Power Module and Power Conversion Device Using Power Module

• US 20130265724A1
• Filed: 06/29/2011
• Published: 10/10/2013
• 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
• Granted Patent: US 9,277,682 B2
• Time in Patent Office: Days
• US Class Current: 361/715
• 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 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, and 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, and S₃ denotes the size of a lead frame bared part of the power unit, 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 heat sink is 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 metal joining material between them, a second lead frame coupled to the other electrode surface of the semiconductor device with the metal joining material between them, and a sealing material with which the semiconductor device, first lead frame, and 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 the internal wall of the case; and

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

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

the second lead frame is bared out of the sealing material, and the 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 the perimeter of the opening of the case;

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

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

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

h₁−

h₂−

h₃ is established.

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

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

the second lead frame has a convex part formed on a part thereof opposed to the other electrode surface of the semiconductor device, the semiconductor device is disposed on the convex part; and

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

7. The power module according to any of claim 3, wherein:

the sealed body has a projection thereof, into which the sealed body is projected in a direction perpendicular to the bared surface of the first lead frame, shaped substantially like a square, and has projections formed to jut out from two adjoining sides of the substantial square; and

the case has concave parts, into which the projections are fitted, formed in the internal surface of the case.

8. (canceled)