Electrostatic discharge (ESD) protection structure

• US 7,576,414 B2
• Filed: 11/02/2007
• Issued: 08/18/2009
• Est. Priority Date: 11/02/2007
• Status: Active Grant

• Current Assignee: Stats Chippac Pte. Lte.
• Original Assignee: Stats Chippac Limited
• Inventors: Chow, Seng Guan, Huang, Rui, Lin, Yaojian
• Primary Examiner(s): COLEMAN, WILLIAM D
• Application Number:
  US11/934,654
• Publication Number:
  US 20090117729A1
• Time in Patent Office: 655 Days
• Field of Search: 257/630, 257/E23.013, 257/E21.51, 438/121
• US Class Current: 257/630
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/10122 being formed on the semiconductor or solid-state body to be connected
• CPC Class Codes: H01L 2224/1134 Stud bumping, i.e. using a wire-bonding apparatus
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/13144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/1411 the bump connectors being bonded to at least one common bonding area
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4813 Connecting within a semiconductor or solid-state body, i.e. fly wire, bridge wire
• CPC Class Codes: H01L 2224/48599 Principal constituent of the connecting portion of the wire connector being Gold (Au)
• CPC Class Codes: H01L 23/60 Protection against electrostatic charges or discharges, e.g. Faraday shields
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/13 of an individual bump connector
• CPC Class Codes: H01L 24/16 of an individual bump connector
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01083 : Bismuth [Bi]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/30105 : Capacitance
• CPC Class Codes: H01L 2924/3011 : Impedance

Abstract

A semiconductor device has a substrate with a plurality of active devices formed thereon. A contact pad is formed on the substrate. A solder bump is formed on the contact pad. An electrostatic discharge (ESD) bump electrode is formed on the contact pad. The ESD bump electrode has a tip. The ESD bump electrode is made with gold. A chip carrier substrate has a contact pad metallurgically connected to the solder bump. The chip carrier substrate also has a ground plate. The ground plate is a low impedance ground point. The tip of the ESD bump electrode is separated from the ground plate by a distance according to ESD sensitivity of the active devices. The distance is determined by a ratio of a discharging threshold voltage for ESD sensitivity of the active device to be protected to an atmosphere discharging voltage.

Claims

1. A semiconductor device, comprising:

a substrate having a plurality of active devices formed thereon;

a contact pad formed on the substrate;

a solder bump formed on the contact pad of the substrate;

an electrostatic discharge (ESD) bump electrode having a height H formed on the contact pad of the substrate; and

a chip carrier substrate having a contact pad connected to the solder bump, the chip carrier substrate further including a ground plate, wherein the ESD bump electrode is separated from the ground plate by a distance D which is exposed to atmosphere and selected as a ratio of discharging threshold voltage for the active devices to discharging voltage of the atmosphere;

wherein the ESD bump electrode, atmosphere, and ground plate respectively constitute a metal-insulator-metal capacitor having an electric field determined by the distance D which is less than electrostatic energy induced on the contact pad for discharging the electrostatic energy to protect the active devices.

2. The semiconductor device of claim 1, wherein the ESD bump electrode includes a tip, wire loop, or a metal stick.

3. The semiconductor device of claim 1, wherein the ESD bump electrode is made with gold.

4. The semiconductor device of claim 1, wherein the ground plate is a low impedance ground point.

5. The semiconductor device of claim 1, wherein the height H of the ESD bump electrode ranges from 65 to 85 micrometers with a variation of +/−

10 micrometers.

6. The semiconductor device of claim 1, wherein the ESD bump electrode is formed with stacked bumps to create the distance D.

7. A method of making a semiconductor device, comprising:

providing a substrate having a plurality of active devices formed thereon;

forming a contact pad on the substrate;

forming a solder bump on the contact pad of the substrate;

forming an electrostatic discharge (ESD) bump electrode on the contact pad of the substrate having a height H ranging from 65 to 85 micrometers with a variation of +/−

10 micrometers, the ESD bump electrode having a tip; and

providing a chip carrier substrate having a contact pad metallurgically connected to the solder bump, the chip carrier substrate further including a ground plate, wherein the tip of the ESD bump electrode is separated from the ground plate by a distance D which is exposed to atmosphere and selected as a ratio of discharging threshold voltage for the active devices to discharging voltage of the atmosphere;

wherein the ESD bump electrode, atmosphere, and ground plate respectively constitute a metal-insulator-metal capacitor having an electric field determined by the distance D which is less than electrostatic energy induced on the contact pad for discharging the electrostatic energy to protect the active devices.

8. The method of claim 7, wherein the ESD bump electrode is made with gold.

9. The method of claim 7, wherein the ground plate is a low impedance ground point.

10. The method of claim 7, wherein the height H of the ESD bump electrode ranges from 65 to 85 micrometers with a variation of +/−

10 micrometers.

11. The method of claim 7, further including forming the ESD bump electrode with stacked bumps to create the distance D.

12. A method of making a semiconductor device, comprising:

providing a substrate having a plurality of active devices formed thereon;

forming a contact pad on the substrate;

forming a solder bump on the contact pad of the substrate;

forming an electrostatic discharge (ESD) bump electrode on the contact pad of the substrate having a height H; and

providing a chip carrier substrate having a contact pad connected to the solder bump, the chip carrier substrate further including a ground plate, wherein the ESD bump electrode is separated from the ground plate by a distance D which is exposed to atmosphere and selected as a ratio of discharging threshold voltage for the active devices to discharging voltage of the atmosphere;

wherein the ESD bump electrode, atmosphere, and ground plate respectively constitute a metal-insulator-metal capacitor having an electric field determined by the distance D which is less than electrostatic energy induced on the contact pad for discharging the electrostatic energy to protect the active devices.

13. The method of claim 12, wherein the ESD bump electrode includes a wire loop.

14. The method of claim 12, wherein the ESD bump electrode includes a metal stick.

15. The method of claim 12, wherein the ESD bump electrode is made with gold.

16. The method of claim 12, wherein the ground plate is a low impedance ground point.

17. The method of claim 12, wherein the height H of the ESD bump electrode ranges from 65 to 85 micrometers with a variation of +/−

10 micrometers.

18. The method of claim 12, further including forming the ESD bump electrode with stacked bumps to create the distance D.

19. A method of making a semiconductor device, comprising:

providing a substrate having a plurality of active devices formed thereon;

forming an interconnect site on the substrate;

forming a contact structure on the interconnect site of the substrate;

forming an electrostatic discharge (ESD) structure between the substrate and the chip carrier substrate, the ESD structure including an ESD bump electrode and ground plate; and

providing a chip carrier substrate having an interconnect site connected to the contact structure, wherein the ESD bump electrode is separated from the ground plate by a distance D which is exposed to atmosphere and selected as a ratio of discharging threshold voltage for the active devices to discharging voltage of the atmosphere;

wherein the ESD bump electrode, atmosphere, and ground plate respectively constitute a metal-insulator-metal capacitor having an electric field determined by the distance D which is less than electrostatic energy induced on the contact pad for discharging the electrostatic energy to protect the active devices.

20. The method of claim 19, wherein the ESD bump electrode includes a wire loop.

21. The method of claim 19, wherein the ESD bump electrode includes a metal stick.

22. The method of claim 19, wherein the ESD bump electrode is made with gold.

23. The method of claim 19, wherein the ESD bump electrode has a height H ranging from 65 to 85 micrometers with a variation of +/−

10 micrometers.

24. The method of claim 19, further including forming the ESD bump electrode with stacked bumps to create the distance D.