WO2021193378A1 - 半導体装置用ボンディングワイヤ - Google Patents

半導体装置用ボンディングワイヤ Download PDF

Info

Publication number
WO2021193378A1
WO2021193378A1 PCT/JP2021/011217 JP2021011217W WO2021193378A1 WO 2021193378 A1 WO2021193378 A1 WO 2021193378A1 JP 2021011217 W JP2021011217 W JP 2021011217W WO 2021193378 A1 WO2021193378 A1 WO 2021193378A1
Authority
WO
WIPO (PCT)
Prior art keywords
wire
bonding wire
noble metal
bonding
concentration
Prior art date
Application number
PCT/JP2021/011217
Other languages
English (en)
French (fr)
Inventor
基稀 江藤
大造 小田
宇野　智裕
哲哉 小山田
Original Assignee
日鉄マイクロメタル株式会社
日鉄ケミカル＆マテリアル株式会社
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 日鉄マイクロメタル株式会社, 日鉄ケミカル＆マテリアル株式会社 filed Critical 日鉄マイクロメタル株式会社
Priority to CN202180022853.3A priority Critical patent/CN115362537A/zh
Priority to KR1020227031913A priority patent/KR20220153593A/ko
Priority to JP2022510054A priority patent/JPWO2021193378A1/ja
Priority to EP21776531.2A priority patent/EP4130310A1/en
Priority to US17/913,365 priority patent/US20230148306A1/en
Publication of WO2021193378A1 publication Critical patent/WO2021193378A1/ja

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/04—Alloys based on copper with zinc as the next major constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means 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
    • H01L24/42—Wire connectors; Manufacturing methods related thereto
    • H01L24/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L24/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/10—Electroplating with more than one layer of the same or of different metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0607—Wires
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/50—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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/85—Methods 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 wire connector
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/34—Pretreatment of metallic surfaces to be electroplated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45101—Material 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 less than 400°C
    • H01L2224/45109—Indium (In) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45117—Material 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
    • H01L2224/45118—Zinc (Zn) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45117—Material 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
    • H01L2224/45123—Magnesium (Mg) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45138—Material 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
    • H01L2224/45139—Silver (Ag) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45138—Material 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
    • H01L2224/45147—Copper (Cu) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45138—Material 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
    • H01L2224/45155—Nickel (Ni) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45138—Material 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
    • H01L2224/4516—Iron (Fe) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45163—Material 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 1550°C
    • H01L2224/45166—Titanium (Ti) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45163—Material 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 1550°C
    • H01L2224/45169—Platinum (Pt) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45163—Material 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 1550°C
    • H01L2224/45173—Rhodium (Rh) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material 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
    • H01L2224/45163—Material 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 1550°C
    • H01L2224/45178—Iridium (Ir) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45565—Single coating layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45601—Material 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 less than 400°C
    • H01L2224/45609—Indium (In) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45617—Material 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
    • H01L2224/45618—Zinc (Zn) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45617—Material 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
    • H01L2224/45623—Magnesium (Mg) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45638—Material 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
    • H01L2224/45639—Silver (Ag) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45638—Material 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
    • H01L2224/45644—Gold (Au) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45638—Material 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
    • H01L2224/45655—Nickel (Ni) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45638—Material 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
    • H01L2224/4566—Iron (Fe) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45663—Material 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 1550°C
    • H01L2224/45664—Palladium (Pd) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45663—Material 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 1550°C
    • H01L2224/45666—Titanium (Ti) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45663—Material 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 1550°C
    • H01L2224/45669—Platinum (Pt) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45663—Material 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 1550°C
    • H01L2224/45673—Rhodium (Rh) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/4554—Coating
    • H01L2224/45599—Material
    • H01L2224/456—Material 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
    • H01L2224/45663—Material 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 1550°C
    • H01L2224/45678—Iridium (Ir) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means 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
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/484—Connecting portions
    • H01L2224/4847—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
    • H01L2224/48472—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/85—Methods 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 wire connector
    • H01L2224/85053—Bonding environment
    • H01L2224/85095—Temperature settings
    • H01L2224/85099—Ambient temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means 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
    • H01L24/42—Wire connectors; Manufacturing methods related thereto
    • H01L24/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L24/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30—Technical effects
    • H01L2924/35—Mechanical effects
    • H01L2924/351—Thermal stress
    • H01L2924/3512—Cracking
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30—Technical effects
    • H01L2924/36—Material effects
    • H01L2924/365—Metallurgical effects

Definitions

  • the present invention relates to a bonding wire for a semiconductor device. Furthermore, the present invention relates to a method for manufacturing a semiconductor device using the bonding wire, and a semiconductor device including the bonding wire.
  • the bonding wire for wedge bonding having a diameter of less than 100 ⁇ m is a bonding wire mainly made of aluminum (Al) that can be bonded at room temperature (25 ⁇ 10 ° C.) (hereinafter, also simply referred to as “Al wire”. ) Is mainly used (for example, Patent Document 1).
  • the bonding wire is exposed to an environment containing ionic impurities and moisture.
  • the corrosion of the Al wire progresses remarkably, and it becomes difficult to maintain the joining reliability.
  • the Al wire is easy to recrystallize due to its physical characteristics and has a large coefficient of thermal expansion, so that it is difficult to apply it to high temperature applications.
  • a bonding wire for ball bonding a copper (Cu) wire coated with palladium (Pd) is known (for example, Japanese Patent Application Laid-Open No. 2005-167020), and such a Pd-coated Cu wire is used for wedge bonding. If so, it was confirmed that bonding at room temperature was difficult. Although it is possible to obtain sufficient bonding strength by heating at the time of bonding, oxidation due to heating, generation of thermal stress on each member due to heating and cooling, and time for heating are also required. Therefore, the usage is limited.
  • An object of the present invention is to provide a bonding wire which exhibits good bondability even when applied to wedge bonding at room temperature and also has excellent bonding reliability.
  • the present invention includes the following contents.
  • a core material made of Cu or a Cu alloy hereinafter referred to as "Cu core material”
  • a coating containing a noble metal provided on the surface of the Cu core material hereinafter referred to as "precious metal coating”
  • precious metal coating It is a bonding wire for a semiconductor device having A bonding wire for a semiconductor device having a Cu concentration of 30 to 80 at% on the surface of the wire.
  • the maximum concentration of noble metal in the noble metal coating is obtained by measuring by Auger electron spectroscopy (AES) under the following ⁇ conditions> while digging down from the surface of the wire in the depth direction by Ar sputtering.
  • AES Auger electron spectroscopy
  • Positioning is performed so that the center of the width of the wire is the center of the width of the measurement surface, the width of the measurement surface is 10% or more and 15% or less of the wire diameter, and the length of the measurement surface is the width of the measurement surface.
  • first additive element Concentration of the first additive element with respect to the entire wire containing one or more elements selected from the group consisting of Ni, Zn, Rh, In, Ir and Pt (hereinafter referred to as "first additive element”).
  • first additive element Containing one or more elements selected from the group consisting of P, B, Be, Fe, Mg, Ti, Zn, Ag and Si (hereinafter referred to as "second additive element"), with respect to the entire wire.
  • second additive element Containing one or more elements selected from the group consisting of P, B, Be, Fe, Mg, Ti, Zn, Ag and Si
  • the bonding wire for a semiconductor device of the present invention is A core material made of Cu or a Cu alloy (hereinafter, also referred to as “Cu core material”), and a coating containing a noble metal provided on the surface of the Cu core material (hereinafter, also referred to as “precious metal coating”).
  • Cu core material made of Cu or a Cu alloy
  • precious metal coating a coating containing a noble metal provided on the surface of the Cu core material
  • Pd-coated Cu wire is known as a bonding wire for ball bonding, but when such a Pd-coated Cu wire is used for wedge bonding, it has been confirmed that bonding at room temperature is difficult.
  • the Pd-coated Cu wire for ball bonding has a high-concentration Pd coating on the wire surface in order to suppress oxidation during ball formation.
  • sufficient bonding strength is achieved by diffusion bonding between Cu and the electrode metal.
  • a Pd-coated Cu wire for ball bonding is used for wedge bonding at room temperature (25 ⁇ 10 ° C.), it is sufficient because the high-concentration Pd coating existing on the wire surface suppresses diffusion bonding between Cu and the electrode metal.
  • the present inventors have made a Cu wire having a noble metal coating. It has been found that by increasing the Cu concentration on the surface, good bondability is exhibited even when applied to wedge bonding at room temperature. Not only that, it has also been found that a Cu wire having a noble metal coating and having a Cu concentration on the surface within a predetermined range can realize good bonding reliability even when a semiconductor device is manufactured by resin encapsulation. ..
  • the present invention remarkably contributes to the practical use of Cu-based wires in wedge bonding applications that also cover room temperature bonding, and contributes to the realization of inexpensive and high-performance semiconductor devices.
  • the bonding wire for semiconductor devices of the present invention (hereinafter, also simply referred to as “wire of the present invention” or “wire”) has a surface.
  • the lower limit of the Cu concentration is 30 at% or more, preferably 35 at% or more, more preferably 40 at% or more, 42 at% or more, 44 at% or more, or 45 at% or more.
  • the present inventors have confirmed that when the Cu concentration on the surface is in such a range, an excellent effect such as suppressing the progress of galvanic corrosion can be obtained even when applied to high temperature applications.
  • the present inventors have found that when the Cu concentration on the surface is 45 at% or more, exceptionally excellent bondability can be realized when applied to wedge bonding at room temperature.
  • the Cu concentration on the surface is more preferably 46 at% or more, 48 at% or more, 50 at% or more, or more than 50 at%.
  • the upper limit of the Cu concentration on the surface is from the viewpoint of achieving good bonding reliability even when a semiconductor device is manufactured by resin encapsulation, especially from the viewpoint of achieving good bonding reliability even in a high temperature and high humidity environment. , 80 at% or less, preferably 75 at% or less, more preferably 70 at% or less, 65 at% or less, or 60 at% or less.
  • the Cu concentration on the surface can be determined by measuring with Auger electron spectroscopy (AES) using the wire surface as the measurement surface. Specifically, the composition of the wire surface is analyzed by Auger electron spectroscopy (AES).
  • AES Auger electron spectroscopy
  • gas components such as carbon (C), sulfur (S), oxygen (O), nitrogen (N), non-metal elements, etc. are not considered.
  • the position and dimensions of the measurement surface are determined as follows.
  • the width of the measurement surface means the dimension of the measurement surface in the direction perpendicular to the wire axis (the thickness direction of the wire), and the length of the measurement surface is the direction of the wire axis (the length direction of the wire). ) Refers to the dimensions of the measurement surface.
  • the measurement surface is positioned so that the center of the width of the wire in the direction perpendicular to the wire axis is the center of the width of the measurement surface, and the width of the measurement surface is 10% or more and 15% or less of the wire diameter.
  • the length of the measurement surface is set to be 5 times the width of the measurement surface.
  • the Cu concentration on the above surface is based on the result measured under the conditions described in the [Composition analysis of wire surface by Auger electron spectroscopy (AES)] column described later.
  • the wire of the present invention includes a core material made of Cu or a Cu alloy, that is, a Cu core material.
  • the Cu core material is not particularly limited as long as it is made of Cu or a Cu alloy, and a known Cu core material constituting a conventional Pd-coated Cu wire known as a bonding wire for ball bonding may be used.
  • the Cu core material may contain, for example, one or more dopants selected from the first additive element and the second additive element described later. The preferred contents of these dopants are as described below.
  • the Cu core material consists of Cu and unavoidable impurities.
  • the Cu core material comprises Cu, one or more elements selected from the first and second additive elements described below, and unavoidable impurities.
  • unavoidable impurities for Cu core materials also includes elements constituting the noble metal coating described later.
  • Cu has the property of easily diffusing at high temperatures when contained in other metals.
  • the wire of the present invention having a Cu core material and a noble metal coating on the surface of the Cu core material, when heat treatment is performed at the time of manufacturing the Cu core material, Cu in the Cu core material diffuses in the noble metal coating and reaches the wire surface. be able to.
  • the wire of the present invention is characterized in that the Cu concentration on the surface is within a predetermined range, and the Cu on the surface of the wire may be Cu that has reached the surface by such diffusion.
  • the state of Cu on the surface is not particularly limited, and a part of the Cu may be oxidized or a part of the Cu may be solid-solved in the noble metal in the noble metal coating.
  • the average crystal grain size in the cross section of the Cu core material (C cross section of the Cu core material) in the direction perpendicular to the wire axis is when applied to wedge bonding at room temperature (furthermore, the load at the time of bonding and ultrasonic waves). From the viewpoint of achieving extremely good bondability (even when the conditions are reduced), it is preferably 1.4 ⁇ m or more, more preferably 1.5 ⁇ m or more, 1.6 ⁇ m or more, 1.8 ⁇ m or more, or 2 ⁇ m. That is all.
  • the upper limit of the average crystal grain size is preferably 3.2 ⁇ m or less, more preferably 3.1 ⁇ m or less or 3 ⁇ m or less, from the viewpoint of achieving good loop shape stability.
  • the average crystal grain size in the cross section of the Cu core material C is 1.4 to 3.2 ⁇ m.
  • the average crystal grain size is the diameter when the area of each crystal grain is determined using a measurement method such as backscattered electron diffraction (EBSD: Electron Backscatter Diffraction) method and the area of each crystal grain is regarded as a circle. Take the average.
  • EBSD Electron Backscatter Diffraction
  • the average crystal grain size of the Cu core material C cross section can be measured by the method described in [Measurement of the average crystal grain size of the Cu core material C cross section] described later.
  • the wire of the present invention includes a noble metal-containing coating provided on the surface of the Cu core material, that is, a noble metal coating.
  • the noble metal contained in the noble metal coating is not particularly limited as long as the effect of the present invention is not impaired, but from the viewpoint that extremely good joining reliability can be realized even when the semiconductor device is manufactured by resin encapsulation. It preferably contains palladium (Pd) or gold (Au). More preferably, it is palladium (Pd).
  • the content of Pd is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass. That is all.
  • the upper limit of the content is not particularly limited and may be 100% by mass, but may be, for example, 99% by mass or less, 98% by mass or less, 97% by mass or less.
  • the noble metal coating may further contain, for example, one or more dopants selected from the first additive element and the second additive element described later.
  • dopants selected from the first additive element and the second additive element described later. The preferred contents of these dopants are as described below.
  • the noble metal coating comprises a noble metal and unavoidable impurities.
  • the noble metal coating comprises a noble metal, one or more elements selected from the first and second additive elements described below, and unavoidable impurities.
  • the term "unavoidable impurities" for the noble metal coating also includes elements constituting the Cu core material.
  • the maximum of precious metals in precious metal coatings from the viewpoint of achieving good bonding reliability even when semiconductor devices are manufactured by resin encapsulation, especially from the viewpoint of achieving good bonding reliability even in a high temperature and high humidity environment.
  • the concentration is preferably 50 at% or more. From the viewpoint of achieving extremely good joining reliability even in a high temperature and high humidity environment, the maximum concentration is more preferably 60 at% or more, 70 at% or more, 75 at% or more, or 80 at% or more.
  • the upper limit of the maximum concentration is not particularly limited and may be 100 at%, but may be, for example, 99.5 at% or less, 99 at% or less, 98 at% or less.
  • the thickness of the noble metal coating is 20 nm or more while satisfying the suitable conditions for the maximum concentration, the bonding reliability is extremely excellent even in a high temperature and high humidity environment. It is suitable because it can be realized.
  • the thickness of the noble metal coating is more preferably 25 nm or more, still more preferably 30 nm or more, 35 nm or more, 40 nm or more, 45 nm or more, or 50 nm or more.
  • the thickness of the noble metal coating is preferably 0.5 ⁇ m or less, more preferably 0.4 ⁇ m or less, 0.3 ⁇ m or less, 0.2 ⁇ m or less, 0.15 ⁇ m or less, or 0.1 ⁇ m or less.
  • the maximum concentration of the noble metal in the noble metal coating can be obtained by performing composition analysis by Auger electron spectroscopy (AES) while digging down from the surface of the wire in the depth direction by Ar sputtering.
  • AES Auger electron spectroscopy
  • a concentration profile in the depth direction can be obtained by repeating 1) sputtering treatment with Ar and 2) surface composition analysis after the sputtering treatment, and can be obtained from the concentration profile.
  • the surface composition analysis after the sputtering treatment can be carried out under the same conditions as the composition analysis by Auger electron spectroscopy (AES) when determining the Cu concentration on the surface. That is, when the composition of the surface after the sputtering treatment is analyzed by Auger electron spectroscopy (AES), the position and dimensions of the measurement surface are determined as follows.
  • AES Auger electron spectroscopy
  • the length of the measurement surface is set to be 5 times the width of the measurement surface.
  • the concentration profile in the depth direction obtained for the wire of the present invention according to the embodiment will be described below. From the surface of the wire to a certain depth position, the Cu concentration tends to decrease and the noble metal concentration tends to increase. Further in the depth direction, the concentration of the noble metal tends to decrease and the Cu concentration tends to increase at a certain depth position (d). In such a concentration profile, paying attention to the increase / decrease in the concentration of the noble metal, the maximum concentration of the noble metal can be obtained from the position where the concentration of the noble metal becomes the maximum (in the above embodiment, the depth position d).
  • the noble metal coating contains a plurality of noble metals, it is sufficient to pay attention to the increase / decrease in the total concentration of the plurality of noble metals when determining the "maximum concentration of the noble metals".
  • the noble metal coating contains Pd alone, attention may be paid to an increase or decrease in the concentration of Pd, and when the noble metal coating contains a combination of Pd and Au, attention may be paid to an increase or decrease in the total concentration of Pd and Au.
  • the above-mentioned preferable range of the maximum concentration of the noble metal in the noble metal coating is based on the result of measurement under the conditions described in the [Acquisition of concentration profile in the depth direction by Auger electron spectroscopy (AES)] column described later. ..
  • the noble metal coating may contain gold (Au) in addition to Pd.
  • Au gold
  • the noble metal coating exhibits excellent bondability when applied to wedge bonding at room temperature, and can realize a bonding wire having excellent bonding reliability. can.
  • the content of Au is preferably 0.5% by mass or more, more preferably 1% by mass or more, 1.5 by mass, assuming that the total amount of noble metals contained in the noble metal coating is 100% by mass. It is mass% or more or 2 mass% or more.
  • the upper limit of the content may be, for example, 10% by mass or less, 7% by mass or less, 5% by mass or less, or 3% by mass or less from the viewpoint of avoiding an excessive cost increase.
  • the position showing the maximum concentration of Au in the noble metal coating is closer to the surface side than the position showing the maximum concentration of Pd from the viewpoint of further enjoying the effect of the present invention. Is preferable.
  • the concentration profile in the depth direction obtained above it is sufficient to pay attention to the increase / decrease in the concentration of Au and the increase / decrease in the concentration of Pd separately and independently.
  • the boundary between the Cu core material and the noble metal coating is determined based on the total concentration of the noble metal. With the position where the total concentration of the noble metal is 20 at% as a boundary, the region where the total concentration of the noble metal is 20 at% or more is determined to be the noble metal coating, and the region where the total concentration of the noble metal is less than 20 at% is determined to be the Cu core material. Even if the total concentration of the noble metal is less than 20 at%, the phase (layer) existing on the wire surface side of the noble metal coating according to the above determination is determined to be a noble metal coating.
  • the concentration profile in the depth direction obtained by Auger electron spectroscopy was confirmed from the wire axis to the wire surface, and the total concentration of the noble metal reached 20 at% for the first time. It can be obtained as the distance from the depth position to the wire surface position.
  • the thickness of the noble metal coating described above is based on the result of converting the unit of depth into SiO 2 based on the concentration profile in the depth direction obtained by Auger electron spectroscopy (AES).
  • the wire of the present invention may further contain one or more elements (“first additive element”) selected from the group consisting of Ni, Zn, Rh, In, Ir and Pt.
  • first additive element selected from the group consisting of Ni, Zn, Rh, In, Ir and Pt.
  • the total concentration of the first additive element with respect to the entire wire is preferably 0.1% by mass or more. As a result, the progress of galvanic corrosion can be further suppressed even when applied to high-temperature applications, and a bonding wire having exceptionally excellent bonding reliability can be realized.
  • the total concentration of the first additive element with respect to the entire wire is more preferably 0.3% by mass or more, and further preferably 0.5% by mass or more.
  • the upper limit of the total concentration of the first additive element is preferably 1.5% by mass or less from the viewpoint of suppressing the hardening of the wire and easily achieving good bondability when applied to wedge bonding at room temperature. It is more preferably 1.4% by mass or less, 1.3% by mass or less, or 1.2% by mass or less. Therefore, in a preferred embodiment, the wire of the present invention contains the first additive element, and the concentration of the first additive element with respect to the entire wire is 0.1 to 1.5% by mass in total. Alternatively, for the first additive element, the concentration of Ni with respect to the entire wire may be less than 0.1% by mass, for example, 0.09% by mass or less, 0.08% by mass or less, and the like. ..
  • the wire of the present invention further comprises one or more elements selected from the group consisting of P, B, Be, Fe, Mg, Ti, Zn, Ag, and Si (hereinafter, also referred to as "second additive element"). May contain.
  • the total concentration of the second additive element with respect to the entire wire is preferably 0.1 mass ppm or more. As a result, it is possible to realize a wire having further excellent loop shape stability.
  • the total concentration of the second additive element with respect to the entire wire is more preferably 1 mass ppm or more, 2 mass ppm or more, 3 mass ppm or more, 5 mass ppm or more, 8 mass ppm or more, 10 mass ppm or more, 20 mass.
  • the upper limit of the total concentration of the second additive element is preferably 200 mass ppm or less, preferably 190 mass ppm or less, from the viewpoint of suppressing the hardening of the wire and easily achieving good bondability when applied to wedge bonding at room temperature. It is more preferably ppm or less, 180 mass ppm or less, 170 mass ppm or less, 160 mass ppm or less, or 150 mass ppm or less.
  • the content of the first additive element and the second additive element in the wire can be measured by the method described in [Measurement of element content] described later.
  • the diameter of the wire of the present invention is not particularly limited and may be appropriately determined according to a specific purpose, but is preferably 15 ⁇ m or more, 18 ⁇ m or more, 20 ⁇ m or more, or the like.
  • the upper limit of the diameter is not particularly limited and may be, for example, 200 ⁇ m or less, 150 ⁇ m or less, 100 ⁇ m or less, and the like.
  • high-purity (4N to 6N; 99.99 to 99.9999% by mass or more) raw material copper is continuously cast to a large diameter (diameter of about 3 to 6 mm) to obtain an ingot.
  • the addition method includes, for example, a method of containing it in a Cu core material, a method of containing it in a noble metal coating, and a method of adding it to the surface of the Cu core material. Examples thereof include a method of adhering to the surface of the noble metal coating and a method of adhering to the surface of the noble metal coating, and a plurality of these methods may be combined. Regardless of which addition method is adopted, the effect of the present invention can be exhibited.
  • the Cu core material may be produced by using a copper alloy containing the dopant in a required concentration as a raw material.
  • a dopant When a dopant is added to Cu as a raw material to obtain such a copper alloy, a high-purity dopant component may be directly added to Cu, or a mother alloy containing about 1% of a dopant component may be used. ..
  • the dopant In the method of incorporating the dopant in the noble metal coating, the dopant may be contained in the noble metal plating bath (in the case of wet plating) or the target material (in the case of dry plating) when forming the noble metal coating.
  • the method of depositing on the surface of the Cu core material or the surface of the noble metal coating (1) application of an aqueous solution ⁇ drying ⁇ heat treatment, with the surface of the Cu core material or the surface of the noble metal coating as the adherend surface.
  • One or more adhesion treatments selected from 2) plating method (wet type) and (3) thin film deposition method (dry type) may be carried out.
  • a large-diameter ingot is forged, rolled, and drawn to produce a wire made of Cu or a Cu alloy having a diameter of about 0.9 to 1.2 mm (hereinafter, also referred to as "intermediate wire").
  • Electroplating, electroless plating, vapor deposition, etc. can be used as a method for forming a noble metal coating on the surface of the Cu core material, but it is industrially preferable to use electroplating that can stably control the film thickness. ..
  • an Au coating may be formed on the surface of the Pd coating after the Pd coating is formed on the surface of the intermediate wire.
  • the Pd coating and Au coating may also be applied at the stage of a large-diameter ingot, or after the intermediate wire is drawn and further thinned (for example, the diameter of the final Cu core material is reached). After that), a Pd coating and an Au coating may be formed on the surface of the Cu core material.
  • the wire drawing process can be performed using a continuous wire drawing device that can set a plurality of diamond-coated dies. If necessary, heat treatment may be performed in the middle of the wire drawing process. Pd and Au may be diffused from each other by heat treatment to form a noble metal coating containing an alloy of Au and Pd.
  • a method of promoting alloying by continuously sweeping the wires in an electric furnace at a constant furnace temperature at a constant speed is preferable because the composition and thickness of the alloy can be reliably controlled.
  • the surface modification heat treatment is preferably carried out at a high temperature for a long time from the viewpoint of easily realizing a bonding wire having a Cu concentration in a predetermined range on the surface.
  • the time of the surface modification heat treatment is preferably 5 seconds or longer, more preferably 7 seconds or longer or 10 seconds or longer.
  • the upper limit of the heat treatment time can be, for example, 20 seconds or less.
  • a hydrogen-containing inert gas is preferable, and examples thereof include hydrogen-containing helium gas, hydrogen-containing nitrogen gas, and hydrogen-containing argon gas.
  • the hydrogen concentration in the hydrogen-containing inert gas may be, for example, in the range of 1 to 20%.
  • the atmospheric gas on the surface modification heat treatment is forming gas (5% H 2 -N 2) .
  • an inert gas such as nitrogen gas or argon gas may be used as the atmospheric gas under strict control of the temperature and time during the heat treatment.
  • the wire of the present invention can be used to connect a first electrode on a semiconductor element and a second electrode on a lead frame or a circuit board in the manufacture of a semiconductor device.
  • the first connection (1st junction) with the first electrode on the semiconductor element and the second connection (2nd junction) with the second electrode on the lead frame or the circuit board may both be wedge junctions.
  • the wire of the present invention having a noble metal coating and having a Cu concentration on the surface in a predetermined range can realize good bondability even when wedge-bonded at room temperature. Therefore, the wire of the present invention can be suitably used for wedge bonding (specifically, for wedge-wedge bonding), and also suitably for room temperature wedge bonding (specifically, for room temperature wedge-wedge bonding). can do.
  • a semiconductor device can be manufactured by connecting an electrode on a semiconductor element with an electrode on a lead frame or a circuit board using the bonding wire for a semiconductor device of the present invention.
  • the method for manufacturing a semiconductor device of the present invention comprises a first electrode on a semiconductor element and a second electrode on a lead frame or a circuit board. Including the step of connecting with the wire of the present invention, both the first connection between the first electrode and the wire of the present invention and the second connection between the second electrode and the wire of the present invention are carried out by wedge joining. It is a feature.
  • the wire part is crimped onto the electrode by applying ultrasonic waves and pressure without forming a ball.
  • the wire of the present invention having a noble metal coating and having a Cu concentration on the surface within a predetermined range can realize good bondability even when wedge-bonded at room temperature. Therefore, in one preferred embodiment, in the method of the present invention, the first connection and the second connection are carried out at room temperature.
  • the wire of the present invention having a noble metal coating and having a Cu concentration on the surface within a predetermined range can realize good bonding reliability even when a semiconductor device is manufactured by resin encapsulation. Therefore, in a preferred embodiment, the method of the present invention further comprises the step of sealing the resin after wedge bonding.
  • a known thermosetting resin composition for example, epoxy resin composition
  • the wire of the present invention good bonding reliability can be advantageously realized regardless of the specifications of the thermosetting resin composition.
  • a semiconductor device can be manufactured by connecting an electrode on a semiconductor element with an electrode on a lead frame or a circuit board using the bonding wire for a semiconductor device of the present invention.
  • the semiconductor device of the present invention includes a circuit board, a semiconductor element, and a bonding wire for conducting the circuit board and the semiconductor element, and the bonding wire is the wire of the present invention. ..
  • the circuit board and the semiconductor element are not particularly limited, and a known circuit board and the semiconductor element that can be used to form the semiconductor device may be used.
  • a lead frame may be used instead of the circuit board.
  • the semiconductor device may be configured to include a lead frame and a semiconductor element mounted on the lead frame.
  • Semiconductor devices are used in electrical products (for example, computers, mobile phones, digital cameras, televisions, air conditioners, solar power generation systems, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircraft, etc.). Various semiconductor devices can be mentioned.
  • the raw material was loaded into a carbon crucible, using a high frequency furnace, it was dissolved by heating to 1090 ⁇ 1500 ° C. in an inert atmosphere, such as during or N 2 or Ar gas vacuum, by continuous casting It was manufactured by processing it to a large diameter and then thinning it to the final wire diameter by wire drawing.
  • the obtained core material of copper or copper alloy with a diameter of 3 to 6 mm is drawn to a diameter of 0.9 to 1.2 mm, and then continuously drawn with a die. , Further reduced the diameter of the wire.
  • a commercially available lubricating liquid was used, and the wire drawing speed was set to 20 to 150 m / min.
  • a pickling treatment with hydrochloric acid was performed, and then a Pd coating was formed so as to cover the entire surface of the Cu alloy of the core material. Further, some wires (Examples No. 1 to 6, 9 to 14, 17 to 28, Comparative Examples No. 1 to 4) formed an Au coating on the Pd coating.
  • An electrolytic plating method was used to form the Pd coating and the Au coating.
  • a commercially available plating solution was used as the Pd plating solution and the Au plating solution.
  • wire drawing was further performed, and the wire was processed to the final wire diameter of ⁇ 35 ⁇ m.
  • heat treatment at 300 to 700 ° C. for 2 to 15 seconds was performed 0 to 2 times during the wire drawing process.
  • surface modification heat treatment was performed.
  • the heat treatment temperature of the surface modification heat treatment was 500 to 750 ° C.
  • the wire feeding speed was 30 to 100 m / min
  • the heat treatment time was 2 to 15 seconds.
  • the heat treatment methods of the intermediate heat treatment and the surface modification heat treatment were carried out while continuously sweeping the wires and flowing Ar gas.
  • Test / evaluation method The test / evaluation method will be described below.
  • the Cu concentration on the wire surface was determined by measuring the wire surface as a measurement surface by Auger electron spectroscopy (AES) as follows. First, the bonding wire used for measurement was linearly fixed to the sample holder. Next, the center of the width of the wire in the direction perpendicular to the longitudinal axis of the wire is positioned so as to be the center of the width of the measurement surface, and the width of the measurement surface is measured so as to be 10% or more and 15% or less of the wire diameter. The face was decided. The length of the measuring surface was 5 times the width of the measuring surface.
  • the composition of the wire surface was analyzed under the condition of an acceleration voltage of 10 kV, and the surface Cu concentration (at%) was determined.
  • the composition analysis by AES was carried out on three measurement surfaces separated from each other by 1 mm or more in the longitudinal direction of the wire, and the average value thereof was adopted.
  • gas components such as carbon (C), sulfur (S), oxygen (O), nitrogen (N), non-metal elements, etc. were not considered.
  • the concentration profile in the depth direction of the wire was obtained by analyzing the composition of the wire surface by AES and then performing the composition analysis by AES while digging from the surface of the wire in the depth direction by Ar sputtering. Specifically, the concentration profile in the depth direction was obtained by repeating 1) sputtering treatment with Ar and 2) surface composition analysis after the sputtering treatment after the composition analysis of the wire surface by AES. The sputtering treatment of 1) was performed with Ar + ions and an acceleration voltage of 1 kV.
  • the dimensions of the measurement surface and the conditions of the composition analysis by AES were the same as those described in the above-mentioned [Composition analysis of wire surface by Auger electron spectroscopy (AES)] column.
  • the concentration profile in the depth direction was obtained for three measurement surfaces separated from each other by 1 mm or more in the longitudinal direction of the wire.
  • the concentration profile was confirmed from the wire axis toward the wire surface, and the thickness of the noble metal coating was defined as the distance from the depth position where the total concentration of the precious metal reached 20 at% for the first time to the wire surface position. I asked for it. The average value of the numerical values obtained for the three measurement surfaces was adopted as the thickness of the precious metal coating. The thickness of the noble metal coating was determined by converting the unit of depth into SiO 2 based on the concentration profile in the depth direction.
  • the contents of the first additive element and the second additive element in the wire were analyzed as the concentration of the element contained in the entire wire by using an ICP emission spectrophotometer and an ICP mass spectrometer.
  • ICP-OES PS3520U VDDII” manufactured by Hitachi High-Tech Science Co., Ltd.
  • ICP-MS Alignment 7700x ICP-MS manufactured by Agilent Technologies America Co., Ltd.
  • the average crystal grain size of the Cu core material C cross section is measured by using an electron backscatter diffraction (EBSD) method (measurement device EBSD analysis system "AZtec HKL” manufactured by Oxford Instruments Co., Ltd.). Specifically, the area of each crystal grain was obtained for the entire cross section of the Cu core material C, the area of each crystal grain was converted into the area of a circle, and the average of the diameters was calculated, and this was calculated as the average crystal grain. The area of each crystal grain was determined by defining the position where the orientation difference between adjacent measurement points was 15 degrees or more as the grain boundary.
  • EBSD electron backscatter diffraction
  • Evaluation criteria ⁇ : 100 gf or more ⁇ : 75 gf or more and less than 100 gf ⁇ : 50 gf or more and less than 75 gf ⁇ : 50 gf or less
  • the joining reliability was evaluated by both a high temperature and high humidity test (HAST) and a high temperature storage life test (HTSL).
  • HAST high temperature and high humidity test
  • HTSL high temperature storage life test
  • a sample wedge-bonded at room temperature to an electrode provided by forming a 3.0 ⁇ m-thick Al-0.5 mass% Cu alloy on a silicon substrate is sealed with a commercially available thermosetting epoxy resin, and the bonding reliability is achieved.
  • a sample for a sex test was prepared. The prepared sample for bonding reliability evaluation was exposed to a high temperature and high humidity environment at a temperature of 130 ° C. and a relative humidity of 85% using an unsaturated pressure cooker tester, and biased at 7 V.
  • the joint life of the wedge joint was set to the time when the shear strength value of the wedge joint was halved from the initially obtained share strength by conducting the share test of the wedge joint every 48 hours. As the value of the share strength, the average value of the measured values at 50 points of the wedge joint selected at random was used.
  • the shear test was performed after removing the resin by acid treatment to expose the wedge joint. Then, it was evaluated according to the following criteria.
  • the sample for bonding reliability evaluation prepared in the same procedure as above was exposed to an environment at a temperature of 175 ° C. using a high temperature incubator.
  • the joining life of the wedge joint was set to the time when the pull test of the wedge joint was carried out every 500 hours and the pull strength value became 1/2 of the initially obtained pull strength.
  • the pull strength value the average value of the measured values at 50 points of the wedge joint selected at random was used.
  • the pull test after the high temperature standing test was performed after removing the resin by acid treatment to expose the wedge joint. Then, it was evaluated according to the following criteria.
  • loop shape stability (reproducibility of the loop profile) was evaluated from the standard deviation of the maximum loop height by connecting 100 trapezoidal loops so that the loop length was 2 mm and the loop height was 300 ⁇ m. An optical microscope was used for height measurement, and evaluation was performed according to the following criteria.
  • ⁇ : 3 ⁇ is less than 20 ⁇ m ⁇ : 3 ⁇ is 20 ⁇ m or more and less than 25 ⁇ m ⁇ : 3 ⁇ is 25 ⁇ m or more
  • Table 1 shows the evaluation results of Examples and Comparative Examples.
  • Example No. Each of 1 to 37 has a noble metal coating provided on the surface of the Cu core material, the Cu concentration on the surface is within the range of the present invention, and exhibits good bondability in wedge bonding at room temperature, and is also bonded. It was confirmed that it is also excellent in reliability.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Wire Bonding (AREA)

Abstract

常温でのウェッジ接合に適用しても良好な接合性を呈し、また、接合信頼性にも優れる半導体装置用ボンディングワイヤを提供する。該ボンディングワイヤは、Ｃｕ又はＣｕ合金からなる芯材（以下、「Ｃｕ芯材」という。）、及び該Ｃｕ芯材の表面に設けられた貴金属を含有する被覆、を有し、該ワイヤの表面におけるＣｕ濃度が３０～８０ａｔ％である。

Description

半導体装置用ボンディングワイヤ
　本発明は、半導体装置用ボンディングワイヤに関する。さらには、該ボンディングワイヤを用いた半導体装置の製造方法、及び、該ボンディングワイヤを含む半導体装置に関する。
　半導体装置では、半導体素子上に形成された電極と、リードフレームや基板上の電極との間をボンディングワイヤによって接続している。直径が１００μｍ未満のウェッジ接合用ボンディングワイヤとしては、常温（２５±１０℃）での接合が可能であるアルミニウム（Ａｌ）を主な材質とするボンディングワイヤ（以下、単に「Ａｌワイヤ」ともいう。）が主として用いられている（例えば、特許文献１）。
　他方、半導体装置のパッケージ（封止）技術に関し、従来は金属、ガラス及び／又はセラミックスで気密封止されていたが、コストや量産性の観点から、熱硬化性エポキシ樹脂を用いた樹脂封止が用いられるようになってきている。
特表２０１６－５１１５２９号公報
　半導体装置の封止技術の変遷に伴い、従来の気密封止とは異なり、ボンディングワイヤは、イオン性の不純物や水分を含む環境に曝されることとなる。そのような環境では、Ａｌワイヤの腐食が顕著に進行し、接合信頼性を維持することが困難となっている。また、Ａｌワイヤは、その物性上、再結晶し易く、熱膨張率も大きいため、高温用途への適用は困難である。
　ボール接合用ボンディングワイヤとしては、パラジウム（Ｐｄ）により被覆された銅（Ｃｕ）ワイヤが知られているが（例えば、特開２００５－１６７０２０号公報）、斯かるＰｄ被覆Ｃｕワイヤをウェッジ接合に用いた場合、常温での接合は困難であることを確認した。接合時に加熱することで十分な接合強度を得ることは可能であるものの、加熱による酸化や、加熱・冷却に起因した各部材への熱応力の発生、さらに加熱のための時間も必要となることから、用途が限定されてしまう。
　また、被覆を有しないベアＣｕワイヤに関しては、常温でのウェッジ接合において接合初期は十分な接合強度を呈するものの、電極接合部における腐食の進行により良好な接合信頼性は得られない。
　本発明は、常温でのウェッジ接合に適用しても良好な接合性を呈し、また、接合信頼性にも優れるボンディングワイヤを提供することを課題とする。
　上記課題につき鋭意検討した結果、下記構成を有するボンディングワイヤによって上記課題を解決できることを見出し、斯かる知見に基づいて更に検討を重ねることによって本発明を完成した。
　すなわち、本発明は以下の内容を含む。
［１］　Ｃｕ又はＣｕ合金からなる芯材（以下、「Ｃｕ芯材」という。）、及び
　該Ｃｕ芯材の表面に設けられた貴金属を含有する被覆（以下、「貴金属被覆」という。）、
を有する半導体装置用ボンディングワイヤであって、
　該ワイヤの表面におけるＣｕ濃度が３０～８０ａｔ％である、半導体装置用ボンディングワイヤ。
［２］　表面におけるＣｕ濃度が、下記＜条件＞にてオージェ電子分光法（ＡＥＳ：Auger　Electron　Spectroscopy）により測定される、［１］に記載のボンディングワイヤ。
＜条件＞ワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下、測定面の長さが測定面の幅の５倍である
［３］　貴金属被覆がＰｄを含む、［１］又は［２］に記載のボンディングワイヤ。
［４］　貴金属被覆がさらにＡｕを含む、［３］に記載のボンディングワイヤ。
［５］　貴金属被覆における貴金属の最大濃度が５０ａｔ％以上である、［１］～［４］の何れかに記載のボンディングワイヤ。
［６］　貴金属被覆におけるＡｕの最大濃度を示す位置がＰｄの最大濃度を示す位置よりも表面側にある、［４］又は［５］に記載のボンディングワイヤ。
［７］　貴金属被覆における貴金属の最大濃度が、ワイヤの表面からＡｒスパッタにより深さ方向に掘り下げていきながら、下記＜条件＞にてオージェ電子分光法（ＡＥＳ）により測定して得られる深さ方向の濃度プロファイルから求められる、［５］又は［６］に記載のボンディングワイヤ。
＜条件＞ワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下、測定面の長さが測定面の幅の５倍である
［８］　Ｃｕ芯材が、Ｃｕと不可避不純物からなる、［１］～［７］の何れかに記載のボンディングワイヤ。
［９］　貴金属被覆が、貴金属と不可避不純物からなる、［１］～［８］の何れかに記載のボンディングワイヤ。
［１０］　Ｎｉ、Ｚｎ、Ｒｈ、Ｉｎ、Ｉｒ及びＰｔからなる群から選択される１種以上の元素（以下、「第１添加元素」という。）を含み、ワイヤ全体に対する第１添加元素の濃度が総計で０．１～１．５質量％である、［１］～［７］の何れかに記載のボンディングワイヤ。
［１１］　Ｐ、Ｂ、Ｂｅ、Ｆｅ、Ｍｇ、Ｔｉ、Ｚｎ、Ａｇ及びＳｉからなる群から選択される１種以上の元素（以下、「第２添加元素」という。）を含み、ワイヤ全体に対する第２添加元素の濃度が総計で０．１～２００質量ｐｐｍである、［１］～［７］、［１０］の何れかに記載のボンディングワイヤ。
［１２］　Ｃｕ芯材が、Ｃｕと、第１添加元素及び第２添加元素から選択される１種以上の元素と、不可避不純物からなる、［１０］又は［１１］に記載のボンディングワイヤ。
［１３］　貴金属被覆が、貴金属と、第１添加元素及び第２添加元素から選択される１種以上の元素と、不可避不純物からなる、［１０］～［１２］の何れかに記載のボンディングワイヤ。
［１４］　ワイヤ軸に垂直方向のＣｕ芯材断面における平均結晶粒径が１．４～３．２μｍである、［１］～［１３］の何れかに記載のボンディングワイヤ。
［１５］　ウェッジ－ウェッジ接合用である、［１］～［１４］の何れかに記載のボンディングワイヤ。
［１６］　半導体素子上の第１電極と、リードフレーム又は回路基板上の第２電極とを、［１］～［１５］の何れかに記載のボンディングワイヤにより接続する工程を含み、
　第１電極とボンディングワイヤとの第１接続と、第２電極とボンディングワイヤとの第２接続の両方をウェッジ接合により実施する、半導体装置の製造方法。
［１７］　第１接続と第２接続を常温下で実施する、［１６］に記載の方法。
［１８］　［１］～［１５］の何れかに記載のボンディングワイヤを含む半導体装置。
　本発明によれば、常温でのウェッジ接合に適用しても良好な接合性を呈し、また、接合信頼性にも優れるボンディングワイヤを提供することができる。
　以下、本発明をその好適な実施形態に即して詳細に説明する。
　［半導体装置用ボンディングワイヤ］
　本発明の半導体装置用ボンディングワイヤは、
　Ｃｕ又はＣｕ合金からなる芯材（以下、「Ｃｕ芯材」ともいう。）、及び
　該Ｃｕ芯材の表面に設けられた貴金属を含有する被覆（以下、「貴金属被覆」ともいう。）、
を有し、
　該ワイヤの表面におけるＣｕ濃度が３０～８０ａｔ％であることを特徴とする。
　先述のとおり、ボール接合用ボンディングワイヤとしてＰｄ被覆Ｃｕワイヤが知られているが、斯かるＰｄ被覆Ｃｕワイヤをウェッジ接合に用いた場合、常温での接合は困難であることを確認した。ボール接合用のＰｄ被覆Ｃｕワイヤでは、ボール形成時の酸化を抑制すべく、ワイヤ表面に高濃度のＰｄ被覆を有している。他方、Ｃｕワイヤを用いたボンディングでは、Ｃｕと電極金属との拡散接合により十分な接合強度が達成される。ボール接合用のＰｄ被覆Ｃｕワイヤを常温（２５±１０℃）でのウェッジ接合に用いると、ワイヤ表面に存在する高濃度のＰｄ被覆によりＣｕと電極金属との拡散接合が抑制されるため十分な接合が得られないものと推察される。接合時に加熱することで十分な接合強度を得ることは可能であるものの、加熱による酸化や、加熱・冷却に起因した各部材への熱応力の発生、さらに加熱のための時間も必要となることから、用途が限定されてしまう。Ａｌワイヤや、被覆を有しないベアＣｕワイヤの適用も考えられるが、これらのワイヤに関しては、先述のとおり、良好な接合信頼性が得られ難いという課題がある。
　本発明者らは、常温でのウェッジ接合に適用しても良好な接合性を呈し、また、接合信頼性にも優れるボンディングワイヤを提供すべく鋭意検討する過程において、貴金属被覆を有するＣｕワイヤについて表面のＣｕ濃度を高めることにより、常温でのウェッジ接合に適用しても良好な接合性を呈することを見出した。そればかりか、貴金属被覆を有すると共に表面のＣｕ濃度が所定範囲にあるＣｕワイヤでは、樹脂封止により半導体装置を製造した場合であっても、良好な接合信頼性を実現し得ることも見出した。貴金属被覆を有することにより、接合界面に貴金属が或る程度の濃度にて存在する領域が存在し、斯かる貴金属含有領域により電極接合部における腐食の進行が顕著に抑制されたものと推察される。さらには、パワー半導体装置など装置の作動サイクルに伴う温度変化の著しい用途への適用においても、Ｃｕを主な材料とすることから、Ａｌワイヤで課題となる熱応力に起因した接続部界面・近傍におけるクラック（ボンドクラックやヒールクラック）の発生も顕著に抑制し得る。このように、本発明は、常温接合をも対象とするウェッジ接合用途におけるＣｕ系ワイヤの実用化に著しく寄与するものであり、安価かつ高性能な半導体装置の実現に寄与するものである。
　常温でのウェッジ接合に適用しても良好な接合性を実現する観点から、本発明の半導体装置用ボンディングワイヤ（以下、単に「本発明のワイヤ」、「ワイヤ」ともいう。）において、表面におけるＣｕ濃度の下限は、３０ａｔ％以上であり、好ましくは３５ａｔ％以上、より好ましくは４０ａｔ％以上、４２ａｔ％以上、４４ａｔ％以上又は４５ａｔ％以上である。表面におけるＣｕ濃度が斯かる範囲にあると、高温用途に適用した場合であってもガルバニック腐食の進行を抑制し得るといった優れた効果も奏することを本発明者らは確認している。
　特に表面におけるＣｕ濃度が４５ａｔ％以上であると、常温でのウェッジ接合に適用した場合に格別優れる接合性を実現できることを本発明者らは見出した。表面におけるＣｕ濃度は、さらに好ましくは４６ａｔ％以上、４８ａｔ％以上、５０ａｔ％以上又は５０ａｔ％超である。
　表面におけるＣｕ濃度の上限は、樹脂封止により半導体装置を製造した場合であっても良好な接合信頼性を実現する観点、とりわけ高温高湿環境下においても良好な接合信頼性を実現する観点から、８０ａｔ％以下であり、好ましくは７５ａｔ％以下、より好ましくは７０ａｔ％以下、６５ａｔ％以下又は６０ａｔ％以下である。
　本発明において、表面におけるＣｕ濃度は、ワイヤ表面を測定面として、オージェ電子分光法（ＡＥＳ）により測定して求めることができる。詳細には、オージェ電子分光法（ＡＥＳ）により、ワイヤ表面の組成分析を行う。ここで、表面におけるＣｕ濃度を求めるにあたり、炭素（Ｃ）、硫黄（Ｓ）、酸素（Ｏ）、窒素（Ｎ）等ガス成分、非金属元素等は考慮しない。
　オージェ電子分光法（ＡＥＳ）によりワイヤ表面の組成分析を行うにあたり、測定面の位置及び寸法は、以下のとおり決定する。なお、以下において、測定面の幅とは、ワイヤ軸に垂直な方向（ワイヤの太さ方向）における測定面の寸法をいい、測定面の長さとは、ワイヤ軸の方向（ワイヤの長さ方向）における測定面の寸法をいう。
　まず、測定に供するワイヤを試料ホルダーに直線状に固定する。次いで、ワイヤ軸に垂直な方向におけるワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下となるように測定面を決定する。測定面の長さは、測定面の幅の５倍となるように設定する。測定面の位置及び寸法を上記のとおり決定することにより、常温でのウェッジ接合に適用しても良好な接合性を実現するのに必要となる、表面におけるＣｕ濃度を精度良く測定することができる。また、ワイヤ軸方向に互いに１ｍｍ以上離間した複数箇所（ｎ≧３）の測定面について実施し、その平均値を採用することが好適である。
　上記の表面におけるＣｕ濃度は、後述の［オージェ電子分光法（ＡＥＳ）によるワイヤ表面の組成分析］欄に記載の条件にて測定した結果に基づくものである。
　－Ｃｕ芯材－
　本発明のワイヤは、Ｃｕ又はＣｕ合金からなる芯材、すなわちＣｕ芯材を含む。
　Ｃｕ芯材は、Ｃｕ又はＣｕ合金からなる限りにおいて特に限定されず、ボール接合用ボンディングワイヤとして知られている従来のＰｄ被覆Ｃｕワイヤを構成する公知のＣｕ芯材を用いてよい。
　Ｃｕ芯材は、例えば、後述の第１添加元素、第２添加元素から選択される１種以上のドーパントを含有してよい。これらドーパントの好適な含有量は後述のとおりである。
　好適な一実施形態において、Ｃｕ芯材は、Ｃｕと不可避不純物からなる。他の好適な一実施形態において、Ｃｕ芯材は、Ｃｕと、後述の第１添加元素、第２添加元素から選択される１種以上の元素と、不可避不純物とからなる。なお、Ｃｕ芯材についていう用語「不可避不純物」には、後述の貴金属被覆を構成する元素も包含される。
　Ｃｕは、他の金属中に含まれる場合、高温において拡散し易い性質を有する。Ｃｕ芯材と、該Ｃｕ芯材の表面に貴金属被覆とを有する本発明のワイヤにおいて、その製造時に熱処理を行うと、Ｃｕ芯材中のＣｕは貴金属被覆中を拡散し、ワイヤ表面に到達することができる。本発明のワイヤは、表面におけるＣｕ濃度が所定範囲にあることを特徴とするが、ワイヤ表面のＣｕは、斯かる拡散により表面に到達したＣｕであってよい。本発明のワイヤにおいて、表面のＣｕの状態は特に限定されず、一部が酸化していたり、貴金属被覆中の貴金属に一部固溶していたりしてもよい。
　本発明のワイヤにおいて、ワイヤ軸に垂直方向のＣｕ芯材断面（Ｃｕ芯材Ｃ断面）における平均結晶粒径は、常温でのウェッジ接合に適用した場合に（さらには接合時の荷重や超音波条件を低減させた場合であっても）一際良好な接合性を実現し得る観点から、好ましくは１．４μｍ以上、より好ましくは１．５μｍ以上、１．６μｍ以上、１．８μｍ以上又は２μｍ以上である。該平均結晶粒径の上限は、良好なループ形状安定性を実現する観点から、好ましくは３．２μｍ以下、より好ましくは３．１μｍ以下又は３μｍ以下である。したがって、好適な一実施形態において、Ｃｕ芯材Ｃ断面における平均結晶粒径は１．４～３．２μｍである。平均結晶粒径は、後方散乱電子線回折（ＥＢＳＤ：Ｅｌｅｃｔｒｏｎ　Ｂａｃｋ　Ｓｃａｔｔｅｒ　Ｄｉｆｆｒａｃｔｉｏｎ）法などの測定方法を用いて各結晶粒の面積を求め、各結晶粒の面積を円に見なしたときの直径の平均とする。Ｃｕ芯材Ｃ断面の平均結晶粒径は、後述の［Ｃｕ芯材Ｃ断面の平均結晶粒径の測定］に記載の方法により測定することができる。
　－貴金属被覆－
　本発明のワイヤは、Ｃｕ芯材の表面に設けられた貴金属を含有する被覆、すなわち貴金属被覆を含む。
　貴金属被覆が含有する貴金属は、本発明の効果を阻害しない限りにおいて特に限定されないが、樹脂封止により半導体装置を製造した場合であっても一際良好な接合信頼性を実現し得る観点から、パラジウム（Ｐｄ）又は金（Ａｕ）を含むことが好ましい。より好ましくはパラジウム（Ｐｄ）である。
　貴金属被覆に含まれる貴金属の合計を１００質量％としたとき、Ｐｄの含有量は、好ましくは５０質量％以上、より好ましくは６０質量％以上、７０質量％以上、８０質量％以上又は９０質量％以上である。該含有量の上限は特に限定されず、１００質量％であってもよいが、例えば、９９質量％以下、９８質量％以下、９７質量％以下などであってもよい。
　貴金属被覆は、例えば、後述の第１添加元素、第２添加元素から選択される１種以上のドーパントをさらに含有してよい。これらドーパントの好適な含有量は後述のとおりである。
　好適な一実施形態において、貴金属被覆は、貴金属と不可避不純物からなる。他の好適な一実施形態において、貴金属被覆は、貴金属と、後述の第１添加元素、第２添加元素から選択される１種以上の元素と、不可避不純物とからなる。なお、貴金属被覆についていう用語「不可避不純物」には、Ｃｕ芯材を構成する元素も包含される。
　樹脂封止により半導体装置を製造した場合であっても良好な接合信頼性を実現し得る観点、とりわけ高温高湿環境下においても良好な接合信頼性を実現する観点から、貴金属被覆における貴金属の最大濃度は、５０ａｔ％以上であることが好ましい。高温高湿環境下においても一際良好な接合信頼性を実現し得る観点から、該最大濃度は、より好ましくは６０ａｔ％以上、７０ａｔ％以上、７５ａｔ％以上又は８０ａｔ％以上である。該最大濃度の上限は特に限定されず、１００ａｔ％であってもよいが、例えば、９９．５ａｔ％以下、９９ａｔ％以下、９８ａｔ％以下などであってもよい。中でも、貴金属被覆が、斯かる最大濃度の好適条件を満たしつつ、その厚さ（算出方法は後述する。）が２０ｎｍ以上であると、高温高湿環境下においても一際優れた接合信頼性を実現し得るため好適である。貴金属被覆の厚さは、より好ましくは２５ｎｍ以上、さらに好ましくは３０ｎｍ以上、３５ｎｍ以上、４０ｎｍ以上、４５ｎｍ以上又は５０ｎｍ以上である。貴金属被覆の厚さに特に上限はないが、好ましくは０．５μｍ以下、より好ましくは０．４μｍ以下、０．３μｍ以下、０．２μｍ以下、０．１５μｍ以下又は０．１μｍ以下である。
　本発明において、貴金属被覆における貴金属の最大濃度は、ワイヤの表面からＡｒスパッタにより深さ方向に掘り下げていきながら、オージェ電子分光法（ＡＥＳ）により組成分析を行うことにより求めることができる。詳細には、１）Ａｒによるスパッタ処理、及び２）スパッタ処理後の表面組成分析を繰り返すことで深さ方向の濃度プロファイルを取得し、該濃度プロファイルから求めることができる。
　２）スパッタ処理後の表面組成分析は、表面におけるＣｕ濃度を求める際の、オージェ電子分光法（ＡＥＳ）による組成分析と同様の条件で実施することができる。すなわち、スパッタ処理後の表面についてオージェ電子分光法（ＡＥＳ）により組成分析を行うにあたり、測定面の位置及び寸法は、以下のとおり決定する。
　ワイヤ軸に垂直な方向におけるワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下となるように測定面を決定する。測定面の長さは、測定面の幅の５倍となるように設定する。測定面の位置及び寸法を上記のとおり決定することにより、樹脂封止により半導体装置を製造した場合であっても良好な接合信頼性を実現するのに好適な、貴金属被覆における貴金属の最大濃度を精度良く測定することができる。また、ワイヤ軸方向に互いに１ｍｍ以上離間した複数箇所（ｎ≧３）の測定面について実施し、その平均値を採用することが好適である。
　一実施形態に係る本発明のワイヤについて求められた、深さ方向の濃度プロファイルについて、その傾向を以下に説明する。ワイヤの表面から一定の深さ位置までは、Ｃｕ濃度が低下すると共に貴金属の濃度が上昇する傾向にある。さらに深さ方向に進むと、或る深さ位置（ｄ）を境にして、貴金属の濃度が低下すると共にＣｕ濃度が上昇する傾向にある。このような濃度プロファイルにおいて、貴金属の濃度の増減に着目して、貴金属の濃度が最大となる位置（上記の実施形態においては、深さ位置ｄ）から、貴金属の最大濃度を求めることができる。貴金属被覆が複数の貴金属を含む場合、「貴金属の最大濃度」を求めるにあたっては、これら複数の貴金属の合計濃度の増減に着目すればよい。例えば、貴金属被覆がＰｄを単独で含む場合、Ｐｄの濃度の増減に着目すればよく、貴金属被覆がＰｄとＡｕを組み合わせて含む場合、ＰｄとＡｕの合計濃度の増減に着目すればよい。
　上記の、貴金属被覆における貴金属の最大濃度の好適範囲は、後述の［オージェ電子分光法（ＡＥＳ）による深さ方向の濃度プロファイルの取得］欄に記載の条件にて測定した結果に基づくものである。
　本発明のワイヤにおいて、貴金属被覆は、Ｐｄに加えて金（Ａｕ）を含んでもよい。貴金属被覆が、Ｐｄに加えてＡｕをさらに含むことにより、常温でのウェッジ接合に適用した場合に一際良好な接合性を呈すると共に、接合信頼性にも一際優れるボンディングワイヤを実現することができる。
　貴金属被覆がＡｕを含む場合、貴金属被覆に含まれる貴金属の合計を１００質量％としたとき、Ａｕの含有量は、好ましくは０．５質量％以上、より好ましくは１質量％以上、１．５質量％以上又は２質量％以上である。該含有量の上限は、過度のコストアップを避ける観点から、例えば１０質量％以下、７質量％以下、５質量％以下、又は３質量％以下などとし得る。
　貴金属被覆が、Ｐｄに加えてＡｕをさらに含む場合、本発明の効果をより享受し得る観点から、貴金属被覆におけるＡｕの最大濃度を示す位置がＰｄの最大濃度を示す位置よりも表面側にあることが好適である。この場合、上記で得た深さ方向の濃度プロファイルにおいて、Ａｕの濃度の増減とＰｄの濃度の増減に別個独立に着目すればよい。
　本発明のワイヤにおいて、Ｃｕ芯材と貴金属被覆との境界は、貴金属の合計濃度を基準に判定する。貴金属の合計濃度が２０ａｔ％の位置を境界とし、貴金属の合計濃度が２０ａｔ％以上の領域を貴金属被覆、２０ａｔ％未満の領域をＣｕ芯材と判定する。なお、貴金属の合計濃度が２０ａｔ％未満でも、上記判定による貴金属被覆よりワイヤ表面側に存在する相（層）については貴金属被覆と判定する。
　貴金属被覆の厚さは、オージェ電子分光法（ＡＥＳ）により得られた深さ方向の濃度プロファイルにおいて、ワイヤ軸からワイヤ表面に向けて濃度プロファイルを確認し、貴金属の合計濃度がはじめて２０ａｔ％に達した深さ位置からワイヤ表面位置までの距離として求めることができる。先述の貴金属被覆の厚さは、オージェ電子分光法（ＡＥＳ）により得られた深さ方向の濃度プロファイルに基づき、深さの単位をＳｉＯ２換算した結果に基づくものである。
　本発明のワイヤは、Ｎｉ、Ｚｎ、Ｒｈ、Ｉｎ、Ｉｒ及びＰｔからなる群から選択される１種以上の元素（「第１添加元素」）をさらに含有してよい。ワイヤ全体に対する第１添加元素の濃度は総計で０．１質量％以上であることが好ましい。これにより、高温用途に適用した場合であってもガルバニック腐食の進行をさらに抑制することができ、接合信頼性に格別優れるボンディングワイヤを実現することができる。ワイヤ全体に対する第１添加元素の濃度は総計で０．３質量％以上であることがより好ましく、０．５質量％以上であることがさらに好ましい。第１添加元素の総計濃度の上限は、ワイヤの硬質化を抑え常温でのウェッジ接合に適用した場合に良好な接合性を実現し易い観点から、１．５質量％以下であることが好ましく、１．４質量％以下、１．３質量％以下又は１．２質量％以下であることがより好ましい。したがって好適な一実施形態において、本発明のワイヤは、第１添加元素を含み、ワイヤ全体に対する第１添加元素の濃度が総計で０．１～１．５質量％である。あるいはまた、第１添加元素について、ワイヤ全体に対するＮｉの濃度は、０．１質量％未満であってもよく、例えば、０．０９質量％以下、０．０８質量％以下などであってもよい。
　本発明のワイヤは、Ｐ、Ｂ、Ｂｅ、Ｆｅ、Ｍｇ、Ｔｉ、Ｚｎ、Ａｇ、Ｓｉからなる群から選択される１種以上の元素（以下、「第２添加元素」ともいう。）をさらに含有してよい。ワイヤ全体に対する第２添加元素の濃度は総計で０．１質量ｐｐｍ以上であることが好ましい。これにより、ループ形状安定性にさらに優れるワイヤを実現することができる。ワイヤ全体に対する第２添加元素の濃度は総計で１質量ｐｐｍ以上であることがより好ましく、２質量ｐｐｍ以上、３質量ｐｐｍ以上、５質量ｐｐｍ以上、８質量ｐｐｍ以上、１０質量ｐｐｍ以上、２０質量ｐｐｍ以上、３０質量ｐｐｍ以上又は４０質量％以上であることがさらに好ましく、５０質量ｐｐｍ以上又は５５質量ｐｐｍ以上であることがさらにより好ましい。第２添加元素の総計濃度の上限は、ワイヤの硬質化を抑え常温でのウェッジ接合に適用した場合に良好な接合性を実現し易い観点から、２００質量ｐｐｍ以下であることが好ましく、１９０質量ｐｐｍ以下、１８０質量ｐｐｍ以下、１７０質量ｐｐｍ以下、１６０質量ｐｐｍ以下又は１５０質量ｐｐｍ以下であることがさらに好ましい。
　ワイヤ中の第１添加元素や第２添加元素の含有量は、後述の［元素含有量の測定］に記載の方法により測定することができる。
　本発明のワイヤの直径は、特に限定されず具体的な目的に応じて適宜決定してよいが、好ましくは１５μｍ以上、１８μｍ以上又は２０μｍ以上などとし得る。該直径の上限は、特に限定されず、例えば２００μｍ以下、１５０μｍ以下又は１００μｍ以下などとし得る。
　＜ワイヤの製造方法＞
　本発明の半導体装置用ボンディングワイヤの製造方法の一例について説明する。
　まず、高純度（４Ｎ～６Ｎ；９９．９９～９９．９９９９質量％以上）の原料銅を連続鋳造により大径（直径約３～６ｍｍ）に加工し、インゴットを得る。
　上述の第１添加元素や第２添加元素等のドーパントを添加する場合、その添加方法としては、例えば、Ｃｕ芯材中に含有させる方法、貴金属被覆中に含有させる方法、Ｃｕ芯材の表面に被着させる方法、及び、貴金属被覆の表面に被着させる方法が挙げられ、これらの方法を複数組み合わせてもよい。何れの添加方法を採用しても、本発明の効果を発揮することができる。ドーパントをＣｕ芯材中に含有させる方法では、ドーパントを必要な濃度含有した銅合金を原料として用い、Ｃｕ芯材を製造すればよい。原材料であるＣｕにドーパントを添加して斯かる銅合金を得る場合、Ｃｕに、高純度のドーパント成分を直接添加してもよく、ドーパント成分を１％程度含有する母合金を利用してもよい。ドーパントを貴金属被覆中に含有させる方法では、貴金属被覆を形成する際の貴金属めっき浴（湿式めっきの場合）やターゲット材（乾式めっきの場合）中にドーパントを含有させればよい。Ｃｕ芯材の表面に被着させる方法や貴金属被覆の表面に被着させる方法では、Ｃｕ芯材の表面あるいは貴金属被覆の表面を被着面として、（１）水溶液の塗布⇒乾燥⇒熱処理、（２）めっき法（湿式）、（３）蒸着法（乾式）、から選択される１以上の被着処理を実施すればよい。
　大径のインゴットを鍛造、圧延、伸線を行って直径約０．９～１．２ｍｍのＣｕ又はＣｕ合金からなるワイヤ（以下、「中間ワイヤ」ともいう。）を作製する。
　Ｃｕ芯材の表面に貴金属被覆を形成する手法としては、電解めっき、無電解めっき、蒸着法等が利用できるが、膜厚を安定的に制御できる電解めっきを利用するのが工業的には好ましい。例えば、ＰｄとＡｕを組み合わせて含む貴金属被覆を形成する場合、中間ワイヤ表面にＰｄ被覆を形成した後、該Ｐｄ被覆の表面にＡｕ被覆を形成してよい。Ｐｄ被覆、Ａｕ被覆はまた、大径のインゴットの段階で被着することとしてもよく、あるいは、中間ワイヤを伸線してさらに細線化した後（例えば最終的なＣｕ芯材の直径まで伸線した後）に、該Ｃｕ芯材表面にＰｄ被覆、Ａｕ被覆を形成してよい。
　伸線加工は、ダイヤモンドコーティングされたダイスを複数個セットできる連続伸線装置を用いて実施することができる。必要に応じて、伸線加工の途中段階で熱処理を施してもよい。熱処理によりＰｄとＡｕを互いに拡散させて、ＡｕとＰｄの合金を含む貴金属被覆を形成してもよい。その方法としては一定の炉内温度で電気炉中、ワイヤを一定の速度の下で連続的に掃引することで合金化を促す方法が、確実に合金の組成と厚みを制御できるので好ましい。
　伸線加工の後、表面改質熱処理を行う。表面改質熱処理は、表面におけるＣｕ濃度が所定範囲にあるボンディングワイヤを実現し易い観点から、高温で長時間実施することが好適である。貴金属被覆の厚さや所望する表面Ｃｕ濃度等にもよるが、表面改質熱処理の温度は、銅の融点をＴｍ（Ｋ）としたとき、０．６Ｔｍ～０．８Ｔｍの範囲にて決定することが好適である。銅の融点Ｔｍは１３５８Ｋ（＝１０８５℃）であることから、表面改質熱処理の温度は、好ましくは５４０℃～８２０℃の範囲である。また、表面改質熱処理の時間は、好ましくは５秒間以上、より好ましくは７秒間以上又は１０秒間以上である。該熱処理時間の上限は、例えば、２０秒間以下とし得る。
　表面改質熱処理の雰囲気ガスとしては、水素含有不活性ガスが好適であり、例えば、水素含有ヘリウムガス、水素含有窒素ガス、水素含有アルゴンガスが挙げられる。水素含有不活性ガス中の水素濃度は、例えば１～２０％の範囲としてよい。好適な一実施形態において、表面改質熱処理の雰囲気ガスは、フォーミングガス（５％Ｈ２－Ｎ２）である。あるいはまた、熱処理時の温度・時間の厳密な管理の下、雰囲気ガスとして、窒素ガス、アルゴンガス等の不活性ガスを用いてよい。
　本発明のワイヤは、半導体装置の製造において、半導体素子上の第１電極と、リードフレーム又は回路基板上の第２電極とを接続するために用いることができる。半導体素子上の第１電極との第１接続（１ｓｔ接合）と、リードフレーム又は回路基板上の第２電極との第２接続（２ｎｄ接合）とは、何れもウェッジ接合であってよい。貴金属被覆を有すると共に表面のＣｕ濃度が所定範囲にある本発明のワイヤは、常温でウェッジ接合する場合でも良好な接合性を実現し得る。したがって、本発明のワイヤは、ウェッジ接合用（詳細にはウェッジ－ウェッジ接合用）として好適に使用することができ、常温ウェッジ接合用（詳細には常温ウェッジ－ウェッジ接合用）としても好適に使用することができる。
　［半導体装置の製造方法］
　本発明の半導体装置用ボンディングワイヤを用いて、半導体素子上の電極と、リードフレームや回路基板上の電極とを接続することによって、半導体装置を製造することができる。
　一実施形態において、本発明の半導体装置の製造方法（以下、単に「本発明の方法」ともいう。）は、半導体素子上の第１電極と、リードフレーム又は回路基板上の第２電極とを、本発明のワイヤにより接続する工程を含み、第１電極と本発明のワイヤとの第１接続と、第２電極と本発明のワイヤとの第２接続の両方をウェッジ接合により実施することを特徴とする。
　ウェッジ接合では、ボールを形成せずに、ワイヤ部を超音波、圧力を加えることにより電極上に圧着接合する。貴金属被覆を有すると共に表面のＣｕ濃度が所定範囲にある本発明のワイヤは、常温でウェッジ接合する場合でも良好な接合性を実現することができる。したがって好適な一実施形態において、本発明の方法では、第１接続と第２接続を常温下で実施する。
　貴金属被覆を有すると共に表面のＣｕ濃度が所定範囲にある本発明のワイヤは、樹脂封止により半導体装置を製造する場合であっても、良好な接合信頼性を実現することができる。したがって好適な一実施形態において、本発明の方法は、ウェッジ接合の後に樹脂封止する工程をさらに含む。樹脂封止に用いる樹脂としては、半導体装置の製造にあたって樹脂封止に使用し得る公知の熱硬化性樹脂組成物（例えばエポキシ樹脂組成物）を用いてよい。本発明のワイヤを用いることにより、熱硬化性樹脂組成物の仕様によらず、良好な接合信頼性を有利に実現することができる。
　［半導体装置］
　本発明の半導体装置用ボンディングワイヤを用いて、半導体素子上の電極と、リードフレームや回路基板上の電極とを接続することによって、半導体装置を製造することができる。
　一実施形態において、本発明の半導体装置は、回路基板、半導体素子、及び回路基板と半導体素子とを導通させるためのボンディングワイヤを含み、該ボンディングワイヤが本発明のワイヤであることを特徴とする。
　本発明の半導体装置において、回路基板及び半導体素子は特に限定されず、半導体装置を構成するために使用し得る公知の回路基板及び半導体素子を用いてよい。あるいはまた、回路基板に代えてリードフレームを用いてもよい。例えば、特開２００２－２４６５４２号公報に記載される半導体装置のように、リードフレームと、該リードフレームに実装された半導体素子とを含む半導体装置の構成としてよい。
　半導体装置としては、電気製品（例えば、コンピューター、携帯電話、デジタルカメラ、テレビ、エアコン、太陽光発電システム等）及び乗物（例えば、自動二輪車、自動車、電車、船舶及び航空機等）等に供される各種半導体装置が挙げられる。
　以下、本発明について、実施例を示して具体的に説明する。ただし、本発明は、以下に示す実施例に限定されるものではない。
　（サンプル）
　まずサンプルの作製方法について説明する。Ｃｕ芯材の原材料となるＣｕは、純度が９９．９９質量％以上（４Ｎ）で残部が不可避不純物から構成されるものを用いた。また、第１添加元素や第２添加元素を添加する場合、これらは純度が９９質量％以上で残部が不可避不純物から構成されるもの、あるいはＣｕにこれら添加元素が高濃度で配合された母合金を用いた。
　芯材のＣｕ合金は、カーボンるつぼに原料を装填し、高周波炉を用いて、真空中もしくはＮ２やＡｒガス等の不活性雰囲気で１０９０～１５００℃まで加熱して溶解した後、連続鋳造により大径に加工し、次いで伸線加工により最終線径まで細線化することで製造した。得られたφ３～６ｍｍの銅または銅合金の芯材に対して、引抜加工を行ってφ０．９～１．２ｍｍまで加工した後、ダイスを用いて連続的に伸線加工等を行うことによって、さらにワイヤを細径化した。伸線加工を行う場合には、市販の潤滑液を用い、伸線速度は２０～１５０ｍ／分とした。ワイヤ表面の酸化膜を除去するために、塩酸による酸洗処理を行った後、芯材のＣｕ合金の表面全体を覆うようにＰｄ被覆を形成した。さらに、一部のワイヤ（実施例Ｎｏ．１～６、９～１４、１７～２８、比較例Ｎｏ．１～４）はＰｄ被覆の上にＡｕ被覆を形成した。Ｐｄ被覆、Ａｕ被覆の形成には電解めっき法を用いた。Ｐｄめっき液、Ａｕめっき液は市販のめっき液を用いた。
　その後、さらに伸線加工等を行い、最終線径であるφ３５μｍまで加工した。必要に応じて、伸線加工の途中において、３００～７００℃、２～１５秒間の熱処理を０～２回行った。最終線径まで加工後、表面改質熱処理を行った。表面改質熱処理の熱処理温度は５００～７５０℃とし、ワイヤの送り速度は３０～１００ｍ／分、熱処理時間は２～１５秒とした。中間熱処理および表面改質熱処理の熱処理方法はワイヤを連続的に掃引しながら行い、Ａｒガスを流しながら行った。
　（試験・評価方法）
　以下、試験・評価方法について説明する。
　［オージェ電子分光法（ＡＥＳ）によるワイヤ表面の組成分析］
　ワイヤ表面におけるＣｕ濃度は、ワイヤ表面を測定面として、以下のとおりオージェ電子分光法（ＡＥＳ）により測定して求めた。
　まず測定に供するボンディングワイヤを試料ホルダーに直線状に固定した。次いで、ワイヤ長手軸に垂直な方向におけるワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下となるように測定面を決定した。測定面の長さは測定面の幅の５倍とした。そして、ＡＥＳ装置（アルバック・ファイ製ＰＨＩ－７００）を用いて、加速電圧１０ｋＶの条件にてワイヤ表面の組成分析を行い、表面Ｃｕ濃度（ａｔ％）を求めた。
　なお、ＡＥＳによる組成分析は、ワイヤ長手方向に互いに１ｍｍ以上離間した３箇所の測定面について実施し、その平均値を採用した。表面におけるＣｕ濃度を求めるにあたり、炭素（Ｃ）、硫黄（Ｓ）、酸素（Ｏ）、窒素（Ｎ）等ガス成分、非金属元素等は考慮しなかった。
　［オージェ電子分光法（ＡＥＳ）による深さ方向の濃度プロファイルの取得］
　ワイヤの深さ方向の濃度プロファイルは、ＡＥＳによるワイヤ表面の組成分析の後、ワイヤの表面からＡｒスパッタにより深さ方向に掘り下げていきながら、ＡＥＳにより組成分析を行うことにより求めた。
　詳細には、ＡＥＳによるワイヤ表面の組成分析の後、１）Ａｒによるスパッタ処理、及び２）スパッタ処理後の表面組成分析を繰り返すことで深さ方向の濃度プロファイルを取得した。１）のスパッタ処理は、Ａｒ＋イオン、加速電圧１ｋＶ、にて行った。また、２）の表面組成分析において、測定面の寸法やＡＥＳによる組成分析の条件は、上記［オージェ電子分光法（ＡＥＳ）によるワイヤ表面の組成分析］欄で説明したものと同じとした。
　なお、深さ方向の濃度プロファイルの取得は、ワイヤ長手方向に互いに１ｍｍ以上離間した３箇所の測定面について実施した。
　－貴金属被覆における貴金属の最大濃度－
　取得した深さ方向の濃度プロファイルにおいて、貴金属の濃度の増減に着目して、貴金属の濃度が最大となる位置から、貴金属の最大濃度を求めた。３箇所の測定面について取得した数値の平均値を貴金属の最大濃度として採用した。
　なお、貴金属被覆がＰｄとＡｕを含む実施例及び比較例のワイヤに関して、Ａｕの最大濃度を示す位置がＰｄの最大濃度を示す位置よりも表面側にあることを確認した。
　－貴金属被覆の厚さ－
　取得した深さ方向の濃度プロファイルにおいて、ワイヤ軸からワイヤ表面に向けて濃度プロファイルを確認し、貴金属の合計濃度がはじめて２０ａｔ％に達した深さ位置からワイヤ表面位置までの距離として貴金属被覆の厚さを求めた。３箇所の測定面について取得した数値の平均値を貴金属被覆の厚さとして採用した。
　なお、貴金属被覆の厚さは、深さ方向の濃度プロファイルに基づき、深さの単位をＳｉＯ２換算して求めた。
　［元素含有量の測定］
　ワイヤ中の第１添加元素、第２添加元素の含有量は、ＩＣＰ発光分光分析装置、ＩＣＰ質量分析装置を用いて、ワイヤ全体に含まれる元素の濃度として分析した。分析装置として、ＩＣＰ－ＯＥＳ（（株）日立ハイテクサイエンス製「ＰＳ３５２０ＵＶＤＤＩＩ」）又はＩＣＰ－ＭＳ（アジレント・テクノロジーズ（株）製「Ａｇｉｌｅｎｔ　７７００ｘ　ＩＣＰ－ＭＳ」）を用いた。
　［Ｃｕ芯材Ｃ断面の平均結晶粒径の測定］
　Ｃｕ芯材Ｃ断面の平均結晶粒径の測定は、後方散乱電子線回折（ＥＢＳＤ：Ｅｌｅｃｔｒｏｎ　Ｂａｃｋ　ｓｃａｔｔｅｒ　Ｄｉｆｆｒａｃｔｉｏｎ）法（測定装置　オックスフォード・インストゥルメンツ（株）製ＥＢＳＤ分析システム「ＡＺｔｅｃ　ＨＫＬ］）を用いて測定した。詳細には、Ｃｕ芯材Ｃ断面の全体について各結晶粒の面積を求め、各結晶粒の面積を円の面積に換算してその直径の平均を算出し、これを平均結晶粒径として採用した。なお、各結晶粒の面積は、隣り合う測定点間の方位差が１５度以上の位置を粒界と定義して求めた。
　［常温ウェッジ接合性］
　シリコン基板上に厚さ３．０μｍのＡｌ－０．５質量％Ｃｕ合金を成膜して設けた電極に、常温（２５℃）でウェッジ接合を行った。無作為に選択した２０箇所の接合部について、接合強度をシェア試験により測定し、その平均値をウェッジ接合部の接合強度として採用した。そして、以下の基準に従って、評価した。
　評価基準：
　◎：１００ｇｆ以上
　○：７５ｇｆ以上１００ｇｆ未満
　△：５０ｇｆ以上７５ｇｆ未満
　×：５０ｇｆ未満
　［接合信頼性］
　接合信頼性は、高温高湿試験（ＨＡＳＴ；Highly　Accelerated　Temperature　and　Humidity　Stress　Test）及び高温放置試験（ＨＴＳＬ：High　Temperature　Storage　Life　Test）の双方により評価した。
　－ＨＡＳＴ－
　シリコン基板上に厚さ３．０μｍのＡｌ－０．５質量％Ｃｕ合金を成膜して設けた電極に常温でウェッジ接合したサンプルを、市販の熱硬化性エポキシ樹脂により封止し、接合信頼性試験用のサンプルを作製した。作製した接合信頼性評価用のサンプルを、不飽和型プレッシャークッカー試験機を使用し、温度１３０℃、相対湿度８５％の高温高湿環境に暴露し、７Ｖのバイアスをかけた。ウェッジ接合部の接合寿命は、４８時間毎にウェッジ接合部のシェア試験を実施し、シェア強度の値が初期に得られたシェア強度の１／２となる時間とした。シェア強度の値は無作為に選択したウェッジ接合部の５０箇所の測定値の平均値を用いた。シェア試験は、酸処理によって樹脂を除去して、ウェッジ接合部を露出させてから行った。そして、以下の基準に従って、評価した。
　評価基準：
　◎：接合寿命３８４時間以上
　○：接合寿命２４０時間以上３８４時間未満
　×：接合寿命２４０時間未満
　－ＨＴＳＬ－
　上記と同様の手順で作製した接合信頼性評価用のサンプルを、高温恒温機を使用し、温度１７５℃の環境に暴露した。ウェッジ接合部の接合寿命は、５００時間毎にウェッジ接合部のプル試験を実施し、プル強度の値が初期に得られたプル強度の１／２となる時間とした。プル強度の値は無作為に選択したウェッジ接合部の５０箇所の測定値の平均値を用いた。高温放置試験後のプル試験は、酸処理によって樹脂を除去して、ウェッジ接合部を露出させてから行った。そして、以下の基準に従って、評価した。
　評価基準：
　◎：接合寿命２０００時間以上
　○：接合寿命１０００時間以上２０００時間未満
　×：接合寿命１０００時間未満
　［ループ形状安定性］
　ループ形状安定性（ループプロファイルの再現性）は、ループ長が２ｍｍ、ループ高さが３００μｍとなるように台形ループを１００本接続し、最大ループ高さの標準偏差より評価した。高さ測定には光学顕微鏡を使用し、以下の基準に従って評価した。
　評価基準：
　◎：３σが２０μｍ未満
　○：３σが２０μｍ以上２５μｍ未満
　×：３σが２５μｍ以上
　実施例及び比較例の評価結果を表１に示す。
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
　実施例Ｎｏ．１～３７はいずれも、Ｃｕ芯材の表面に設けられた貴金属被覆を有し、表面におけるＣｕ濃度が本発明範囲内にあり、常温でのウェッジ接合において良好な接合性を呈し、また、接合信頼性にも優れることを確認した。
　加えて、第１添加元素を総計で０．１質量％以上含有する実施例Ｎｏ．２～８、１０～１５、１７～２３、３１、３２、３５及び３７（特に第１添加元素の含有量が０．５質量％以上である実施例Ｎｏ．２、４～６、８、１０～１２、１４、１５、１７～２１、２３、３１、３２、３５及び３７）は、高温環境におけるガルバニック腐食の進行をさらに抑制することができ、接合信頼性（ＨＴＳＬ）に格別優れることを確認した。
　第２添加元素を総計で０．１質量ｐｐｍ以上含有する実施例Ｎｏ．１～２４、３３～３５及び３７（特に第２添加元素の含有量が５０質量ｐｐｍ以上である実施例Ｎｏ．３、４、６～８、１０、１４、１７、１９、３３～３５及び３７）は、格別優れたループ形状安定性を実現することを確認した。
　他方、比較例Ｎｏ．１～４は、Ｃｕ芯材の表面に設けられた貴金属被覆を有するものの、表面におけるＣｕ濃度が本発明範囲外であり、常温でのウェッジ接合に適用した場合に接合不良に帰着したり、接合信頼性も不良となったりすることを確認した。 

Claims (18)

  1. 　Ｃｕ又はＣｕ合金からなる芯材（以下、「Ｃｕ芯材」という。）、及び
    　該Ｃｕ芯材の表面に設けられた貴金属を含有する被覆（以下、「貴金属被覆」という。）、
    を有する半導体装置用ボンディングワイヤであって、
    　該ワイヤの表面におけるＣｕ濃度が３０～８０ａｔ％である、半導体装置用ボンディングワイヤ。
  2. 　表面におけるＣｕ濃度が、下記＜条件＞にてオージェ電子分光法（ＡＥＳ：Auger　Electron　Spectroscopy）により測定される、請求項１に記載のボンディングワイヤ。
    　＜条件＞ワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下、測定面の長さが測定面の幅の５倍である
  3. 　貴金属被覆がＰｄを含む、請求項１又は２に記載のボンディングワイヤ。
  4. 　貴金属被覆がさらにＡｕを含む、請求項３に記載のボンディングワイヤ。
  5. 　貴金属被覆における貴金属の最大濃度が５０ａｔ％以上である、請求項１～４の何れか１項に記載のボンディングワイヤ。
  6. 　貴金属被覆におけるＡｕの最大濃度を示す位置がＰｄの最大濃度を示す位置よりも表面側にある、請求項４又は５に記載のボンディングワイヤ。
  7. 　貴金属被覆における貴金属の最大濃度が、ワイヤの表面からＡｒスパッタにより深さ方向に掘り下げていきながら、下記＜条件＞にてオージェ電子分光法（ＡＥＳ）により測定して得られる深さ方向の濃度プロファイルから求められる、請求項５又は６に記載のボンディングワイヤ。
    　＜条件＞ワイヤの幅の中心が測定面の幅の中心となるように位置決めし、かつ、測定面の幅がワイヤ直径の１０％以上１５％以下、測定面の長さが測定面の幅の５倍である
  8. 　Ｃｕ芯材が、Ｃｕと不可避不純物からなる、請求項１～７の何れか１項に記載のボンディングワイヤ。
  9. 　貴金属被覆が、貴金属と不可避不純物からなる、請求項１～８の何れか１項に記載のボンディングワイヤ。
  10. 　Ｎｉ、Ｚｎ、Ｒｈ、Ｉｎ、Ｉｒ及びＰｔからなる群から選択される１種以上の元素（以下、「第１添加元素」という。）を含み、ワイヤ全体に対する第１添加元素の濃度が総計で０．１～１．５質量％である、請求項１～７の何れか１項に記載のボンディングワイヤ。
  11. 　Ｐ、Ｂ、Ｂｅ、Ｆｅ、Ｍｇ、Ｔｉ、Ｚｎ、Ａｇ及びＳｉからなる群から選択される１種以上の元素（以下、「第２添加元素」という。）を含み、ワイヤ全体に対する第２添加元素の濃度が総計で０．１～２００質量ｐｐｍである、請求項１～７、１０の何れか１項に記載のボンディングワイヤ。
  12. 　Ｃｕ芯材が、Ｃｕと、第１添加元素及び第２添加元素から選択される１種以上の元素と、不可避不純物からなる、請求項１０又は１１に記載のボンディングワイヤ。
  13. 　貴金属被覆が、貴金属と、第１添加元素及び第２添加元素から選択される１種以上の元素と、不可避不純物からなる、請求項１０～１２の何れか１項に記載のボンディングワイヤ。
  14. 　ワイヤ軸に垂直方向のＣｕ芯材断面における平均結晶粒径が１．４～３．２μｍである、請求項１～１３の何れか１項に記載のボンディングワイヤ。
  15. 　ウェッジ－ウェッジ接合用である、請求項１～１４の何れか１項に記載のボンディングワイヤ。
  16. 　半導体素子上の第１電極と、リードフレーム又は回路基板上の第２電極とを、請求項１～１５の何れか１項に記載のボンディングワイヤにより接続する工程を含み、
    　第１電極とボンディングワイヤとの第１接続と、第２電極とボンディングワイヤとの第２接続の両方をウェッジ接合により実施する、半導体装置の製造方法。
  17. 　第１接続と第２接続を常温下で実施する、請求項１６に記載の方法。
  18. 　請求項１～１５の何れか１項に記載のボンディングワイヤを含む半導体装置。
PCT/JP2021/011217 2020-03-25 2021-03-18 半導体装置用ボンディングワイヤ WO2021193378A1 (ja)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CN202180022853.3A CN115362537A (zh) 2020-03-25 2021-03-18 半导体装置用接合线
KR1020227031913A KR20220153593A (ko) 2020-03-25 2021-03-18 반도체 장치용 본딩 와이어
JP2022510054A JPWO2021193378A1 (ja) 2020-03-25 2021-03-18
EP21776531.2A EP4130310A1 (en) 2020-03-25 2021-03-18 Bonding wire for semiconductor device
US17/913,365 US20230148306A1 (en) 2020-03-25 2021-03-18 Bonding wire for semiconductor devices

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020055028 2020-03-25
JP2020-055028 2020-03-25

Publications (1)

Publication Number Publication Date
WO2021193378A1 true WO2021193378A1 (ja) 2021-09-30

Family

ID=77891749

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/011217 WO2021193378A1 (ja) 2020-03-25 2021-03-18 半導体装置用ボンディングワイヤ

Country Status (7)

Country Link
US (1) US20230148306A1 (ja)
EP (1) EP4130310A1 (ja)
JP (1) JPWO2021193378A1 (ja)
KR (1) KR20220153593A (ja)
CN (1) CN115362537A (ja)
TW (1) TW202146672A (ja)
WO (1) WO2021193378A1 (ja)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022270051A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270076A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270077A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
US11721660B2 (en) 2021-06-25 2023-08-08 Nippon Micrometal Corporation Bonding wire for semiconductor devices
US11929343B2 (en) 2021-06-25 2024-03-12 Nippon Micrometal Corporation Bonding wire for semiconductor devices

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002246542A (ja) 2001-02-15 2002-08-30 Matsushita Electric Ind Co Ltd パワーモジュール及びその製造方法
JP2005167020A (ja) 2003-12-03 2005-06-23 Sumitomo Electric Ind Ltd ボンディングワイヤーおよびそれを使用した集積回路デバイス
JP2007012776A (ja) * 2005-06-29 2007-01-18 Nippon Steel Materials Co Ltd 半導体装置用ボンディングワイヤ
JP2010212697A (ja) * 2007-07-24 2010-09-24 Nippon Steel Materials Co Ltd 半導体装置用ボンディングワイヤ
JP2011249463A (ja) * 2010-05-25 2011-12-08 Tatsuta Electric Wire & Cable Co Ltd ボンディングワイヤ
JP2016511529A (ja) 2012-11-22 2016-04-14 ヘレウス ドイチェラント ゲーエムベーハー ウント カンパニー カーゲー ボンディング用途のアルミニウム合金ワイヤ
JP2019033275A (ja) * 2015-05-26 2019-02-28 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2019130570A1 (ja) * 2017-12-28 2019-07-04 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002246542A (ja) 2001-02-15 2002-08-30 Matsushita Electric Ind Co Ltd パワーモジュール及びその製造方法
JP2005167020A (ja) 2003-12-03 2005-06-23 Sumitomo Electric Ind Ltd ボンディングワイヤーおよびそれを使用した集積回路デバイス
JP2007012776A (ja) * 2005-06-29 2007-01-18 Nippon Steel Materials Co Ltd 半導体装置用ボンディングワイヤ
JP2010212697A (ja) * 2007-07-24 2010-09-24 Nippon Steel Materials Co Ltd 半導体装置用ボンディングワイヤ
JP2011249463A (ja) * 2010-05-25 2011-12-08 Tatsuta Electric Wire & Cable Co Ltd ボンディングワイヤ
JP2016511529A (ja) 2012-11-22 2016-04-14 ヘレウス ドイチェラント ゲーエムベーハー ウント カンパニー カーゲー ボンディング用途のアルミニウム合金ワイヤ
JP2019033275A (ja) * 2015-05-26 2019-02-28 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2019130570A1 (ja) * 2017-12-28 2019-07-04 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022270051A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270076A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270050A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270077A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270049A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
WO2022270075A1 (ja) * 2021-06-25 2022-12-29 日鉄マイクロメタル株式会社 半導体装置用ボンディングワイヤ
US11721660B2 (en) 2021-06-25 2023-08-08 Nippon Micrometal Corporation Bonding wire for semiconductor devices
US11929343B2 (en) 2021-06-25 2024-03-12 Nippon Micrometal Corporation Bonding wire for semiconductor devices

Also Published As

Publication number Publication date
JPWO2021193378A1 (ja) 2021-09-30
TW202146672A (zh) 2021-12-16
KR20220153593A (ko) 2022-11-18
CN115362537A (zh) 2022-11-18
US20230148306A1 (en) 2023-05-11
EP4130310A1 (en) 2023-02-08

Similar Documents

Publication Publication Date Title
WO2021193378A1 (ja) 半導体装置用ボンディングワイヤ
JP5964534B1 (ja) 半導体装置用ボンディングワイヤ
TWI427719B (zh) The joint structure of the joining wire and its forming method
JP2019033275A (ja) 半導体装置用ボンディングワイヤ
JP2020031238A (ja) 半導体装置用ボンディングワイヤ
JP2020010067A (ja) 半導体装置用ボンディングワイヤ
TWI761637B (zh) 鈀被覆銅接合線及其製造方法
JP7217393B1 (ja) 半導体装置用ボンディングワイヤ
JP7157280B1 (ja) 半導体装置用ボンディングワイヤ
JP5937770B1 (ja) 半導体装置用ボンディングワイヤ
WO2022270076A1 (ja) 半導体装置用ボンディングワイヤ
WO2022270440A1 (ja) 半導体装置用ボンディングワイヤ
WO2022270077A1 (ja) 半導体装置用ボンディングワイヤ
WO2023249037A1 (ja) 半導体装置用ボンディングワイヤ
WO2023248491A1 (ja) 半導体装置用ボンディングワイヤ
EP4361299A1 (en) Bonding wire for semiconductor device
JP2024002933A (ja) 半導体装置用ボンディングワイヤ

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21776531

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022510054

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2021776531

Country of ref document: EP

Effective date: 20221025