Power module and power conversion device using power module

• US 9,277,682 B2
• Filed: 06/29/2011
• Issued: 03/01/2016
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Kaneko, Yujiro, Suwa, Tokihito
• Primary Examiner(s): HOFFBERG, ROBERT JOSEPH
• Application Number:
  US13/807,277
• Publication Number:
  US 20130265724A1
• Time in Patent Office: 1,707 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 2224/0603 Bonding areas having different sizes, e.g. different heights or widths
• CPC Class Codes: H01L 2224/33 of a plurality of layer connectors
• CPC Class Codes: H01L 2224/37099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2224/73221 Strap and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 2224/8384 Sintering
• CPC Class Codes: H01L 2224/84801 Soldering or alloying
• CPC Class Codes: H01L 2224/8484 Sintering
• CPC Class Codes: H01L 23/36 Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks H01L23/28, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence; heating H01L23/345
• CPC Class Codes: H01L 23/4334 Auxiliary members in encapsulations H01L23/49568 takes precedence
• CPC Class Codes: H01L 23/473 by flowing liquids H01L23/4332, H01L23/4338 take precedence
• CPC Class Codes: H01L 24/33 of a plurality of layer connectors
• CPC Class Codes: H01L 24/34 Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
• CPC Class Codes: H01L 25/07 the devices being of a type provided for in group H01L29/00
• CPC Class Codes: H01L 25/072 the devices being arranged next to each other
• CPC Class Codes: H01L 25/18 : the devices being of types provided for in two or more different subgroups of the same main group of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N
• 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 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 : Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H05K 7/209 : Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20909 takes precedence

Abstract

A power module includes a power unit equipped with plural power semiconductor devices, heat sinks, and a housing case. The power unit includes the power semiconductor devices, lead frames, and a sealing resin. The lead frames are coupled to the surfaces of each of the power semiconductor devices, and parts of the external surfaces of the upper and lower lead frames are bared out of the sealing resin. The housing case includes a housing base and a housing cover. The housing base, heat sink, power unit, heat sink, and housing cover are layered in that order. Assuming that S₁ denotes the outline size of the housing base, S₂ denotes the outline size of the housing cover, S₃ denotes the size of the lead frame bared part of the power unit, the relationship of S₁>S₂>S₃ is established. The housing cover is pressed and fixed to a receiving part of the housing base.

Claims

1. A power module, comprising:

a power unit equipped with a plurality of power semiconductor devices;

heat sinks; and

a housing case, wherein

the power unit includes the power semiconductor devices, lead frames, and a sealing resin;

the lead frames are coupled to surfaces of each of the power semiconductor devices, and parts of external surfaces of an upper lead frame of the lead frames and a lower lead frame of the lead frames are bared out of the sealing resin;

the housing case includes a housing base and a housing cover, and the housing base, a first heat sink of the heat sinks, the power unit, a second heat sink of the heat sinks, and the housing cover are layered in that order;

assuming that S1 denotes an outline size of the housing base, S2 denotes an outline size of the housing cover, and S3 denotes a size of a lead frame bared part of the power unit, the lead frame bared part being formed on each of the upper lead frame and the lower lead frame, the relationship of S1>

S2>

S3 is established; and

the housing cover is pressed and fixed to a receiving part of the housing base.

2. The power module according to claim 1, wherein the first heat sink and the second heat sink are softer than the sealing resin.

3. A power module, comprising:

a sealed body including a semiconductor device, a first lead frame coupled to one of electrode surfaces of the semiconductor device with a first metal joining material between the first lead frame and the one of the electrode surfaces, a second lead frame coupled to another of the electrode surfaces of the semiconductor device with a second metal joining material between the second lead frame and the another of the electrode surfaces, and a sealing material with which the semiconductor device, the first lead frame, and the second lead frame are sealed;

a case that accommodates the sealed body and has an opening formed therein;

a cover shaped to be larger than an opening area of the opening of the case;

a first insulating member disposed between the sealed body and an internal wall of the case; and

a second insulating member disposed between the sealed body and the cover, wherein

the first lead frame has a first barded surface that is bared out of the sealing material, and the first bared surface of the first lead frame is brought into contact with the first insulating member;

the second lead frame has a second bared surface that is bared out of the sealing material, and the second bared surface of the second lead frame is brought into contact with the second insulating member;

the case has a cover receiving part formed on a perimeter of the opening of the case;

the cover has a part thereof, which is opposed to the second insulating member, formed as a cover projection that juts out toward the sealed body, and the cover is fixed to the cover receiving part;

at least one of the first insulating member or the second insulating member is formed so that a thickness thereof varies depending on a predetermined pressing force, and the at least one of the first insulating member or the second insulating member is pressed against the sealed body with the thickness thereof varied with the predetermined pressing force from the cover projection of the cover.

4. The power module according to claim 3, wherein assuming that h₁ denotes a height from the internal wall of the case to a surface of the cover receiving part opposed to the cover, h₂ denotes a height of the cover projection, h₃ denotes a height from the first bared surface of the first lead frame to the second bared surface of the second lead frame, and T denotes a sum of a thickness of the first insulating member and a thickness of the second insulating member, before application of the predetermined pressing force, the relationship of T>

h₁−

h₂−

h₃ is established.

5. The power module according to claim 3, wherein a compressibility of at least one of the first insulating member or the second insulating member is equal to or larger than 10% and equal to or smaller than 60% in relation to an uncompressed thickness of the at least one of the first insulating member or the second insulating member.

6. The power module according to claim 3, wherein:

the second lead frame has a convex part formed on a part thereof opposed to the another of the electrode surfaces of the semiconductor device;

the semiconductor device is disposed on the convex part; and

the second bared surface of the second lead fame is formed to be larger than an area of the convex part.