HIGH Q TRANSFORMER DISPOSED AT LEAST PARTLY IN A NON-SEMICONDUCTOR SUBSTRATE

• US 20100026368A1
• Filed: 08/01/2008
• Published: 02/04/2010
• Est. Priority Date: 08/01/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tang, Yiwu, Jin, Zhang
• Granted Patent: US 8,237,269 B2
• Time in Patent Office: Days
• US Class Current: 327/361
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/49534 Multi-layer
• CPC Class Codes: H01L 23/50 for integrated circuit devices, e.g. power bus, number of leadsH01L23/482 - H01L23/498 take precedence
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

An assembly involves an integrated circuit die that is bonded, e.g., flip-chip bonded, to a non-semiconductor substrate by a plurality of low-resistance microbumps. In one novel aspect, at least a part of a novel high-frequency transformer is disposed in the non-semiconductor substrate where the non-semiconductor substrate is the substrate of a ball grid array (BGA) integrated circuit package. At least one of the low-resistance microbumps connects the part of the transformer in the substrate to a circuit in the integrated circuit die. At two gigahertz, the novel transformer has a coupling coefficient k of at least at least 0.4 and also has a transformer quality factor Q of at least ten. The novel transformer structure sees use in coupling differential outputs of a mixer to a single-ended input of a driver amplifier in a transmit chain of an RF transceiver within a cellular telephone.

Claims

1. A structure comprising:

a non-semiconductor substrate that includes a portion of a transformer; and

an integrated circuit die that is bonded to the non-semiconductor substrate by a plurality of microbumps, wherein the portion of the transformer in the non-semiconductor substrate is connected to at least one of the microbumps.

2. The structure of claim 1, wherein the transformer has a coupling coefficient k at two gigahertz of at least 0.4, and wherein the transformer has a transformer quality factor Q at two gigahertz of at least ten.

3. The structure of claim 1, wherein the transformer includes a primary and a secondary, a first portion of the primary being disposed in the integrated circuit die, a second portion of the primary being disposed in the non-semiconductor substrate, and wherein the first portion of the primary is connected to the second portion of the primary by said one of the microbumps.

4. The structure of claim 1, wherein the transformer includes a primary and a secondary, a first portion of the secondary being disposed in the integrated circuit die, a second portion of the secondary being disposed in the non-semiconductor substrate, and wherein the first portion of the secondary is connected to the second portion of the secondary by said one of the microbumps.

5. The structure of claim 2, wherein the transformer includes a primary and a secondary, a first portion of the primary being disposed in the integrated circuit die, a second portion of the primary being disposed in the non-semiconductor substrate, the first portion of the primary being connected to a first end of the second portion of the primary by said one of the microbumps, a second end of the second portion of the primary being connected to a second of the microbumps, wherein a first portion of the secondary is disposed in the integrated circuit die, a second portion of the secondary being disposed in the non-semiconductor substrate, and wherein the first portion of the secondary is connected to the second portion of the secondary by a third of the microbumps.

6. The structure of claim 5, wherein the transformer has a self-resonant frequency greater than 4.0 gigahertz.

7. The structure of claim 5, wherein the integrated circuit die includes a mixer, the mixer having a first output node and a second output node, the first output node being connected to an end of the first portion of the primary, and wherein the second output node is connected to the second microbump.

8. The structure of claim 1, wherein the transformer includes a primary and a secondary, the primary being disposed substantially entirely in the integrated circuit die, the secondary being disposed substantially entirely in the non-semiconductor substrate, and wherein the secondary is connected by said one of the microbumps to the integrated circuit die.

9. The structure of claim 2, wherein the transformer includes a primary and a secondary, the primary being disposed substantially entirely in the integrated circuit die, the secondary being disposed substantially entirely in the non-semiconductor substrate, wherein a first end of the secondary is connected by said one of the microbumps to the integrated circuit die, wherein the non-semiconductor substrate includes a ground node, and wherein a second end of the secondary is connected to the ground node.

10. The structure of claim 9, wherein the secondary includes at least one turn of a conductor, and wherein the secondary includes no cross-overs.

11. The structure of claim 9, wherein the primary is connected to no microbump, wherein the integrated circuit die includes a mixer having a first output node and a second output node, the first output node being connected to a first end of the primary, the second output node being connected to a second end of the primary.

12. The structure of claim 2, wherein the transformer includes a primary and a secondary, wherein both the primary and secondary are disposed substantially entirely in the non-semiconductor substrate, wherein said one of the microbumps is connected to a first end of the primary, a second of the microbumps being connected to a second end of the primary, and a third of the microbumps being connected to the secondary.

13. The structure of claim 12, wherein the secondary includes at least one turn of a conductor, and wherein the secondary includes no cross-overs.

14. A method comprising:

connecting circuitry in an integrated circuit die via a first microbump to at least a portion of a transformer in a non-semiconductor substrate.

15. The method of claim 14, wherein said connecting involves flip-chip mounting the integrated circuit die to the non-semiconductor substrate by a plurality of microbumps, the first microbump being one of the plurality of microbumps.

16. The method of claim 15, wherein the transformer has a coupling coefficient k at two gigahertz of at least 0.4, and wherein the transformer has a transformer quality factor Q at two gigahertz of at least ten.

17. The method of claim 16, further comprising:

connecting the circuitry in the integrated circuit die via a second microbump of the plurality of microbumps to the portion of the transformer in the non-semiconductor substrate.

18. The method of claim 17, wherein the transformer includes a primary and a secondary, and wherein the portion is the secondary.

19. The method of claim 17, wherein the transformer includes a primary and a secondary, and wherein the portion is a portion of the secondary.

20. The method of claim 17, wherein the transformer includes a primary and a secondary, and wherein the portion is the primary.

21. The method of claim 17, wherein the transformer includes a primary and a secondary, and wherein the portion is a portion of the primary.

22. A method comprising:

providing a microbump that is directly connected to one of an output node of a mixer and an input node of a driver amplifier, wherein the mixer and the driver amplifier are parts of an integrated circuit die, and wherein the microbump is a part of the integrated circuit die.

23. The method of claim 22, further comprising:

providing a programmable variable capacitor that is connected to said one of the output node of the mixer and the input node of the driver amplifier.

24. The method of claim 22, wherein the microbump is directly connected to at least one complete turn of a conductor.

25. An integrated circuit die comprising:

a mixer having a first output node and a second output node;

a driver amplifier having an input node; and

a first microbump that is connected via a conductor to one of the first output node of the mixer, the second output node of the mixer and the input node of the driver amplifier.

26. The integrated circuit die of claim 25, wherein the conductor is at least a part of a primary of a transformer, the transformer including a secondary, wherein the secondary is connected to the input node of the driver amplifier.

27. The integrated circuit die of claim 25, wherein the conductor is at least a part of a secondary of a transformer, the transformer including a primary, wherein the primary is connected to first output node of the mixer.

28. A packaged integrated circuit, comprising:

an integrated circuit die that includes a circuit and a microbump; and

means that is connected to the integrated circuit die by the microbump, wherein the means is for providing at least a part of a transformer such that the part of the transformer is connected to the circuit through the microbump, such that the transformer has a coupling coefficient k at two gigahertz of at least 0.4, such that the transformer has a quality factor Q at two gigahertz of at least ten, and such that the transformer has a self-resonant frequency greater than 4.0 gigahertz.

29. The packaged integrated circuit of claim 28, wherein the circuit includes a mixer and a driver amplifier, wherein the mixer drives the driver amplifier through the transformer.

30. The packaged integrated circuit of claim 28, wherein the means is a non-semiconductor substrate of a ball grid array (BGA) package.