Hermetically sealed semiconductor power module and large scale module comprising the same

• US 6,756,667 B2
• Filed: 07/31/2001
• Issued: 06/29/2004
• Est. Priority Date: 05/15/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Hiyoshi, Michiaki
• Primary Examiner(s): Lee, Eddie
• Assistant Examiner(s): Owens, Douglas W.
• Application Number:
  US09/917,876
• Publication Number:
  US 20020027283A1
• Time in Patent Office: 1,064 Days
• Field of Search: 257/584, 257/703-707, 257/723, 257/732, 257/731, 257/691, 257/729, 361/74, 361/100, 361/321, 361/386, 361/401, 361/717, 361/736
• US Class Current: 257/703
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48095 Kinked
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 2224/49111 the connectors connecting two common bonding areas, e.g. Litz or braid wires
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/1301 Thyristor
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

This is a semiconductor power module provided with: a ceramic substrate; a metallic plate bonded to a surface of this substrate; a cylindrical metallic flange which is hermetically bonded to a surface of substrate or the metallic plate; a ceramic housing for hermetically sealing an opening of the metallic flange; and at least one or more semiconductor chips soldered to the metallic plate. The metallic flange is made of metal with a low thermal expansion coefficient. A hermetically sealed container is created by welding the metallic flange, the ceramic substrate and the housing with silver brazing. Moreover, external collector, emitter and gate electrodes are bonded on the housing by using the silver brazing. The collector, emitter and gate conductive pillars are respectively connected to the external collector, emitter and gate electrodes with calking. Thus, this hermetically sealed container is strong in mechanical strength and high in explosion-proof durability and excellent in moisture resistance. And this semiconductor power module has a high TFT reliability and a high TCT reliability. Moreover, a power cycle durability is larger since the emitter pedals are pressure-contacted to the emitter electrode pads disposed on the semiconductor chip via the metallic hemispheres so as to implement a large conductive capacity.

Claims

1. A semiconductor power module eliminating use of bonding wires, comprising:

(a) a uniform and circular ceramic substrate;

(b) a circular metallic plate bonded to a surface of said substrate;

(c) a cylindrical metallic flange serving as an electrode, a lower end of the metallic flange is hermetically bonded to a surface of said metallic plate at a boundary of said metallic plate;

(d) a disk-shaped ceramic housing for disposing a second electrode and for hermetically sealing an opening of said metallic flange; and

(e) at least one or more semiconductor chips mounted on and soldered to said metallic plate.

2. The semiconductor power module of claim 1, further comprising an annular metallic member disposed above the semiconductor chip, and bonded to an outer circumference of said ceramic housing, wherein an end of said metallic member is bonded to an upper end of said metallic flange with a welding.

3. The semiconductor power module of claim 1, wherein a bottom surface of said semiconductor chip and said metallic flange are electrically connected to each other through said metallic plate.

4. The semiconductor power module of claim 1, wherein an electrode path associated with said second electrode is formed by pressure-contacting a conductive electrode pedal to an electrode pad disposed on said semiconductor chip.

5. The semiconductor power module of claim 4, wherein in said ceramic housing, said conductive electrode pedal is pressure-contacted to said semiconductor chip through a pressure applied to a spring.

6. The semiconductor power module of claim 1, wherein said metallic flange is a metal having a small thermal expansion coefficient.

7. The semiconductor power module of claim 1, wherein said semiconductor chip is an IGBT.

8. The semiconductor power module of claim 4, further comprising:

a conductive pillar electrically connected to said conductive electrode pedal; and

a cap-shaped external electrode aligned to a through hole penetrating said ceramic housing, uprightly bonded on said ceramic housing configured such that said conductive pillar is tightly connected to said cap-shaped external electrode with calking.

9. The semiconductor power module of claim 8, wherein said conductive electrode pedal is attached to a backbone having said conductive pillar.

10. The semiconductor power module of claim 4, further comprising a plurality of metallic hemispheres sandwiched between said conductive electrode pedal and said semiconductor chip.