Metal-on-passivation resistor for current sensing in a chip-scale package
View Patent ↗A current sense resistor integrated with an integrated circuit die housed in a chip-scale semiconductor package includes a metal layer formed over a passivation layer of the integrated circuit die where the metal layer having an array of metal pillars extending therefrom. The metal pillars are to be electrically connected to a first conductive electrode and a second conductive electrode external to the chip-scale semiconductor package where the first conductive electrode and the second conductive electrode are physically separated from each other by a separation of a first distance. The current sense resistor is formed in a portion of the metal layer spanning the separation between the first and second conductive electrodes. In some embodiments, a semiconductor device including an integrated circuit die housed in a chip-scale semiconductor package includes a current sense resistor formed in a metal layer formed over a passivation layer of the integrated circuit die.
1. A current sense resistor integrated with an integrated circuit die, the integrated circuit die being housed in a chip-scale semiconductor package, the current sense resistor comprising:
a metal layer formed over a passivation layer of the integrated circuit die, the metal layer having an array of metal pillars extending therefrom, the metal pillars to be electrically connected to a first conductive electrode and a second conductive electrode external to the chip-scale semiconductor package where the first conductive electrode and the second conductive electrode are physically separated from each other by a separation of a first distance,
wherein the current sense resistor is formed in a portion of the metal layer spanning the separation between the first and second conductive electrodes.
2. The current sense resistor of claim 1 , wherein the metal layer comprises a blanket metal layer and metal pillars extending from the blanket metal layer, each metal pillar being capped by a solder bump.
3. The current sense resistor of claim 1 , wherein the first conductive electrode comprises a first conductive trace portion formed on a printed circuit board and the second conductive electrode comprises a second conductive trace portion formed on the printed circuit board, the first conductive trace portion and the second conductive trace portion being physically separated from each other by the separation of the first distance on the printed circuit board.
4. The current sense resistor of claim 1 , wherein the metal layer includes a first metal pillar formed closest to the separation and to be electrically connected to the first conductive electrode and a second metal pillar formed closest to the separation and to be electrically connected to the second conductive electrode, the current sense resistor having a resistance value determined by the distance between the first metal pillar and the second metal pillar.
5. The current sense resistor of claim 4 , wherein the positioning of the first and second metal pillars relative to the separation is varied to vary the resistance value of the current sense resistor.
6. The current sense resistor of claim 1 , wherein the separation has a distance d between the first conductive electrode and the second conductive electrode and a length L, and the portion of the metal layer forming the current sense resistor has a length equal to or less than the length L.
7. The semiconductor device of claim 1 , wherein the metal layer comprises one of copper or a metal alloy.
8. A semiconductor device including an integrated circuit die housed in a chip-scale semiconductor package, the semiconductor device comprising:
a current sense resistor formed in a metal layer formed over a passivation layer of the integrated circuit die, the metal layer comprising a blanket metal layer and an array of metal pillars extending from the blanket metal layer,
wherein the metal pillars are to be electrically connected to a first conductive electrode and a second conductive electrode external to the chip-scale semiconductor package where the first conductive electrode and the second conductive electrode are physically separated from each other by a separation of a first distance, the current sense resistor being formed in a portion of the metal layer spanning the separation between the first and second conductive electrodes.
9. The semiconductor device of claim 8 , wherein the first conductive electrode comprises a first conductive trace portion formed on a printed circuit board and the second conductive electrode comprises a second conductive trace portion formed on the printed circuit board, the first conductive trace portion and the second conductive trace portion being physically separated from each other by the separation of the first distance on the printed circuit board.
10. The semiconductor device of claim 8 , wherein the metal layer includes a first metal pillar formed closest to the separation and to be electrically connected to the first conductive electrode and a second metal pillar formed closest to the separation and to be electrically connected to the second conductive electrode, the current sense resistor having a resistance value determined by the distance between the first metal pillar and the second metal pillar.
11. The semiconductor device of claim 10 , wherein the positioning of the first and second metal pillars relative to the separation is varied to vary the resistance value of the current sense resistor.
12. The semiconductor device of claim 11 , wherein the first and second metal pillars are positioned in close proximity to the separation to form a current sense resistor having a small resistance value.
13. The semiconductor device of claim 11 , wherein the first and second metal pillars are positioned away from the separation to form a current sense resistor having a large resistance value.
14. The semiconductor device of claim 8 , wherein the separation has a distance d between the first conductive electrode and the second conductive electrode and a length L.
15. The semiconductor device of claim 8 , wherein the portion of the metal layer forming the current sense resistor has a length equal to or less than the length L.
16. The semiconductor device of claim 8 , wherein the metal layer comprises copper.
17. The semiconductor device of claim 8 , wherein the metal layer comprises a metal alloy.
18. The semiconductor device of claim 8 , further comprising a first contact electrode and a second contact electrode formed in the passivation layer of the integrated circuit die and electrically connected to the metal layer, the first and second contact electrodes being configured to measure a temperature of the current sense resistor.
19. The semiconductor device of claim 8 , wherein the integrated circuit die comprises a current monitor integrated circuit die and wherein the first conductive electrode is electrically connected to a first current sense terminal and the second conductive electrode is electrically connected to a second current sense terminal of the current monitor integrated circuit die.