Power semiconductor module and method for producing the same

• US 7,986,034 B2
• Filed: 03/21/2008
• Issued: 07/26/2011
• Est. Priority Date: 09/21/2005
• Status: Active Grant

• Current Assignee: Infineon Technologies AG, Qimonda AG (Infineon Technologies AG)
• Original Assignee: Infineon Technologies AG
• Inventors: Strotmann, Guido, Kemper, Alfred
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US12/052,863
• Publication Number:
  US 20080211091A1
• Time in Patent Office: 1,222 Days
• Field of Search: 257/773, 257/784, 257/690, 257/E21.499, 257/E21.5, 257/E23.009, 257/E23.023, 438/106
• US Class Current: 257/690
• CPC Class Codes: B23K 20/10 making use of vibrations, e.g. ultrasonic welding
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/4807 of bonding interfaces, e.g. interlocking features
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48458 of the interface with the bonding area
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/4903 Connectors having different sizes, e.g. different diameters
• CPC Class Codes: H01L 2224/49051 Connectors having different shapes
• CPC Class Codes: H01L 2224/4911 the connectors being bonded to at least one common bonding area, e.g. daisy chain
• CPC Class Codes: H01L 2224/49111 the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85099 : Ambient temperature
• CPC Class Codes: H01L 2224/85205 : Ultrasonic bonding
• CPC Class Codes: H01L 24/29 : of an individual layer 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 24/49 : of a plurality of wire connectors
• 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 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 25/072 : the devices being arranged next to each other
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H05K 1/0306 : Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 2201/1028 : Thin metal strips as connectors or conductors
• CPC Class Codes: H05K 2201/10287 : Metal wires as connectors or conductors
• CPC Class Codes: H05K 2203/0285 : Using ultrasound, e.g. for cleaning, soldering or wet treatment
• CPC Class Codes: H05K 3/328 : by welding
• CPC Class Codes: H05K 3/4046 : using auxiliary conductive elements, e.g. metallic spheres, eyelets, pieces of wire

Abstract

A method for producing a power semiconductor module including forming a contact between a contact region and a contact element as an ultrasonic welding contact via a sonotrode. The ultrasonic welding operation also being used for joining the contact regions with the contact ends and consequently for joining the contacts and the foot regions.

Claims

1. A method for producing a power semiconductor module, the method comprising:

mechanically and electrically connecting a first contact end of a contact element of the power semiconductor module to a first contact region of a power semiconductor circuit of the power semiconductor module via ultrasonic welding, thereby forming a first contact; and

joining a further contact end of the contact element with a further contact region of the semiconductor circuit via ultrasonic welding, thereby forming a further contact electrically and mechanically connected to the first contact;

wherein the contact element is a current tap made of solid copper or substantially copper-containing alloy with a material thickness between approximately 0.1 mm and approximately 3.0 mm and a current-carrying capacity between approximately 50 A and approximately 2000 A;

wherein at least one of the contact regions is formed by a copper or substantially copper-containing layer of a direct copper bonding DCB substrate, the layer having a material thickness between approximately 0.1 mm and approximately 1.0 mm;

wherein the ultrasonic welding is performed via a sontrode with an ultrasonic welding power between approximately 300 W and 10 kW and a joining force between approximately 500 N and 3500 N.

2. The method according to claim 1, wherein the current taps have a material thickness between approximately 0.8 mm and approximately 1.5 mm.

3. The method according to claim 1, wherein the current taps have a current-carrying capacity between approximately 300 A and approximately 1000 A.

4. The method according to claim 1, wherein the DCB substrate with a copper or primarily copper-containing layer has a material thickness between approximately 0.25 mm and approximately 0.6 mm.

5. The method according to claims 1, wherein the ultrasonic welding power lies between approximately 500 W and approximately 2 kW.

6. The method according to claim 1, wherein the frequency for the ultrasonic welding lies between approximately 20 kHz and approximately 35 kHz.

7. The method according to claim 1, wherein the energy for the ultrasonic welding lies between approximately 50 Ws and approximately 3 kWs.

8. The method according to claim 1, wherein the amplitude for the ultrasonic welding lies between approximately 15 μ

m and approximately 50 μ

m.

9. The method according to claim 1, wherein the welding time for the ultrasonic welding is between approximately 50 ms and approximately 2000 ms.

10. The method according to claim 1, wherein the first contact ends of the contact elements are formed with energy direction indicators in the form of elevations at the first contact ends for better force alignment during ultrasonic welding.

11. The method according to claim 10, wherein the energy direction indicators have a material thickness between approximately 0.05 mm and approximately 0.50 mm.

12. The method according to claim 10, wherein the energy direction indicators have a diameter between approximately 0.5 mm and approximately 4.0 mm.

13. The method according to claim 10, wherein the energy direction indicators have an area between approximately 0.2 mm² and approximately 12.5 mm².

14. The method according to claim 10, further comprising:

performing a calibration operation including exerting pressure simultaneously on a plurality of contact ends via the sonotrode until all the energy direction indicators are mechanically contact-connected.

15. The method according to claim 1, wherein the ultrasonic welding is performed as a simultaneous multiple welding operation including simultaneously contact-connecting a plurality of contact elements via a plurality of contact ends with a respective current-carrying capacity between approximately 50 A and approximately 500 A.

16. The method according to claim 1, wherein the ultrasonic welding operation includes lowering the sonotrode onto the contact region such that the respective contact end is thereby pressed under force or pressure on to the surface of the respective contact region.

17. The method according to claim 1, wherein joining the contact end of the contact element includes:

holding and positioning a respective contact element via a holding and positioning device.

18. The method according to claim 1, wherein a respective contact end of the contact element is contact-connected at one location or at one point as an individual foot region configured to transmit current and/or potential.

19. The method according to claim 1, wherein a respective contact end of the contact element is contact-connected at a plurality of locations or at a plurality of points as a plurality of foot regions configured to transmit current and/or potential.

20. The method according to claim 1, wherein the contact element is an element selected from the group consisting of:

contact wires, bonding wires, litz wires and stamped parts.

21. The method according to claim 1, wherein the contact element comprises at least one material selected from the group consisting of:

copper and aluminum.

22. The method according to claim 1, wherein the contact end and/or the contact are formed in meandering fashion.

23. The method according to claim 1, wherein the contact region is a pad.

24. The method according to claim 1, wherein the ultrasonic welding operation includes:

using, in the vicinity of edge regions of the contact regions, a welding direction and/or vibration direction which runs substantially parallel to the direction of the respective edge region in order to avoid detachment of the contact region at the DCB substrate.

25. A power semiconductor module, comprising:

a power semiconductor circuit with contact regions;

a contact element with contact ends mechanically and electrically connected to respective ones of the contact regions via ultrasonically welded contacts; and

a direct copper bonding DCB substrate including a copper or substantially copper-containing layer having a material thickness between approximately 0.1 mm and approximately 1.0 mm;

wherein the contact element is a current tap made of solid copper or substantially copper-containing alloy with a material thickness between approximately 0.1 mm and approximately 3.0 mm and a current-carrying capacity between approximately 50 A and approximately 2000 A;

wherein at least one of the contact regions is part of the copper or substantially copper-containing layer.

26. The power semiconductor module according to claim 25, wherein at least one contact element is a current tap with at least two contact ends contact-connected via contacts with contact regions being foot points.

27. The power semiconductor module according to claim 25, wherein, in the vicinity of edge regions of the contact regions of the DCB substrate, the formed contacts are at a minimum distance from the edge regions which approximately corresponds to the thickness of the contact end contact-connected with the respective contact, the distance being between approximately 0.5 mm and approximately 1.5 mm.

28. The power semiconductor module according to claim 25, wherein, in the vicinity of edge regions of the contact regions of the DCB substrate, the welded area of a contact is at a minimum distance from the edge regions which approximately corresponds to the thickness of the contact ends contact-connected with the respective contact, the distance being between approximately 0.5 mm and approximately 1.5 mm.

29. The power semiconductor module according to claim 25, wherein the welded area of a contact corresponds approximately to one to three times the cross-sectional area of the respective contact element in the region of the respective contact end.