lectrical path 627. The embedded inductor 650 is coupled to the active portion of the voltage regulator 640 by an electrical path 626. Voltage is provided to the active portion of the voltage regulator 640 by an electrical path 624 from the PCB 610 through the packaging connection 622, the electrical path 624, and the interconnect structure 642.
The voltage regulator of FIG. 6 is an off-die voltage regulator coupled to the same packaging substrate as the die to which the voltage regulator supplies voltage. Locating the active portion of the voltage regulator on the packaging substrate but separate from the die allows different processes to be used for manufacturing the active portion of the voltage regulator and the die. For example, the die may be fabricated with 32 nm or 45 nm processes while the active portion of the voltage regulator may be fabricated with 0.18 m processes. Additionally, the active portion of the voltage regulator may be manufactured at a different fabrication site than the die.
Turning now to a fourth embodiment, some of the embedded passive components may be replaced with vias in the packaging substrates. FIG. 7A is a cross-sectional view illustrating an exemplary voltage regulator on a packaging substrate with a parasitic inductance according to a fourth embodiment. An IC product 700 includes vias 726 in the packaging substrate 620 having a parasitic inductance that act as a filter for voltage provided from the active portion of the voltage regulator 640. Additional vias 716 in the PCB 610 may couple to the vias 726 through the packaging connection 622, if additional inductance is desired. The vias 716 are coupled through a conducting layer 730 on the PCB 610. The vias 716 or the vias 726 may be through vias, which extend the entire height of the PCB 610 or the packaging substrate 620, respectively.
Voltage is provided to the active portion of the voltage regulator 640, for example, through the electrical path 624. Regulated voltage is then output to the vias 726 and the vias 716. An electrical path 727 couples one of the vias 726 to the embedded capacitor 660, which is coupled to the die 630 through the electrical path 628.
According to a fifth embodiment, inductance is provided by wirebonds. FIG. 7B is a cross-sectional view illustrating an exemplary voltage regulator with a wirebond inductance. A wirebond 750 couples the active portion of the voltage regulator 640 to one of the vias 716. The wirebond 750, the vias 716 and the conducting layer 730 provide inductance to the active portion of the voltage regulator 640.
Embedded passives in which through vias provide inductance for a voltage regulator will now be described in further detail. FIGS. 8A-C are block diagrams illustrating paths through a packaging substrate and PCB that may provide inductance. FIG. 8A is a block diagram illustrating a path 800 through a packaging substrate and PCB according to one embodiment. A top conductive layer 802 and a bottom conductive layer 810 of a packaging substrate are shown. Inner layers 804, 806 of the packaging substrate are also shown. A through via 805, couples the top conductive layer 802 and the bottom conductive layer 810. A packaging connection 812 may be a bump of a ball grid array and couples the bottom conductive layer 810 to a top conductive layer 820 of a PCB. A through via 822 couples the top conductive layer 820 to a bottom conductive layer 830. The bottom conductive layer 830 may be an interconnect that couples to another through via in the PCB. The amount of inductance in the path 800 is proportional to a length of the path 800.
FIG. 8B is a block diagram illustrating a path 840 having a longer length than the path 800. A bottom conductive layer 842 couples the through via 822 to another through via in the PCB. The bottom conductive layer 842 includes extra length, for example in a coil, which increases the inductance of the path 840.
FIG. 8C is a block diagram illustrating a path 850 having a longer length than the path 830. An inductor coil 852 mounted on a back side of the PCB couples th