the embedded inductor 650 through an e