JP4976688B2 - Joining method between heat spreader and metal plate - Google Patents

Joining method between heat spreader and metal plate Download PDF

Info

Publication number
JP4976688B2
JP4976688B2 JP2005361624A JP2005361624A JP4976688B2 JP 4976688 B2 JP4976688 B2 JP 4976688B2 JP 2005361624 A JP2005361624 A JP 2005361624A JP 2005361624 A JP2005361624 A JP 2005361624A JP 4976688 B2 JP4976688 B2 JP 4976688B2
Authority
JP
Japan
Prior art keywords
copper
heat spreader
metal plate
laser
joining
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2005361624A
Other languages
Japanese (ja)
Other versions
JP2007165690A (en
Inventor
克彦 吉原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fuji Electric Co Ltd
Original Assignee
Fuji Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fuji Electric Co Ltd filed Critical Fuji Electric Co Ltd
Priority to JP2005361624A priority Critical patent/JP4976688B2/en
Publication of JP2007165690A publication Critical patent/JP2007165690A/en
Application granted granted Critical
Publication of JP4976688B2 publication Critical patent/JP4976688B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/73Means 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
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L24/36Structure, shape, material or disposition of the strap connectors prior to the connecting process
    • H01L24/37Structure, shape, material or disposition of the strap connectors prior to the connecting process of an individual strap connector
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321Disposition
    • H01L2224/32151Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32225Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/36Structure, shape, material or disposition of the strap connectors prior to the connecting process
    • H01L2224/37Structure, shape, material or disposition of the strap connectors prior to the connecting process of an individual strap connector
    • H01L2224/37001Core members of the connector
    • H01L2224/37099Material
    • H01L2224/371Material 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
    • H01L2224/37117Material 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 the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
    • H01L2224/37124Aluminium [Al] as principal constituent
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/36Structure, shape, material or disposition of the strap connectors prior to the connecting process
    • H01L2224/37Structure, shape, material or disposition of the strap connectors prior to the connecting process of an individual strap connector
    • H01L2224/37001Core members of the connector
    • H01L2224/37099Material
    • H01L2224/371Material 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
    • H01L2224/37138Material 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 the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/37147Copper [Cu] as principal constituent
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/36Structure, shape, material or disposition of the strap connectors prior to the connecting process
    • H01L2224/37Structure, shape, material or disposition of the strap connectors prior to the connecting process of an individual strap connector
    • H01L2224/3754Coating
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/36Structure, shape, material or disposition of the strap connectors prior to the connecting process
    • H01L2224/37Structure, shape, material or disposition of the strap connectors prior to the connecting process of an individual strap connector
    • H01L2224/3754Coating
    • H01L2224/37599Material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/39Structure, shape, material or disposition of the strap connectors after the connecting process
    • H01L2224/40Structure, shape, material or disposition of the strap connectors after the connecting process of an individual strap connector
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/39Structure, shape, material or disposition of the strap connectors after the connecting process
    • H01L2224/40Structure, shape, material or disposition of the strap connectors after the connecting process of an individual strap connector
    • H01L2224/4005Shape
    • H01L2224/4009Loop shape
    • H01L2224/40095Kinked
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/34Strap connectors, e.g. copper straps for grounding power devices; Manufacturing methods related thereto
    • H01L2224/39Structure, shape, material or disposition of the strap connectors after the connecting process
    • H01L2224/40Structure, shape, material or disposition of the strap connectors after the connecting process of an individual strap connector
    • H01L2224/401Disposition
    • H01L2224/40151Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/40221Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/40225Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/44Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/44Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001Core members of the connector
    • H01L2224/4501Shape
    • H01L2224/45012Cross-sectional shape
    • H01L2224/45015Cross-sectional shape being circular
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/44Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001Core members of the connector
    • H01L2224/45099Material
    • H01L2224/451Material 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
    • H01L2224/45117Material 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 the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
    • H01L2224/45124Aluminium (Al) as principal constituent
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805Shape
    • H01L2224/4809Loop shape
    • H01L2224/48091Arched
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/484Connecting portions
    • H01L2224/48475Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball
    • H01L2224/48476Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball between the wire connector and the bonding area
    • H01L2224/48491Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball between the wire connector and the bonding area being an additional member attached to the bonding area through an adhesive or solder, e.g. buffer pad
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/49Structure, shape, material or disposition of the wire connectors after the connecting process of a plurality of wire connectors
    • H01L2224/491Disposition
    • H01L2224/4911Disposition the connectors being bonded to at least one common bonding area, e.g. daisy chain
    • H01L2224/49111Disposition the connectors being bonded to at least one common bonding area, e.g. daisy chain the connectors connecting two common bonding areas, e.g. Litz or braid wires
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732Location after the connecting process
    • H01L2224/73201Location after the connecting process on the same surface
    • H01L2224/73219Layer and TAB connectors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732Location after the connecting process
    • H01L2224/73201Location after the connecting process on the same surface
    • H01L2224/73221Strap and wire connectors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732Location after the connecting process
    • H01L2224/73251Location after the connecting process on different surfaces
    • H01L2224/73265Layer and wire connectors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/83Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector
    • H01L2224/838Bonding techniques
    • H01L2224/83801Soldering or alloying
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/84Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a strap connector
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/84Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a strap connector
    • H01L2224/842Applying energy for connecting
    • H01L2224/8421Applying energy for connecting with energy being in the form of electromagnetic radiation
    • H01L2224/84214Applying energy for connecting with energy being in the form of electromagnetic radiation using a laser
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/84Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a strap connector
    • H01L2224/848Bonding techniques
    • H01L2224/84801Soldering or alloying
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001Technical content checked by a classifier
    • H01L2924/00011Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01005Boron [B]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01006Carbon [C]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01013Aluminum [Al]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01014Silicon [Si]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01028Nickel [Ni]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01029Copper [Cu]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01033Arsenic [As]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01042Molybdenum [Mo]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01074Tungsten [W]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01078Platinum [Pt]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01Chemical elements
    • H01L2924/01082Lead [Pb]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/013Alloys
    • H01L2924/014Solder alloys
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10Details of semiconductor or other solid state devices to be connected
    • H01L2924/11Device type
    • H01L2924/13Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304Transistor
    • H01L2924/1305Bipolar Junction Transistor [BJT]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10Details of semiconductor or other solid state devices to be connected
    • H01L2924/11Device type
    • H01L2924/13Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304Transistor
    • H01L2924/1305Bipolar Junction Transistor [BJT]
    • H01L2924/13055Insulated gate bipolar transistor [IGBT]
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10Details of semiconductor or other solid state devices to be connected
    • H01L2924/11Device type
    • H01L2924/13Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304Transistor
    • H01L2924/1306Field-effect transistor [FET]
    • H01L2924/13091Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Laser Beam Processing (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Description

この発明は、放熱のために半導体チップ上に固着されるヒートスプレッダと外部導出導体である金属板を固着するときのヒートスプレッダと金属板との接合方法に関する。   The present invention relates to a method of joining a heat spreader and a metal plate when fixing a heat spreader fixed on a semiconductor chip for heat dissipation and a metal plate as an external lead-out conductor.

近年、電力変換装置の小型化・高密度化が進んできている。電力変換装置の小型化・高密度化にしては、パッケージ内部の配線,パッケージ構造,放熱方法などを改良する必要がある。特にパワーデバイスであるIGBT(Insulated Gate Bipolar Transistor)、FWD(Free Wheeling Diode)、パワーMOSFETおよびパワーバイポーラトランジスタ等の半導体チップでは、大電流化,小型化にともない、高電流密度で使用されることが多くなってきている。   In recent years, power converters have been reduced in size and density. In order to reduce the size and increase the density of the power converter, it is necessary to improve the wiring inside the package, the package structure, the heat dissipation method, and the like. In particular, semiconductor chips such as IGBTs (Insulated Gate Bipolar Transistors), FWDs (Free Wheeling Diodes), power MOSFETs, and power bipolar transistors, which are power devices, may be used at a high current density with an increase in current and size. It is getting more.

ここで問題となるのが高電流密度化にともなう発熱密度の増加である。例えば、従来では定格50Aで使用していた半導体チップに、半導体チップの高性能化にともなって定格以上の電流、例えば75Aの電流を流すという使われ方が多くなってきている。逆に同じ電流を流すのであれば、半導体チップの高性能化により、チップの面積を小さくすることができる。例えば10mm□の半導体チップを1枚のウェハから100個取り出すことができたとすると、半導体チップの高性能化に伴って、その面積を30%小さなもの(約8.4mm□)とすると、同じウェハから取り出すことのできる半導体チップ個数は約142個となり、1ウェハ当たりの半導体チップの取れ数が大きくなる。このように、より小さな半導体チップで、より多くの電流を流すことができれば、1ウェハ当たりの半導体チップの取れ数増加にともない、コスト低減につながる。   The problem here is an increase in heat generation density as the current density increases. For example, a semiconductor chip that has been used at a rating of 50A has been increasingly used to pass a current exceeding the rating, for example, a current of 75A, as the performance of the semiconductor chip increases. Conversely, if the same current is supplied, the area of the chip can be reduced by improving the performance of the semiconductor chip. For example, if 100 semiconductor chips of 10 mm □ can be taken out from a single wafer, the same wafer is assumed if the area is 30% smaller (about 8.4 mm □) as the performance of the semiconductor chip increases. The number of semiconductor chips that can be taken out from the wafer is about 142, and the number of semiconductor chips that can be taken per wafer is increased. In this way, if a larger amount of current can flow with a smaller semiconductor chip, the number of semiconductor chips per wafer increases, leading to cost reduction.

また、半導体チップの小型化は、これらの半導体チップを複数個組み合わせて構成される半導体パッケージのサイズを小さくできるメリットもある。これらのことから、同じ定格電流でも、より小さなチップが嗜好される傾向が強く、結果として高発熱密度化が進んできている現状がある。   Further, downsizing of a semiconductor chip has an advantage that the size of a semiconductor package configured by combining a plurality of these semiconductor chips can be reduced. For these reasons, even with the same rated current, there is a strong tendency to prefer smaller chips, and as a result, there is a current situation in which higher heat generation density is being advanced.

IGBTやFWD等のパワー半導体素子では、動作温度の上限を125℃としている場合が多い。しかしながらチップの小型化や高電流密度化に伴って発熱密度が増加し、従来のアルミワイヤによる配線ではチップ表面の温度上昇を抑えることが不可能となっている。
これは、アルミワイヤが例えば直径が300μmや400μmといった細線であり、チップで発生した熱を移動することが出来ないばかりか、アルミワイヤ自身がジュール発熱により発熱し、場合によっては溶断してしまう問題点がある。
In power semiconductor elements such as IGBT and FWD, the upper limit of the operating temperature is often set to 125 ° C. However, the heat generation density increases with the miniaturization and high current density of the chip, and it is impossible to suppress the temperature rise of the chip surface with the conventional wiring using the aluminum wire.
This is because the aluminum wire is a thin wire having a diameter of, for example, 300 μm or 400 μm, and not only the heat generated by the chip cannot be transferred, but also the aluminum wire itself generates heat due to Joule heat generation, and sometimes melts. There is a point.

片面冷却方式を取る半導体パッケージでは、半導体チップから発生した熱は半導体チップの下面からしか放熱が出来ない。半導体パッケージ内には、絶縁保護のためにシリコーン系の封止樹脂が充填されており、半導体チップの上面はこの封止樹脂で覆われている。シリコーン系封止樹脂の熱伝導率は0.1〜0.2W/mK程度であり、この構成では半導体チップ上面からの放熱は期待できない。   In a semiconductor package that employs a single-sided cooling system, heat generated from a semiconductor chip can be radiated only from the lower surface of the semiconductor chip. The semiconductor package is filled with a silicone-based sealing resin for insulation protection, and the upper surface of the semiconductor chip is covered with this sealing resin. The thermal conductivity of the silicone-based sealing resin is about 0.1 to 0.2 W / mK, and heat dissipation from the upper surface of the semiconductor chip cannot be expected with this configuration.

このような問題点に対し、半導体チップ上面から効率的に熱を逃がす方法として、図6 に示すように、半導体チップ、ここではIGBTチップ上面に金属製のヒートスプレッダを熱伝導性樹脂あるいははんだ材により接合し、最も高温となるチップ中央部の熱をチップ周辺に拡散して最高温度を下げる方法が考案されている(例えば、特許文献1参照)。   As a method for efficiently escaping heat from the upper surface of the semiconductor chip, a metal heat spreader is applied to the upper surface of the semiconductor chip, here the IGBT chip, by using a heat conductive resin or a solder material as shown in FIG. There has been devised a method for lowering the maximum temperature by bonding and diffusing the heat at the center of the chip, which is the highest temperature, to the periphery of the chip (for example, see Patent Document 1).

図7は、従来のIGBTモジュールの要部断面図である。セラミクス51の裏面に裏面銅箔52をを固着し、表面にエミッタ用導体パターン53とコレクタ用導体パターン54およびゲート用導体パターン55を固着した導電パターン月絶縁基板50と、このコレクタ用導体パターン54上にIGBTチップ56をはんだ60により固着し、このIGBTチップ56上面にヒートスプレッダ62をはんだ59により固着し、このヒートスプレッダ62とエミッタ用導体パターン53をアルミワイヤ63で接続し、IGBTチップ56上のゲートパッド58と、ゲート用導体パターン55の間をアルミワイヤ61で接続する。   FIG. 7 is a cross-sectional view of a main part of a conventional IGBT module. A conductive pattern lunar insulating substrate 50 having a back surface copper foil 52 fixed to the back surface of the ceramics 51 and an emitter conductor pattern 53, a collector conductor pattern 54, and a gate conductor pattern 55 fixed to the surface, and the collector conductor pattern 54 An IGBT chip 56 is fixed to the top of the IGBT chip 56 by solder 60, a heat spreader 62 is fixed to the upper surface of the IGBT chip 56 by solder 59, the heat spreader 62 and the emitter conductor pattern 53 are connected by an aluminum wire 63, and a gate on the IGBT chip 56 is connected. An aluminum wire 61 connects between the pad 58 and the gate conductor pattern 55.

また、インバータ動作をさせるには、この他にダイオードが必要であるが、本特許での説明では簡略化のため省略してある。また、図7に示した構造のものは、PPS(ポリ・フェニレン・サルファイド)又はPBT(ポリ・ブチレン・テレフタレート)などの樹脂ケース内に収納され、さらにその中に素子保護としてシリコーン樹脂が充填される。   In addition, in order to perform the inverter operation, a diode is necessary in addition to this, but it is omitted in the description in this patent for the sake of simplicity. Further, the structure shown in FIG. 7 is housed in a resin case such as PPS (polyphenylene sulfide) or PBT (polybutylene terephthalate), and further filled with silicone resin as element protection. The

図8に別の従来のIGBTモジュールの要部断面図を示す。ヒートスプレッダ62上のアルミワイヤ61を、銅やアルミニウムなどの金属板64としたものである。アルミワイヤ61を金属板64とすることで、配線抵抗の低減,配線のジュール発熱の低減,半導体チップから発生した熱の移動が可能となる。   FIG. 8 shows a cross-sectional view of a main part of another conventional IGBT module. The aluminum wire 61 on the heat spreader 62 is a metal plate 64 such as copper or aluminum. By using the aluminum wire 61 as the metal plate 64, the wiring resistance can be reduced, the Joule heat generation of the wiring can be reduced, and the heat generated from the semiconductor chip can be transferred.

このヒートスプレッダ62と金属板64との接合方法として、導電性接着剤による接合、はんだ材による接合、超音波による直接接合などが考えられる。   As a method of joining the heat spreader 62 and the metal plate 64, joining using a conductive adhesive, joining using a solder material, direct joining using ultrasonic waves, or the like can be considered.

また、特許文献2には、半導体チップ上にヒートスプレッダ(導電性の良い金属板)が超音波溶接で接合されていることが記されている。   Patent Document 2 describes that a heat spreader (a metal plate having good conductivity) is joined on a semiconductor chip by ultrasonic welding.

また、特許文献3には、半導体素子に熱的に接続されたヒートスプレッダをレーザ溶接によりプリント配線基板に溶着させることやヒートスプレッダにNiめっきを施すことが記載されている。   Patent Document 3 describes that a heat spreader thermally connected to a semiconductor element is welded to a printed wiring board by laser welding, and Ni plating is applied to the heat spreader.

また、特許文献4には、銅合金の放熱板をリードフレームにYAGレーザで溶接することが記載されている。   Patent Document 4 describes welding a copper alloy heat sink to a lead frame with a YAG laser.

また、特許文献5には、銅線とタングステン製のプローブとを金属材料を介してレーザ溶接にて接合することが記載されている。   Patent Document 5 describes that a copper wire and a tungsten probe are joined by laser welding via a metal material.

また、特許文献6には、銅またはアルミニウムからなる低融点材料と高融点材料からなる接合クラッド板、接合クラッド板をレーザ溶接すること、接合クラッド材の用途としてヒートスプレッダに多用されることが記載されている。
特開2000−307058号公報 特開2004−96135号公報 特開2001−168244号公報([要約] [0027]) 特開平11−191607号公報([要約] [請求項1]) 特開2000−187043号公報([請求項6]) 特開第3272787号公報([請求項1] [0021] [0003])
Patent Document 6 describes that a low-melting-point material made of copper or aluminum and a joining clad plate made of a high-melting-point material, laser welding of the joining clad plate, and a heat spreader that is frequently used as a joint clad material. ing.
JP 2000-307058 A JP 2004-96135 A JP 2001-168244 A ([Summary] [0027]) JP 11-191607 A ([Summary] [Claim 1]) JP 2000-187043 A ([Claim 6]) Japanese Patent Laying-Open No. 3272787 ([Claim 1] [0021] [0003])

しかしながら、図8において、導電性接着剤では、はんだ接合や超音波接合に比べ電気抵抗が大きく、好ましくない。はんだ接合の場合、IGBTチップ56より発せられた熱がヒートスプレッダ62を介して伝導してくるため、はんだ接合が熱劣化し、接合信頼性の確保が難しくなる。また、超音波接合では、ヒートスプレッダ62上に銅板64を重ね、荷重と振動を加えるために、ヒートスプレッダ62とIGBTチップ56を接合しているはんだ59にクラックが生じる場合がある。   However, in FIG. 8, the conductive adhesive is not preferable because it has a larger electric resistance than solder bonding or ultrasonic bonding. In the case of solder bonding, the heat generated from the IGBT chip 56 is conducted through the heat spreader 62, so that the solder bonding is thermally deteriorated and it is difficult to ensure the bonding reliability. In ultrasonic bonding, a copper plate 64 is placed on the heat spreader 62, and a load and vibration are applied, so that cracks may occur in the solder 59 that bonds the heat spreader 62 and the IGBT chip 56.

これを解決するために、レーザ溶接を用いる方法があるのでそれを説明する。   In order to solve this, there is a method using laser welding, which will be described.

図9および図10は、銅のヒートスプレッダと銅板をレーザ溶接する様子を示す図である。これは図8のC部を示す。レーザ射出ユニット65からYAGレーザ(波長1064nm)を照射し、銅板64と銅のヒートスプレッダ62aを溶融し、銅板64と銅のヒートスプレッダ62aを固着する。   9 and 10 are views showing a state in which a copper heat spreader and a copper plate are laser-welded. This shows part C of FIG. The YAG laser (wavelength 1064 nm) is irradiated from the laser emission unit 65, the copper plate 64 and the copper heat spreader 62a are melted, and the copper plate 64 and the copper heat spreader 62a are fixed.

YAGレーザを照射することにより、初めに銅板64表面から溶融が始まる。そして次第に溶融部67が深さ方向に進展していき、銅板64の下側に設置した銅のヒートスプレッダ62aに達することで銅板64と銅のヒートスプレッダ64界面が接合される。   By irradiating the YAG laser, melting starts from the surface of the copper plate 64 first. Then, the melting part 67 gradually advances in the depth direction, and reaches the copper heat spreader 62a installed on the lower side of the copper plate 64 so that the interface between the copper plate 64 and the copper heat spreader 64 is joined.

レーザパワー及びエネルギが低すぎた場合には、図9に示すように溶融部67が銅のヒートスプレッダ62aまで到達させることができず、接合が出来ない。また、レーザパワー及びエネルギが高すぎた場合には、図10に示すように銅板64と銅のヒートスプレッダ62aを貫通してしまい、接合が出来ない。   When the laser power and energy are too low, the melted portion 67 cannot reach the copper heat spreader 62a as shown in FIG. When the laser power and energy are too high, the copper plate 64 and the copper heat spreader 62a are penetrated as shown in FIG.

一方、半導体チップの熱膨張係数と銅などの高熱伝導材からなるヒートスプレッダの熱膨張係数との差異により、冷熱繰り返し環境において、はんだに繰り返し応力が働き、はんだ部にクラックが生じてしまう問題点がある。   On the other hand, due to the difference between the thermal expansion coefficient of the semiconductor chip and the thermal expansion coefficient of the heat spreader made of a high thermal conductivity material such as copper, there is a problem that a repeated stress acts on the solder and a crack occurs in the solder part in a cold and hot environment. is there.

図11にヒートスプレッダの接合構造における、冷熱繰り返し環境でのIGBTチップ及びヒートスプレッダの伸縮挙動を示す図であり、同図(a)は高温時の模式図、同図(b)は低温時の模式図である。同図(a)においては、IGBTチップ56に比べ銅のヒートスプレッダ62aの熱膨張係数の方が大きいため、銅のヒートスプレッダ62aにより左右に引っ張れる形となる。同図(b)においては、反対に銅のヒートスプレッダ62aにより中央に引っ張られる形となる。IGBTモジュールの信頼性試験においては、高温側は125℃、低温側は−40℃の温度条件にて、数百サイクルの繰り返し試験が実施されている。この繰り返し応力によりはんだ59が劣化し、最も応力が大きい箇所からクラックが生じてきてしまう。   FIG. 11 is a diagram showing the expansion and contraction behavior of the IGBT chip and the heat spreader in the heat-repeating environment in the heat spreader joining structure, where FIG. 11 (a) is a schematic diagram at high temperature, and FIG. 11 (b) is a schematic diagram at low temperature. It is. In FIG. 5A, the thermal expansion coefficient of the copper heat spreader 62a is larger than that of the IGBT chip 56, and therefore the copper heat spreader 62a is pulled left and right. In FIG. 5B, the copper heat spreader 62a is pulled to the center. In the reliability test of the IGBT module, repeated tests of several hundred cycles are performed under the temperature condition of 125 ° C. on the high temperature side and −40 ° C. on the low temperature side. The solder 59 deteriorates due to this repeated stress, and a crack is generated from a location where the stress is the largest.

具体的には、シリコンの熱膨張係数は約3×10−6/℃であり、銅の熱膨張係数は16.5×10−6/℃である。これらの熱膨張係数の違いにより、IGBTチップ56と銅のヒートスプレッダ62aとを固着するはんだ59にストレスが加わる。 Specifically, the thermal expansion coefficient of silicon is about 3 × 10 −6 / ° C., and the thermal expansion coefficient of copper is 16.5 × 10 −6 / ° C. Due to the difference in thermal expansion coefficient, stress is applied to the solder 59 for fixing the IGBT chip 56 and the copper heat spreader 62a.

このストレスで発生したクラックが進展した場合、IGBTチップ56からの電流経路が狭まり、配線抵抗増加,導通不良に発展するという不都合が生じる。   When the crack generated by this stress progresses, the current path from the IGBT chip 56 is narrowed, resulting in an inconvenience that the wiring resistance increases and conduction failure occurs.

このようなことから、ヒートスプレッダ62の材質として、熱膨張係数がシリコンに近いモリブデン(熱膨張係数は5.1×10−6/℃)やタングステン(同4.5×10−6/℃)、あるいは銅−モリブデン焼結体(同7〜14×10−6/℃)や銅−タングステン焼結体(同6〜12×10−6/℃)などの低熱膨張係数の金属または焼結体を用いることにより、IGBTチップ56と銅のヒートスプレッダ62a間のはんだ56に加わる熱ストレスを低減することが可能となる。 Therefore, as a material of the heat spreader 62, molybdenum having a thermal expansion coefficient close to that of silicon (thermal expansion coefficient is 5.1 × 10 −6 / ° C.), tungsten (4.5 × 10 −6 / ° C.), Alternatively, a metal or sintered body having a low thermal expansion coefficient, such as a copper-molybdenum sintered body (7 to 14 × 10 −6 / ° C.) or a copper-tungsten sintered body (6 to 12 × 10 −6 / ° C.). By using it, it is possible to reduce the thermal stress applied to the solder 56 between the IGBT chip 56 and the copper heat spreader 62a.

つぎに、ヒートスプレッダ62とIGBTチップ56との熱膨張係数の差を縮めるためにヒートスプレッダ材として銅−モリブデン焼結体を用いた場合について説明する。   Next, a case where a copper-molybdenum sintered body is used as the heat spreader material in order to reduce the difference in thermal expansion coefficient between the heat spreader 62 and the IGBT chip 56 will be described.

図12および図13は、銅板と銅−モリブデン焼結体とをYAGレーザにて溶接した要部断面図である。銅板64の表面にレーザ射出ユニット65から照射されたYAGレーザ66のエネルギにより銅板64が溶融しはじめ、照射時間とともにその溶融部67が銅−モリブデン焼結体62bの表面に近づいていく。しかし、図12に示すように、この溶融部67は銅−モリブデン焼結体62bの表面で停止するか、多少入り込んだ状態としかならない。これは、銅と銅―モリブデン焼結体62bの融点に大きな差があるためである。すなわち、銅の融点は1083℃であるが、モリブデンの融点は2620℃であるため、溶融部67が銅−モリブデン焼結体62b表面に達したとしても、その温度がモリブデンの融点である2620℃になっていない場合には、銅板64と銅−モリブデン焼結体62bの界面で停止してしまう。または、銅−モリブデン焼結体62bの中の銅成分だけが溶融し、溶融部67が銅−モリブデン焼結体62bに少し入り込んだ状態にしかならない。   12 and 13 are cross-sectional views of a main part in which a copper plate and a copper-molybdenum sintered body are welded with a YAG laser. The copper plate 64 begins to melt on the surface of the copper plate 64 by the energy of the YAG laser 66 irradiated from the laser emitting unit 65, and the melting portion 67 approaches the surface of the copper-molybdenum sintered body 62b with the irradiation time. However, as shown in FIG. 12, the melting portion 67 stops at the surface of the copper-molybdenum sintered body 62 b or only enters a slightly intruded state. This is because there is a large difference between the melting points of the copper and the copper-molybdenum sintered body 62b. That is, although the melting point of copper is 1083 ° C., the melting point of molybdenum is 2620 ° C. Therefore, even if the melting part 67 reaches the surface of the copper-molybdenum sintered body 62b, the temperature is 2620 ° C., which is the melting point of molybdenum. Otherwise, it stops at the interface between the copper plate 64 and the copper-molybdenum sintered body 62b. Alternatively, only the copper component in the copper-molybdenum sintered body 62b is melted, and the melted portion 67 only enters the copper-molybdenum sintered body 62b.

このような状態では、銅板64と銅−モリブデン焼結体62bとの所望の接合強度が得られない。そこで、レーザパワー及びエネルギを高くし、溶融部67を銅−モリブデン焼結体62b中に深く入り込ませようとした場合には、図13に示すように、溶融部67の一部がスパッタとして消失して消失部68が発生してしまう問題点がある。このような消失部68が発生した場合、接合強度の低下,電気・熱抵抗の増大が引き起こされ、使用できない。   In such a state, desired bonding strength between the copper plate 64 and the copper-molybdenum sintered body 62b cannot be obtained. Therefore, when the laser power and energy are increased and the molten part 67 is to be deeply inserted into the copper-molybdenum sintered body 62b, a part of the molten part 67 disappears as spatter as shown in FIG. As a result, there is a problem that the disappearing portion 68 occurs. When such a loss | disappearance part 68 generate | occur | produces, the fall of joining strength and the increase in electrical / thermal resistance will be caused, and it cannot be used.

図14および図15に示すように、タングステン焼結体62cとした場合についても同様なことが起きる。すなわち、タングステンの融点は3410℃であるため、銅の融点1083℃に比べ差異がありすぎ、銅−モリブデン焼結体62bと銅板64との接合の場合よりも、接合が困難となる。   As shown in FIG. 14 and FIG. 15, the same thing occurs when the tungsten sintered body 62c is used. That is, since the melting point of tungsten is 3410 ° C., there is too much difference compared to the melting point of copper 1083 ° C., and the bonding becomes more difficult than in the case of bonding the copper-molybdenum sintered body 62b and the copper plate 64.

この発明の目的は、前記の課題を解決して、ヒートスプレッダと外部導出導体である金属板とをレーザ溶接することで、ヒートスプレッダ下のはんだにダメージを与えず、かつ、強固で高い信頼性を持った接合方法を提供するものである。   The object of the present invention is to solve the above-mentioned problems and laser-weld the heat spreader and a metal plate which is an external lead-out conductor so that the solder under the heat spreader is not damaged and has high strength and high reliability. A bonding method is provided.

前記の目的を達成するために、半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダおよび前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して前記ヒートスプレッダと前記金属板とを溶接し、レーザパワー密度が0.4MW/cmを超え、1.5MW/cm未満であり、レーザエネルギーが50Jを超え、150J未満である接合方法とする。 In order to achieve the above object, in a joining method of a heat spreader and a metal plate, wherein the heat spreader and the metal plate are made of copper, overlaid on a heat spreader fixed on a semiconductor chip via a fixing material, and joining the metal plate. A heat spreader having a thickness of 1.5 mm or less and a thickness of the metal plate of 0.5 mm or less; irradiating the metal plate with a YAG laser to weld the heat spreader and the metal plate; A bonding method in which the density is greater than 0.4 MW / cm 2 and less than 1.5 MW / cm 2 , and the laser energy is greater than 50 J and less than 150 J.

また、半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダが銅と銅−モリブデン焼結体の積層体であるクラッド材もしくは銅と銅−タングステン焼結体の積層体であるクラッド材であり、前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して該金属板と前記積層体であるクラッド材の銅とを溶接し、レーザパワー密度が0.4MW/cm を超え、1.5MW/cm 未満であり、レーザエネルギーが50Jを超え、150J未満である接合方法とする。 Moreover, in the joining method of a heat spreader and a metal plate, which is superposed on a heat spreader fixed on a semiconductor chip via a fixing material, and joining the metal plate, the heat spreader is a laminate of copper and a copper-molybdenum sintered body. A clad material or a clad material that is a laminate of copper and a copper-tungsten sintered body, wherein the metal plate is made of copper, the thickness of the heat spreader is 1.5 mm or less, and the thickness of the metal plate is 0.5 mm. The metal plate is irradiated with a YAG laser to weld the metal plate and the copper clad material, and the laser power density exceeds 0.4 MW / cm 2 and 1.5 MW / cm The joining method is less than 2 and the laser energy is more than 50J and less than 150J .

また、半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダが銅とモリブデンの積層体であるクラッド材もしくは銅とタングステンの積層体であるクラッド材を含み、前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して該金属板と前記積層体であるクラッド材の銅とを溶接し、レーザパワー密度が0.4MW/cm を超え、1.5MW/cm 未満であり、レーザエネルギーが50Jを超え、150J未満である接合方法とする。 Further, in a joining method of a heat spreader and a metal plate, which is superposed on a heat spreader fixed on a semiconductor chip via a fixing material, and joining the metal plate, the heat spreader is a clad material or copper which is a laminate of copper and molybdenum. A clad material that is a laminate of tungsten, the metal plate is formed of copper, the heat spreader has a thickness of 1.5 mm or less, the metal plate has a thickness of 0.5 mm or less, and the metal plate has a YAG laser the irradiated by welding the copper clad material which is the laminate with the metal plate, the laser power density exceeds 0.4 mW / cm 2, less than 1.5 MW / cm 2, the laser energy is a 50J It is set as the joining method which is more than 150J .

また、半導体チップ上に固着材を介して固着されたヒートスプレッダの上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダは、モリブデン,タングステン,銅−モリブデンの焼結体,銅−タングステンの焼結体のいずれかであり、該ヒートスプレッダの少なくとも前記金属板との接合面にNiめっき膜を形成し、前記金属板が銅であり、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記ヒートスプレッダのNiめっき膜上に前記金属板を配置し、前記金属板にYAGレーザを照射して該金属板と前記ヒートスプレッダとを溶接し、レーザパワー密度が0.4MW/cm を超え、1.5MW/cm 未満であり、レーザエネルギーが50Jを超え、150J未満である接合方法とする。 Moreover, in the joining method of a heat spreader and a metal plate which overlaps a heat spreader fixed on a semiconductor chip via a fixing material and joins the metal plate, the heat spreader is a sintered body of molybdenum, tungsten or copper-molybdenum. , A copper-tungsten sintered body, a Ni plating film is formed on at least a joint surface of the heat spreader with the metal plate, the metal plate is copper, and the thickness of the heat spreader is 1.5 mm or less. The thickness of the metal plate is 0.5 mm or less, the metal plate is disposed on the Ni plating film of the heat spreader, and the metal plate and the heat spreader are welded by irradiating the metal plate with a YAG laser. , the laser power density exceeds 0.4 mW / cm 2, less than 1.5 MW / cm 2, the laser energy is 50 , Greater and joining method is less than 150 J.

また、前記銅の表面にNiめっき膜が形成されているとよい。   Further, a Ni plating film may be formed on the copper surface.

また、前記金属板に、銅に替えてアルミニウムを用いるとよい。   Moreover, it is good to use aluminum instead of copper for the said metal plate.

本発明によれば、銅のヒートスプレッダと銅板との接合をレーザ溶接し、その溶接条件を所定の条件とすることで、超音波接合のように加圧,振動を加えることが無いために、ヒートスプレッダ下のはんだ及び半導体チップにダメージを与えることが無く、高い接合信頼性を確保できる。   According to the present invention, since the welding of the copper heat spreader and the copper plate is laser-welded and the welding condition is set to a predetermined condition, pressure and vibration are not applied unlike ultrasonic bonding. High bonding reliability can be ensured without damaging the underlying solder and semiconductor chip.

また、銅―モリブデン、銅―タングステンの積層体であるクラッド材をヒートスプレッダとして用い、銅板とヒートスプレッダの銅側とをレーザ溶接し、その溶接条件を所定の条件とすることで、超音波接合のように加圧,振動を加えることが無いために、ヒートスプレッダ下のはんだ及び半導体チップにダメージを与えることが無く、高い接合信頼性を確保できる。   Also, the clad material, which is a copper-molybdenum and copper-tungsten laminate, is used as a heat spreader, the copper plate and the copper side of the heat spreader are laser welded, and the welding conditions are set to predetermined conditions, so that ultrasonic bonding is performed. Since no pressure or vibration is applied to the solder, the solder and the semiconductor chip under the heat spreader are not damaged, and high bonding reliability can be ensured.

さらに、半導体チップと接合するヒートスプレッダは熱膨張係数が小さいモリブデンやタングステンのため、半導体チップが実動作状態においても、ヒートスプレッダと半導体チップを固着するはんだに加わる熱ストレスを小さくできて、クラックの発生を抑制できる。   Furthermore, the heat spreader that joins the semiconductor chip is molybdenum or tungsten with a low coefficient of thermal expansion, so even when the semiconductor chip is in actual operation, the thermal stress applied to the solder that fixes the heat spreader and the semiconductor chip can be reduced, and cracks can be generated. Can be suppressed.

図1は、この発明を適用した半導体装置の構成図であり、同図(a)は要部断面図、同図(b)は同図(a)のA部拡大図である。この図はIGBTモジュールの要部断面図である。   1A and 1B are configuration diagrams of a semiconductor device to which the present invention is applied. FIG. 1A is a cross-sectional view of an essential part, and FIG. 1B is an enlarged view of a portion A of FIG. This figure is a cross-sectional view of the main part of the IGBT module.

セラミクス11の裏面に裏面銅箔12を固着し、表面にエミッタ用導体パターン13とコレクタ用導体パターン14およびゲート用導体パターン15を固着した導電パターン月絶縁基板10と、このコレクタ用導体パターン14上にIGBTチップ6をはんだ16により固着し、このIGBTチップ6上面に銅のヒートスプレッダ1をはんだ7により固着し、この銅のヒートスプレッダ1と外部導出導体である銅板5を所定の条件(詳細は後述の図2の説明を参照のこと)のYAGレーザ19をレーザ射出ユニット18から照射して
溶融し溶融部20で固着する。IGBTチップ6上のゲートパッド9と、ゲート用導体パターン15の間をアルミワイヤ17で接続する。
A conductive pattern lunar insulating substrate 10 having a backside copper foil 12 fixed to the back surface of the ceramics 11 and an emitter conductor pattern 13, a collector conductor pattern 14 and a gate conductor pattern 15 fixed to the surface, and the collector conductor pattern 14 The IGBT chip 6 is fixed to the upper surface of the IGBT chip 6 with the solder 16, and the copper heat spreader 1 is fixed to the upper surface of the IGBT chip 6 with the solder 7. The YAG laser 19 (see the description of FIG. 2) is irradiated from the laser emitting unit 18 and melted and fixed at the melted portion 20. An aluminum wire 17 connects the gate pad 9 on the IGBT chip 6 and the gate conductor pattern 15.

また、インバータ動作をさせるには、この他にダイオードが必要であるが、本特許での説明では簡略化のため省略してある。また、図1に示した構造のものは、PPS(ポリ・フェニレン・サルファイド)又はPBT(ポリ・ブチレン・テレフタレート)などの樹脂ケース内に収納され、さらにその中に素子保護としてシリコーン樹脂が充填される。   In addition, in order to perform the inverter operation, a diode is necessary in addition to this, but it is omitted in the description in this patent for the sake of simplicity. The structure shown in FIG. 1 is housed in a resin case such as PPS (polyphenylene sulfide) or PBT (polybutylene terephthalate), and further filled with a silicone resin as element protection. The

図2は、この発明の第1実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、同図(a)から同図(c)は工程順に示した要部工程断面図である。この図は図1(b)のB部である。   FIG. 2 is a process diagram showing a method of joining a heat spreader and a metal plate according to the first embodiment of the present invention, and FIG. 2 (a) to FIG. . This figure is a portion B of FIG.

銅のヒートスプレッダ1上に外部導出導体である銅板5を配置する(同図(a))。
つぎに、レーザ出射ユニット18の照準を溶融予定個所21に合わせる(同図(b))。
つぎに、レーザ出射ユニット18によりYAGレーザ19を照射し、銅板6と銅のヒートスプレッダ1を溶融して、溶融部20で固着する(同図(c))。
A copper plate 5 serving as an external lead-out conductor is disposed on the copper heat spreader 1 ((a) in the figure).
Next, the aim of the laser emitting unit 18 is adjusted to the planned melting point 21 ((b) in the figure).
Next, the YAG laser 19 is irradiated by the laser emitting unit 18, and the copper plate 6 and the copper heat spreader 1 are melted and fixed at the melting portion 20 (FIG. 3C).

実験によると、銅板5の厚みが0.5mm,銅のヒートスプレッダ1の厚みが1.0mmの場合、ファイバコア径0.4mmでレーザパワー密度1.0MW/cm,エネルギを100Jとした場合、レーザ接合ができる。また、レーザパワー密度を1.5MW/cmkW,エネルギを100Jとした場合には、銅のヒートスプレッダ1の裏面まで溶融部20が貫通してしまい、その溶融した銅はスパッタとして消失してしまったため、接合が不可能であった。 According to the experiment, when the thickness of the copper plate 5 is 0.5 mm and the thickness of the copper heat spreader 1 is 1.0 mm, the fiber core diameter is 0.4 mm, the laser power density is 1.0 MW / cm 2 , and the energy is 100 J. Laser bonding is possible. Further, when the laser power density is 1.5 MW / cm 2 kW and the energy is 100 J, the molten portion 20 penetrates to the back surface of the copper heat spreader 1, and the molten copper disappears as spatter. Therefore, joining was impossible.

さらに、レーザパワー密度を0.4MW/cmとした場合には、溶融部20は銅のヒートスプレッダ1の表面に到達できず、接合が不可能であった。そして、レーザパワー密度を1.0MW/cmとしてエネルギを50Jと低くした場合には、溶融部20の銅のヒートスプレッダ1側への溶け込みが浅く、所望の接合強度が得られなかった。また、レーザパワー密度を1.0MW/cmとしてエネルギを150Jと高くした場合には、溶融部20の銅のヒートスプレッダ1側への溶け込みが深く、所望の接合強度が得られなかった。 Furthermore, when the laser power density was set to 0.4 MW / cm 2 , the melted portion 20 could not reach the surface of the copper heat spreader 1 and could not be joined. When the laser power density was 1.0 MW / cm 2 and the energy was lowered to 50 J, the melting of the molten portion 20 into the copper heat spreader 1 side was so shallow that the desired bonding strength could not be obtained. Further, when the laser power density was 1.0 MW / cm 2 and the energy was increased to 150 J, the melting portion 20 was deeply melted into the heat spreader 1 side, and a desired bonding strength could not be obtained.

そのため、銅板5の厚みが0.5mm以下、銅のヒートスプレッダ1の厚みが1.5mm以下で、レーザパワー密度を0.4Mw/cmを超え、1.5MW/cm未満とし、エネルギーを50Jを超え150J未満とする、適切なレーザパワーとエネルギを選定することで、所望の溶接状態を得ることができる。 Therefore, the thickness of the copper plate 5 is 0.5 mm or less, the thickness of the copper heat spreader 1 is 1.5 mm or less, the laser power density is more than 0.4 Mw / cm 2 and less than 1.5 MW / cm 2 , and the energy is 50 J By selecting an appropriate laser power and energy that is more than and less than 150 J, a desired welding state can be obtained.

上記接合例では、外部導出導体である金属板の材質として銅を用いた場合を述べたが、これを銅合金としても同様な結果が得られる。しかしながら、銅及び銅合金のYAGレーザ(波長1064nm)の吸収率は10%程度しかないため、出射したレーザの90%程度が無駄となってしまう。そこで図3に示すように銅板5(銅及び銅合金)の表面にYAGレーザの吸収率が高いNiめっき膜22を形成した。Niめっき22は少なくともレーザ光が直接照射される部分に形成されていればよいが、より簡便に金属板(銅板5)の全面をめっきしてもよい。NiにおけるYAGレーザの吸収率は約25%であり、銅及び銅合金のそれより2.5倍の吸収率がある。これにより、銅及び銅合金表面にNiめっき膜22を形成せずにYAGレーザを照射する場合よりも低いレーザパワー及びエネルギで所望の溶接状態を得ることが可能となる。   In the above-mentioned joining example, the case where copper is used as the material of the metal plate which is the external lead-out conductor has been described. However, since the absorption rate of copper and copper alloy YAG laser (wavelength 1064 nm) is only about 10%, about 90% of the emitted laser is wasted. Therefore, as shown in FIG. 3, a Ni plating film 22 having a high YAG laser absorption rate was formed on the surface of the copper plate 5 (copper and copper alloy). The Ni plating 22 may be formed at least in a portion directly irradiated with laser light, but the entire surface of the metal plate (copper plate 5) may be more simply plated. The absorption rate of the YAG laser in Ni is about 25%, which is 2.5 times that of copper and copper alloys. Thereby, it becomes possible to obtain a desired welding state with a laser power and energy lower than those in the case of irradiating the YAG laser without forming the Ni plating film 22 on the copper and copper alloy surfaces.

また、超音波接合のように、加圧,振動を加えないために、ヒートスプレッダ1下のはんだ7及びIGBTチップ6にクラックを生じさせることがない。   Further, unlike ultrasonic bonding, no pressurization or vibration is applied, so that cracks are not generated in the solder 7 and the IGBT chip 6 under the heat spreader 1.

この場合のNiめっき膜22の形成は、少なくともレーザ照射面に形成してあれば目的を達成することができるため、必ずしも全面に形成しなくても良い。   The formation of the Ni plating film 22 in this case does not necessarily have to be formed on the entire surface because the purpose can be achieved if it is formed on at least the laser irradiation surface.

しかし、銅のヒートスプレッダ1では、前記したように、温度サイクルやヒートサイクルなどの熱ストレスが印加されるとIGBTチップ6との接合部であるはんだ7にクラックが発生する。それを防止する方法をつぎの実施例で説明する。   However, in the copper heat spreader 1, as described above, when a thermal stress such as a temperature cycle or a heat cycle is applied, a crack is generated in the solder 7 that is a joint portion with the IGBT chip 6. A method for preventing this will be described in the next embodiment.

図4は、この発明の第2実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、同図(a)から同図(c)は工程順に示した要部工程断面図である。この図は銅2aと銅−モリブデン焼結体2bの積層体で形成したクラッド材のヒートスプレッダ2上の銅板5を固着した配線構造を示す。この積層体はクラッド材と呼ばれている。   FIG. 4 is a process diagram showing a method of joining a heat spreader and a metal plate according to a second embodiment of the present invention, and FIG. 4 (a) to FIG. . This figure shows a wiring structure in which a copper plate 5 on a heat spreader 2 of a clad material formed of a laminate of copper 2a and a copper-molybdenum sintered body 2b is fixed. This laminate is called a clad material.

銅2aと銅−モリブデン焼結体2bの積層体で形成したクラッド材のヒートスプレッダ2の銅2a側上に外部導出導体である銅板5を配置する(同図(a))。
つぎに、レーザ出射ユニット18の照準を溶融予定個所21に合わせる(同図(b))。
つぎに、レーザ出射ユニット18によりYAGレーザ19を照射し、銅板5とクラッド材のヒートスプレッダ2の銅2aを溶融して、溶融部20で固着する(同図(c))。
A copper plate 5 as an external lead-out conductor is disposed on the copper 2a side of the heat spreader 2 of the clad material formed of a laminate of the copper 2a and the copper-molybdenum sintered body 2b ((a) in the figure).
Next, the aim of the laser emitting unit 18 is adjusted to the planned melting point 21 ((b) in the figure).
Next, the YAG laser 19 is irradiated by the laser emitting unit 18 to melt the copper plate 5 and the copper 2a of the clad material heat spreader 2 and fix them at the melting part 20 (FIG. 2C).

クラッド材のヒートスプレッダ2は、上側に銅2a、下側に銅−モリブデン焼結体2bが配置された構造である。尚、下側を銅−タングステン焼結体にしてもよい。   The clad heat spreader 2 has a structure in which a copper 2a is disposed on the upper side and a copper-molybdenum sintered body 2b is disposed on the lower side. The lower side may be a copper-tungsten sintered body.

図4(c)に示したように、銅板5とクラッド材のヒートスプレッダ2においては、銅−モリブデン焼結体2bに達する深い溶融部20を得ることができるために、高い接合強度と電気・熱抵抗に優れた溶接構造が実現できる。このクラッド材のヒートスプレッダ2における銅板5と銅−モリブデン焼結体2b(又は銅−タングステン焼結体)の厚さの比率は、必要とする熱膨張係数と銅溶融部の深さにより適宜決めればよい。   As shown in FIG. 4 (c), in the copper plate 5 and the heat spreader 2 made of a clad material, a deep molten portion 20 reaching the copper-molybdenum sintered body 2b can be obtained. A weld structure with excellent resistance can be realized. If the ratio of the thickness of the copper plate 5 and the copper-molybdenum sintered body 2b (or copper-tungsten sintered body) in the heat spreader 2 of this clad material is appropriately determined depending on the required thermal expansion coefficient and the depth of the copper melted part. Good.

また、この場合も第1実施例と同様に銅板5の表面をNiめっき膜を形成してもよい。   Also in this case, a Ni plating film may be formed on the surface of the copper plate 5 as in the first embodiment.

図5は、この発明の第3実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、同図(a)から同図(c)は工程順に示した要部工程断面図である。この図は銅3aとモリブデン3bを積層したクラッド材のヒートスプレッダ3上の配線構造を示す。この積層体はクラッド材と呼ばれているこのモリブデンをタングステンにしてもよい。   FIG. 5 is a process diagram showing a method of joining a heat spreader and a metal plate according to a third embodiment of the present invention, and FIG. 5 (a) to FIG. . This figure shows a wiring structure on a heat spreader 3 of a clad material in which copper 3a and molybdenum 3b are laminated. In this laminated body, this molybdenum called a clad material may be tungsten.

銅3aとモリブデン3bの積層体で形成したクラッド材のヒートスプレッダ3の銅5上に外部導出導体である銅板5を配置する(同図(a))。
つぎに、レーザ出射ユニット18の照準を溶融予定個所21に合わせる(同図(b))。
つぎに、レーザ出射ユニット18によりYAGレーザ19を照射し、銅板3aとクラッド材のヒートスプレッダ3の銅3aを溶融し、溶融部20で固着する(同図(c))。
A copper plate 5 serving as an external lead-out conductor is disposed on the copper 5 of the heat spreader 3 made of a clad material formed of a laminate of copper 3a and molybdenum 3b (FIG. 1A).
Next, the aim of the laser emitting unit 18 is adjusted to the planned melting point 21 ((b) in the figure).
Next, the YAG laser 19 is irradiated by the laser emitting unit 18 to melt the copper plate 3a and the copper 3a of the clad material heat spreader 3 and fix them at the melting part 20 (FIG. 2C).

図5(c)はクラッド材の構成を上側に銅3a、下側にモリブデン3b(又はタングステン)とした場合であり、図4(c)で説明したことと同様な溶融部20を得ることができる。   FIG. 5 (c) shows a case where the clad material is composed of copper 3a on the upper side and molybdenum 3b (or tungsten) on the lower side, and a molten portion 20 similar to that described in FIG. 4 (c) can be obtained. it can.

図6は、この発明の第4実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、同図(a)から同図(c)は工程順に示した要部工程断面図である。4はモリブデンのヒートスプレッダである。少なくとも、モリブデンのヒートスプレッダ4の銅板5との接合面にNiめっき膜22を形成しておく。   FIG. 6 is a process diagram showing a method of joining a heat spreader and a metal plate according to a fourth embodiment of the present invention, and FIGS. . 4 is a heat spreader of molybdenum. At least a Ni plating film 22 is formed on the joint surface of the molybdenum heat spreader 4 with the copper plate 5.

。まず、モリブデンのヒートスプレッダ4の上に外部導出導体である銅板5を配置する(同図(a))。   . First, a copper plate 5 serving as an external lead-out conductor is disposed on a molybdenum heat spreader 4 (FIG. 1A).

つぎにレーザ出射ユニット18の照準を溶融予定箇所21に合わせる(同図(b))。   Next, the aim of the laser emitting unit 18 is aligned with the planned melting point 21 ((b) in the figure).

つぎに、レーザ出射ユニット18によりYAGレーザ19を照射し、銅板5とヒートスプレッダ4の表面のNiめっき膜22とを溶融し、溶融部20で固着する(同図(c))。   Next, the YAG laser 19 is irradiated by the laser emitting unit 18 to melt the copper plate 5 and the Ni plating film 22 on the surface of the heat spreader 4 and fix them at the melting part 20 ((c) in the figure).

ヒートスプレッダ4をモリブデンで形成する場合、ヒートスプレッダの金属板(銅板5)との接合面側にNiめっき膜を設けるのは次の理由による。   When the heat spreader 4 is formed of molybdenum, the Ni plating film is provided on the joint surface side of the heat spreader with the metal plate (copper plate 5) for the following reason.

即ち、金属板(銅板)とモリブデンとは融点ならびにYAGレーザの吸収率が大きく異なる。まず、融点の高いモリブデンを溶融させうるパワーでYAGレーザを照射すると、YAGレーザの照射をうけた銅は融点を大きく上回り、沸点に達すると銅が消失してしまい十分な接合が得られない。また、モリブデンの方がレーザの吸収率が高いため、照射されたレーザがモリブデンに達すると一気にパワーを吸収してしまい、モリブデンを突き抜けてしまうことがある。したがって、銅とモリブデンをレーザ溶接することは困難であり、またレーザのパワーも銅を溶融させうる程度に設定せざるを得ない。   That is, the metal plate (copper plate) and molybdenum are greatly different in melting point and YAG laser absorption. First, when a YAG laser is irradiated with a power capable of melting molybdenum having a high melting point, the copper subjected to the YAG laser greatly exceeds the melting point, and when the boiling point is reached, the copper disappears and a sufficient bonding cannot be obtained. In addition, since molybdenum has a higher laser absorptivity, when the irradiated laser reaches molybdenum, the power is absorbed at a stretch and the molybdenum may be penetrated. Therefore, it is difficult to laser weld copper and molybdenum, and the laser power must be set to such an extent that copper can be melted.

Niはモリブデンほどレーザの吸収率が高くなく、また融点も高くないので、モリブデンの表面にNiめっき膜を設けておき、Niめっき膜に達するパワーでレーザを照射することにより、銅とNiが溶融して結合層を形成することができる。   Ni does not have a higher laser absorptivity and melting point than molybdenum, so a Ni plating film is provided on the surface of molybdenum, and the laser is irradiated with power that reaches the Ni plating film, so that copper and Ni melt. Thus, a bonding layer can be formed.

上記において、モリブデンのヒートスプレッダを例に説明したが、モリブデンをタングステン,銅−モリブデンの焼結体,銅−タングステンの焼結体のいずれかにしてもよく、Niめっき膜を設ける理由も同様である。   In the above, the heat spreader of molybdenum has been described as an example, but molybdenum may be any of tungsten, a copper-molybdenum sintered body, and a copper-tungsten sintered body, and the reason for providing the Ni plating film is also the same. .

また、図4〜図6においても、前記の図3で説明したように、銅板5の表面にNiめっき膜を形成すことにより、YAGレーザの吸収率を高めることが可能である。   4 to 6, as described in FIG. 3, it is possible to increase the absorption rate of the YAG laser by forming a Ni plating film on the surface of the copper plate 5.

尚、前記第1実施例〜第4実施例で外部導出導体である金属板を銅板で説明したが、これをアルミニウム板に替えてもよい。そのときはレーザ溶接条件の最適化が必要となるが、アルミニウムはレーザの吸収率が銅に比べて高いためレーザ照射面にNiめっき膜を形成しなくてもよい。また、レーザはYAGレーザの場合について説明したが、半導体レーザであっても構わない。   In addition, although the metal plate which is an external lead-out conductor was demonstrated with the copper plate in the said 1st Example-4th Example, you may replace this with an aluminum plate. At that time, the laser welding conditions need to be optimized. However, since aluminum has a higher laser absorption rate than copper, it is not necessary to form a Ni plating film on the laser irradiation surface. Further, although the case where the laser is a YAG laser has been described, it may be a semiconductor laser.

この発明を適用した半導体装置の構成図であり、(a)は要部断面図、(b)は同図(a)のA部拡大図BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the semiconductor device to which this invention is applied, (a) is principal part sectional drawing, (b) is the A section enlarged view of the same figure (a). この発明の第1実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、(a)から(c)は工程順に示した要部工程断面図It is process drawing which shows the joining method of the heat spreader and metal plate of 1st Example of this invention, (a) to (c) is principal part process sectional drawing shown in process order 銅表面にNiめっき膜22を形成したヒートスプレッダの要部断面図Cross-sectional view of the main part of a heat spreader in which a Ni plating film 22 is formed on the copper surface この発明の第2実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、(a)から(c)は工程順に示した要部工程断面図It is process drawing which shows the joining method of the heat spreader and metal plate of 2nd Example of this invention, (a) to (c) is principal part process sectional drawing shown in process order この発明の第3実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、(a)から(c)は工程順に示した要部工程断面図It is process drawing which shows the joining method of the heat spreader and metal plate of 3rd Example of this invention, (a) to (c) is principal part process sectional drawing shown in process order この発明の第4実施例のヒートスプレッダと金属板との接合方法を示す工程図であり、(a)から(c)は工程順に示した要部工程断面図It is process drawing which shows the joining method of the heat spreader and metal plate of 4th Example of this invention, (a) to (c) is principal part process sectional drawing shown in process order 従来のIGBTモジュールの要部断面図Sectional view of the main part of a conventional IGBT module 別の従来のIGBTモジュールの要部断面図Sectional drawing of the principal part of another conventional IGBT module 銅のヒートスプレッダと銅板をレーザ溶接する様子を示す図The figure which shows a mode that a copper heat spreader and a copper plate are laser-welded 銅のヒートスプレッダと銅板をレーザ溶接する様子を示す図The figure which shows a mode that a copper heat spreader and a copper plate are laser-welded ヒートスプレッダの接合構造における、冷熱繰り返し環境でのIGBTチップ及びヒートスプレッダの伸縮挙動を示す図であり、(a)は高温時の模式図、(b)は低温時の模式図It is a figure which shows the expansion-contraction behavior of the IGBT chip | tip and a heat spreader in a cold-heat repetition environment in the joining structure of a heat spreader, (a) is a schematic diagram at the time of high temperature, (b) is a schematic diagram at the time of a low temperature. 銅板と銅−モリブデン焼結体とをYAGレーザにて溶接した要部断面図Cross-sectional view of the principal part where a copper plate and copper-molybdenum sintered body are welded with a YAG laser 銅板と銅−モリブデン焼結体とをYAGレーザにて溶接した要部断面図Cross-sectional view of the principal part where a copper plate and copper-molybdenum sintered body are welded with a YAG laser 銅板とタングステン焼結体とをYAGレーザにて溶接した要部断面図Cross-sectional view of the main part where a copper plate and tungsten sintered body are welded with a YAG laser 銅板とタングステン焼結体とをYAGレーザにて溶接した要部断面図Cross-sectional view of the main part where a copper plate and tungsten sintered body are welded with a YAG laser

符号の説明Explanation of symbols

1 銅のヒートスプレッダ
2 クラッド材のヒートスプレッダ
2a 銅
2b 銅−モリブデン焼結体
3 クラッド材のヒートスプレッダ/モリブデン
3a 銅
3b モリブデン
4 ヒートスプレッダ
5 銅板
6 IGBTチップ
7 はんだ
8 エミッタ電極
9 ゲートパッド
10 導電パターン付き絶縁基板
11 セラミクス
12 裏面銅箔
13 エミッタ用導体パターン
14 コレクタ用導体パターン
15 ゲート用導電パターン
16 はんだ
17 アルミワイヤ
18 レーザ出射ユニット
19 YAGレーザ
20 溶融部
21 溶融予定個所
22 Niめっき膜
DESCRIPTION OF SYMBOLS 1 Copper heat spreader 2 Clad heat spreader 2a Copper 2b Copper-molybdenum sintered body 3 Clad heat spreader / molybdenum 3a Copper 3b Molybdenum 4 Heat spreader 5 Copper plate 6 IGBT chip 7 Solder 8 Emitter electrode 9 Gate pad 10 Insulating substrate with conductive pattern DESCRIPTION OF SYMBOLS 11 Ceramics 12 Back surface copper foil 13 Conductor pattern for emitter 14 Conductor pattern for collector 15 Conductive pattern for gate 16 Solder 17 Aluminum wire 18 Laser emission unit 19 YAG laser 20 Melting part 21 Planned melting point 22 Ni plating film

Claims (3)

半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダおよび前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して前記ヒートスプレッダと前記金属板とを溶接し、レーザパワー密度が0.4MW/cmを超え、1.5MW/cm未満であり、レーザエネルギーが50Jを超え、150J未満であることを特徴とするヒートスプレッダと金属板との接合方法。 In a joining method of a heat spreader and a metal plate, which is superposed on a heat spreader fixed on a semiconductor chip via a fixing material and joining a metal plate, the heat spreader and the metal plate are made of copper, and the thickness of the heat spreader is 1 0.5 mm or less, and the thickness of the metal plate is 0.5 mm or less. The metal plate is irradiated with a YAG laser to weld the heat spreader and the metal plate, and the laser power density is 0.4 MW / cm 2 . A method for joining a heat spreader and a metal plate, characterized in that the heat energy is less than 1.5 MW / cm 2 and the laser energy is more than 50 J and less than 150 J. 半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダが銅と銅−モリブデン焼結体の積層体であるクラッド材もしくは銅と銅−タングステン焼結体の積層体であるクラッド材であり、前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して該金属板と前記積層体であるクラッド材の銅とを溶接し、レーザパワー密度が0.4MW/cmを超え、1.5MW/cm未満であり、レーザエネルギーが50Jを超え、150J未満であることを特徴とするヒートスプレッダと金属板との接合方法。 In a method of joining a heat spreader and a metal plate, which is superposed on a heat spreader fixed on a semiconductor chip via a fixing material, and joining the metal plate, the heat spreader is a clad material which is a laminate of copper and a copper-molybdenum sintered body. Or it is a clad material which is a laminated body of copper and a copper-tungsten sintered body, the metal plate is formed of copper, the thickness of the heat spreader is 1.5 mm or less, and the thickness of the metal plate is 0.5 mm or less. There is irradiated with YAG laser welding and copper clad material which is the laminate with the metal plate to the metal plate, the laser power density exceeds 0.4 mW / cm 2, less than 1.5 MW / cm 2 A method for joining a heat spreader and a metal plate, wherein the laser energy is more than 50 J and less than 150 J. 半導体チップ上に固着材を介して固着されたヒートスプレッダ上に重ねて金属板を接合するヒートスプレッダと金属板との接合方法において、前記ヒートスプレッダが銅とモリブデンの積層体であるクラッド材もしくは銅とタングステンの積層体であるクラッド材を含み、前記金属板が銅で形成され、前記ヒートスプレッダの厚みが1.5mm以下で、前記金属板の厚みが0.5mm以下であり、前記金属板にYAGレーザを照射して該金属板と前記積層体であるクラッド材の銅とを溶接し、レーザパワー密度が0.4MW/cmを超え、1.5MW/cm未満であり、レーザエネルギーが50Jを超え、150J未満であることを特徴とするヒートスプレッダと金属板との接合方法。 In a joining method of a heat spreader and a metal plate, which is superposed on a heat spreader fixed on a semiconductor chip via a fixing material, and joining the metal plate, the heat spreader is a clad material or a copper-tungsten which is a laminate of copper and molybdenum. The clad material is a laminate, the metal plate is made of copper, the heat spreader has a thickness of 1.5 mm or less, the metal plate has a thickness of 0.5 mm or less, and the metal plate is irradiated with a YAG laser. and then welding the copper clad material which is the laminate with the metal plate, the laser power density exceeds 0.4 mW / cm 2, less than 1.5 MW / cm 2, the laser energy exceeds 50 J, A joining method of a heat spreader and a metal plate, characterized by being less than 150 J.
JP2005361624A 2005-12-15 2005-12-15 Joining method between heat spreader and metal plate Expired - Fee Related JP4976688B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005361624A JP4976688B2 (en) 2005-12-15 2005-12-15 Joining method between heat spreader and metal plate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005361624A JP4976688B2 (en) 2005-12-15 2005-12-15 Joining method between heat spreader and metal plate

Publications (2)

Publication Number Publication Date
JP2007165690A JP2007165690A (en) 2007-06-28
JP4976688B2 true JP4976688B2 (en) 2012-07-18

Family

ID=38248230

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005361624A Expired - Fee Related JP4976688B2 (en) 2005-12-15 2005-12-15 Joining method between heat spreader and metal plate

Country Status (1)

Country Link
JP (1) JP4976688B2 (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5239291B2 (en) * 2007-10-24 2013-07-17 富士電機株式会社 Semiconductor device and manufacturing method thereof
WO2009081723A1 (en) * 2007-12-20 2009-07-02 Fuji Electric Device Technology Co., Ltd. Semiconductor device and method for manufacturing the same
JP5124056B1 (en) 2011-03-14 2013-01-23 パナソニック株式会社 Laser bonding parts
WO2013021983A1 (en) * 2011-08-10 2013-02-14 富士電機株式会社 Semiconductor device and method for manufacturing same
JP6475918B2 (en) 2014-02-05 2019-02-27 ローム株式会社 Power module
DE102016108656A1 (en) * 2016-05-11 2017-11-16 Danfoss Silicon Power Gmbh Power electronic assembly with vibration-free contacting
DE112018002384T5 (en) 2017-05-10 2020-01-16 Rohm Co., Ltd. Power semiconductor device and manufacturing process for the same
CN110476237B (en) * 2017-10-19 2023-06-02 富士电机株式会社 Semiconductor device and method for manufacturing semiconductor device
WO2020071185A1 (en) * 2018-10-02 2020-04-09 ローム株式会社 Semiconductor device and method for manufacturing semiconductor device
JP7277030B2 (en) * 2019-09-02 2023-05-18 株式会社ディスコ Workpiece processing method
JP2021146359A (en) * 2020-03-18 2021-09-27 三菱マテリアル株式会社 Joined body and method for manufacturing joined body
TW202215664A (en) * 2020-08-07 2022-04-16 日商Flosfia股份有限公司 Semiconductor element and semiconductor device
TW202211484A (en) * 2020-08-07 2022-03-16 日商Flosfia股份有限公司 Semiconductor element and semiconductor device
DE102022206267A1 (en) 2022-06-22 2023-12-28 Robert Bosch Gesellschaft mit beschränkter Haftung Contact system with a power semiconductor and a connecting element

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04230063A (en) * 1990-12-27 1992-08-19 Aichi Steel Works Ltd Multilayer heat sink
KR970005712B1 (en) * 1994-01-11 1997-04-19 삼성전자 주식회사 High heat sink package
JP2000156439A (en) * 1998-11-20 2000-06-06 Mitsubishi Electric Corp Power semiconductor module
JP3238906B2 (en) * 1999-03-19 2001-12-17 株式会社日立製作所 Semiconductor device
JP4160889B2 (en) * 2003-09-30 2008-10-08 富士通株式会社 Manufacturing method of semiconductor device

Also Published As

Publication number Publication date
JP2007165690A (en) 2007-06-28

Similar Documents

Publication Publication Date Title
JP4976688B2 (en) Joining method between heat spreader and metal plate
JP4645406B2 (en) Semiconductor device
JP4775327B2 (en) Manufacturing method of semiconductor device
JP4858238B2 (en) Laser welding member and semiconductor device using the same
US20070262387A1 (en) Power semiconductor module
JP5023604B2 (en) Semiconductor device
JP5103863B2 (en) Semiconductor device
JP2015119072A (en) Laser welding method, laser welding jig, and semiconductor device
JP4764983B2 (en) Manufacturing method of semiconductor device
JP2009105266A (en) Method of manufacturing semiconductor apparatus
JPWO2017195625A1 (en) Semiconductor device and manufacturing method of semiconductor device
JP4765853B2 (en) Manufacturing method of semiconductor device
JP7319295B2 (en) semiconductor equipment
JP6945418B2 (en) Semiconductor devices and manufacturing methods for semiconductor devices
JP6877600B1 (en) Semiconductor device
JP2009105267A (en) Semiconductor apparatus, and method of manufacturing the same
JP2011134949A (en) Semiconductor device
JP5899952B2 (en) Semiconductor module
JP5119139B2 (en) Semiconductor device and manufacturing method of semiconductor device
JP4096741B2 (en) Semiconductor device
JP2019212808A (en) Manufacturing method of semiconductor device
JP4586508B2 (en) Semiconductor device and manufacturing method thereof
JP2019133965A (en) Semiconductor device and manufacturing method thereof
JP5840102B2 (en) Power semiconductor device
JP2007305620A (en) Manufacturing method of semiconductor device

Legal Events

Date Code Title Description
A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A711

Effective date: 20080204

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20081015

RD02 Notification of acceptance of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7422

Effective date: 20081216

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20090212

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20090219

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20091112

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20101019

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20101217

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110118

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110315

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20110405

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20110422

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110705

A911 Transfer to examiner for re-examination before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20110712

A912 Re-examination (zenchi) completed and case transferred to appeal board

Free format text: JAPANESE INTERMEDIATE CODE: A912

Effective date: 20110805

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20120309

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20120413

R150 Certificate of patent or registration of utility model

Ref document number: 4976688

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20150420

Year of fee payment: 3

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees