WO2015053128A1 - Bonding-wire copper strand, and manufacturing method for bonding-wire copper strand - Google Patents

Bonding-wire copper strand, and manufacturing method for bonding-wire copper strand Download PDF

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Publication number
WO2015053128A1
WO2015053128A1 PCT/JP2014/075999 JP2014075999W WO2015053128A1 WO 2015053128 A1 WO2015053128 A1 WO 2015053128A1 JP 2014075999 W JP2014075999 W JP 2014075999W WO 2015053128 A1 WO2015053128 A1 WO 2015053128A1
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Prior art keywords
wire
bonding
copper
strand
purity
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PCT/JP2014/075999
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French (fr)
Japanese (ja)
Inventor
訓 熊谷
雨 谷
雄次 佐藤
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三菱マテリアル株式会社
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Priority to CN201480004297.7A priority Critical patent/CN104904000B/en
Priority to SG11201602116YA priority patent/SG11201602116YA/en
Publication of WO2015053128A1 publication Critical patent/WO2015053128A1/en
Priority to PH12016500617A priority patent/PH12016500617A1/en

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    • 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
    • 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
    • H01L24/43—Manufacturing methods
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
    • 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
    • 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
    • H01L2224/43—Manufacturing methods
    • H01L2224/432—Mechanical processes
    • H01L2224/4321—Pulling
    • 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
    • H01L2224/43—Manufacturing methods
    • H01L2224/438—Post-treatment of the connector
    • H01L2224/43848—Thermal treatments, e.g. annealing, controlled cooling
    • 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
    • H01L2224/4501—Shape
    • H01L2224/45012—Cross-sectional shape
    • H01L2224/45015—Cross-sectional shape being circular
    • 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
    • H01L2224/45144—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
    • H01L2224/45001—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

Definitions

  • the present invention relates to a copper wire for bonding wire for forming a bonding wire.
  • the semiconductor element and the lead are connected by a bonding wire.
  • a bonding wire As a bonding wire, Au wire is mainly used from the viewpoints of drawability and conductivity.
  • Au is expensive, a bonding wire made of a Cu wire is provided as a bonding wire that replaces the Au wire.
  • a bonding wire made of Cu wire is obtained by drawing a cast material having a wire diameter of 4 mm to 8 mm to 0.5 mm to obtain a copper wire for bonding wire, and further drawing the copper wire for bonding wire. It is manufactured by processing to a wire diameter of 30 ⁇ m to 50 ⁇ m.
  • Patent Documents 1 and 2 propose bonding wires made of Cu wire of high-purity copper (so-called 6NCu) having a purity of 99.9999% by mass or more. Since this bonding wire has high purity, its strength is low, the loop shape of the wire is easily formed, and the reliability is improved. Moreover, since there is high purity, there are few inclusions and it can suppress that a disconnection arises at the time of wire drawing.
  • the copper wire for bonding wire for forming the bonding wire is required to have a workability that does not break during the wire drawing even if the wire is thinned.
  • the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a copper wire for a bonding wire that has good workability and hardly breaks even if it is thinned.
  • the inventors of the present invention have made a copper wire for bonding wire drawn to produce a bonding wire, and the copper wire for bonding wire is perpendicular to the wire drawing direction. It was found that by controlling the area ratio of the (001) plane in a simple cross section to a specific range, the workability of the copper wire for bonding wire can be improved and the disconnection during wire drawing can be suppressed.
  • the present invention has been completed based on the above findings, and the gist thereof is as follows.
  • the copper wire for bonding wire according to the first aspect of the present invention is a copper wire for bonding wire for forming a bonding wire, and is made of high-purity copper having a purity of 99.9999% by mass or more.
  • the wire diameter is 0.5 mm or more and 3.5 mm or less, and the area ratio of the (001) plane is 15% or more and 30% or less in a cross section perpendicular to the drawing direction.
  • the manufacturing method of the copper strand for bonding wires which concerns on the 2nd aspect of this invention is the heat
  • a cold-drawing process a cold-drawing process in which the produced wire is cold-drawn within a range of 80% to 99.6%, and the drawn wire
  • the hot working is a hot extrusion process in which the area reduction rate is 99% or more and 99.95% or less at a temperature of 700 ° C. or more and 900 ° C. or less. May be.
  • the area ratio of the (001) plane is 15% or more and 30% or less in the cross section perpendicular to the drawing direction. It is possible to improve, and the occurrence of disconnection during wire drawing can be suppressed.
  • the area ratio of the (001) plane is less than 15%, other orientations including the (111) plane increase, the strength decreases, and the wire breaks during wire drawing. Is likely to occur.
  • the area ratio of the (001) plane is more than 30% in a cross section perpendicular to the wire drawing direction, the elongation is lowered, and breakage is likely to occur during the wire drawing.
  • the area ratio of the (001) plane is set in the above range. Further, since the copper wire for bonding wire is made of high-purity copper having a purity of 99.9999% by mass or more, the strength of the bonding wire using the copper wire for bonding wire is sufficiently lowered, and the reliability of the bonding wire is improved. Can be improved. Moreover, since high purity copper with a purity of 99.9999% by mass or more has few inclusions, it is possible to suppress the occurrence of disconnection due to the inclusions during wire drawing. According to the method for manufacturing a copper wire for bonding wire according to the second aspect of the present invention, the area ratio of the (001) plane in the cross section perpendicular to the drawing direction of the copper wire for bonding wire is 15% or more and 30%. It can be as follows.
  • the copper wire for bonding wire according to the present embodiment is used as a wire when manufacturing a bonding wire having a wire diameter of 80 ⁇ m or less, preferably 5 ⁇ m or more and 50 ⁇ m or less.
  • the copper wire for bonding wire has a wire diameter of 0.5 mm to 3.5 mm.
  • the copper wire for bonding wires is made of high-purity copper (6NCu) having a purity of 99.9999% by mass or more.
  • the copper wire for bonding wire has an area ratio of (001) plane of 15% to 30% in a cross section perpendicular to the drawing direction.
  • the cross section perpendicular to the drawing direction is a cross section that includes the central axis of the copper wire for bonding wire and is orthogonal to the central axis.
  • the area ratio of the region in which the ⁇ 001> direction is oriented is the area ratio of the (001) plane.
  • the area ratio of the (001) plane when the area ratio of the (001) plane is less than 15% in the cross section perpendicular to the wire drawing direction, the strength decreases because other orientations including the (111) plane increase, and the wire breaks during wire drawing. Is likely to occur. Further, when the area ratio of the (001) plane is more than 30% in a cross section perpendicular to the wire drawing direction, the elongation is lowered, and breakage is likely to occur during the wire drawing. For these reasons, the area ratio of the (001) plane in the cross section perpendicular to the drawing direction is set in the above range.
  • the area ratio of the (001) plane is preferably 18% or more and 28% or less, but is not limited thereto.
  • the area ratio of the (001) plane of the cross section perpendicular to the drawing direction can be measured by an electron back scattering diffraction pattern (EBSD method).
  • EBSD method is obtained by connecting an EBSD detector to an SEM (scanning electron microscope), analyzing the orientation of the diffraction image (EBSD) of each crystal generated when the sample surface is irradiated with a focused electron beam, and analyzing it.
  • SEM scanning electron microscope
  • the crystal orientation of the material is measured from the obtained orientation data and position information of the measurement point.
  • the method for manufacturing a copper wire for bonding wire includes a hot working step S1, a wire drawing step S2, and a heat treatment step S3. Details of each step will be described below.
  • a billet (ingot) having a diameter of 250 mm and a length of 700 mm made of high-purity copper having a purity of 99.9999% by mass or more is prepared. Then, the billet is heated to a temperature range of 700 ° C. to 900 ° C. and hot-extruded in a range of 99% to 99.95% of the area reduction rate to produce a strand having a wire diameter of 6 mm to 20 mm. To do.
  • this hot working step S1 in order to destroy the cast structure of the billet (ingot) and make a fine and uniform hot worked structure as compared with the cast structure, in the above temperature range and area reduction rate. Hot extrusion is performed. In this embodiment, heating was performed at 800 ° C., and hot extrusion was performed under the condition of a surface reduction rate of 99.9% to produce a strand having a wire diameter of 8 mm.
  • Wire drawing process S2 The wire produced in the hot working step S1 described above is drawn (cold drawing) within a range of the area reduction rate of 80% or more and 99.6% or less, and the wire diameter is 0.5 mm or more and 3 Process to 5mm or less.
  • the wire drawing may be performed in one pass, but is preferably performed in a plurality of passes.
  • the hot work structure (crystal grains) formed in the hot work process S1 extends in the wire drawing direction to form a fibrous metal structure.
  • processing is performed from 8 mm to 1 mm in diameter (wire diameter) in 15 passes, and the area reduction rate is 98%.
  • a peeling wire drawing process may be performed.
  • Heat treatment step S3 The element wire drawn in the wire drawing step S2 is subjected to heat treatment within a range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes.
  • the heat treatment step S3 is performed in a batch annealing furnace having a reducing atmosphere.
  • a part of the metal structure made fibrous in the wire drawing step S2 is recrystallized, and a metal structure in which a fibrous metal structure and an equiaxed recrystallized structure coexist. It has become.
  • the wire is heat-treated in a reducing gas atmosphere by a batch-type annealing furnace at 220 ° C. for 60 minutes.
  • the copper wire for bonding wire according to the present embodiment is manufactured.
  • this copper wire for bonding wires into a bonding wire it is set as a 20-micrometer bonding wire, for example by drawing at a surface reduction rate of 99.96%.
  • the area ratio of the (001) plane is 15% or more and 30% or less in the cross section perpendicular to the drawing direction. The workability can be improved and the occurrence of disconnection at the time of wire drawing can be suppressed.
  • the copper wire for bonding wire is made of high-purity copper having a purity of 99.9999% by mass or more, the strength of the bonding wire using the copper wire for bonding wire is sufficiently lowered, and the reliability of the bonding wire is improved. Can be improved. Moreover, since high purity copper with a purity of 99.9999% by mass or more has few inclusions, it is possible to suppress the occurrence of disconnection due to the inclusions during wire drawing.
  • the manufacturing method of the copper wire for bonding wires which concerns on this embodiment is the hot working process S1 which hot-processes the ingot which consists of high purity copper, and produces a strand, and a surface area reduction rate of a strand
  • a heat treatment step S3 for performing the heat treatment inside. For this reason, the copper wire for bonding wires in which the area ratio of the (001) plane is 15% or more and 30% or less in a cross section perpendicular to the wire drawing direction can be manufactured.
  • the wire drawing step S2 When the wire drawing step S2 is performed within the range of the area reduction rate of 80% or more and 99.6% or less with respect to the strand produced in the hot working step S1, the crystal grains become fibrous in the drawing direction.
  • An elongated metal structure is formed, and the (001) plane increases in a cross section perpendicular to the drawing direction.
  • the elongation may be small (it is difficult to elongate) and may break.
  • the area reduction rate in the wire drawing step S2 is preferably 89% or more and 99.5% or less, but is not limited thereto.
  • the wire drawn in the wire drawing step S2 is subjected to a heat treatment within a range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes by a batch annealing furnace. I do. For this reason, the area ratio of the (001) plane in the cross section perpendicular to the wire drawing direction can be reliably controlled to 15% or more and 30% or less.
  • the heating temperature in the heat treatment step S3 is preferably 210 ° C. or higher and 250 ° C. or lower, but is not limited thereto.
  • the heating time is less than 30 minutes, sufficient recrystallized grains are not generated, and it becomes difficult to control the area ratio of the (001) plane to 30% or less.
  • the heating time exceeds 300 minutes, recrystallization proceeds too much, and it becomes difficult to control the area ratio of the (001) plane to 15% or more.
  • the heating temperature is preferably 60 minutes or more and 180 minutes or less, but is not limited thereto.
  • the heat treatment conditions of the heat treatment step are set in the range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes.
  • the area ratio of the (001) plane can be stably controlled within the above range by performing the heat treatment under the above heating conditions using a batch annealing furnace.
  • the shape and size of the ingot which consists of high purity copper of purity 99.9999 mass% or more, and it is not limited to this embodiment.
  • Comparative Example 1 a copper wire for bonding wire was manufactured without performing heat treatment after wire drawing. That is, a copper wire for bonding wire of Comparative Example 1 was manufactured in the same manner as the above-described example of the present invention except that the heat treatment after the wire drawing was not performed.
  • Comparative Example 2 First, an ingot made of high-purity copper having a purity of 99.9999% or more was prepared. Using this ingot as a raw material, a strand having a diameter of 8 mm was cast. Next, a wire having a diameter of 1 mm was drawn to a diameter of 1 mm, including cold peel drawing. In this wire drawing, the area reduction rate was 98%, and the number of passes was 15. Thus, the copper wire for bonding wires of Comparative Example 2 was produced. In addition, also in the comparative example 2, the heat processing after a wire drawing process are not performed.
  • EBSD measurement was performed on a cross section perpendicular to the drawing direction, and the area ratio of the (001) plane was measured.
  • the EBSD measurement procedure will be described below.
  • a cross section perpendicular to the wire drawing direction of the copper wire for bonding wire was mechanically polished using water-resistant abrasive paper and diamond abrasive grains, and then finish-polished using a colloidal silica solution.
  • an EBSD measuring device HITACHI S4300-SEM, EDAX / TSL OIM Data Collection
  • analysis software EDAX / TSL OIM Data Analysis ver.5.2
  • an electron beam is irradiated to each measurement point within the measurement range of the sample surface (cross section perpendicular to the drawing direction of the copper wire for bonding wire), and the electron beam is scanned two-dimensionally on the sample surface. Then, orientation analysis by backscattered electron diffraction was performed. In addition, the measurement point interval was 1.80 ⁇ m, and EBSD measurement was performed on an area of 600 ⁇ m ⁇ 940 ⁇ m. In the cross section of the copper wire for bonding wire measured by EBSD, a crystal plane with a deviation angle of 15 ° or less (crystal plane with an angle of (001) plane within 15 °) with respect to the (001) plane. Considering it as the (001) plane, the area ratio of the (001) plane in the measurement region was evaluated.
  • the manufactured copper wire for bonding wire was further drawn to a diameter of 5 ⁇ m.
  • wire drawing was performed from a diameter of 1 mm (1000 ⁇ m) to 100 ⁇ m, and wire drawing was further carried out to 100 ⁇ m to 50 ⁇ m, 50 ⁇ m to 25 ⁇ m, 25 ⁇ m to 10 ⁇ m, and 10 ⁇ m to 5 ⁇ m.
  • this wire drawing process was implemented so that the wire of 100 m of full length might be obtained in the step processed to 5 micrometers.
  • Comparative Example 1 since wire breakage occurred frequently in the wire drawing process, the production of the wire (drawing process) was stopped halfway. The measurement results are shown in Table 1.
  • Examples 1 to 5 of the present invention had good workability because the number of wire breaks was small even when wire drawing was performed from 100 ⁇ m to 5 ⁇ m.
  • Examples 1 to 5 of the present invention are copper wires for bonding wires that are less likely to be broken even if they are thinned.
  • Comparative Example 1 since the heat treatment was not performed after the wire was drawn to a diameter of 1 mm, the area ratio of the (001) plane was over 30%, and the number of disconnections was increased compared to the inventive example.
  • Comparative Example 2 an element wire having a diameter of 8 mm is cast, and the element wire is drawn to a diameter of 1 mm. The area reduction rate of the drawing process to a diameter of 1 mm is insufficient as compared with the example of the present invention. For this reason, the area ratio of the (001) plane was less than 15%, and the number of disconnections increased compared to the inventive example.
  • the workability is good and disconnection hardly occurs even if the wire is thinned, so that the bonding wire can be thinned.

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Abstract

　This bonding-wire copper strand is used to form a bonding wire. Said copper strand is formed from highly pure copper having a purity of at least 99.9999 mass%, and has a strand diameter between 0.5 mm to 3.5 mm inclusive. The surface area ratio of the (001) plane is between 15% and 30% inclusive at a cross section perpendicular to the drawing direction.

Description

ボンディングワイヤ用銅素線、及びボンディングワイヤ用銅素線の製造方法Copper wire for bonding wire and method for manufacturing copper wire for bonding wire
　本発明は、ボンディングワイヤを形成するためのボンディングワイヤ用銅素線に関する。
　本願は、２０１３年１０月１０日に、日本に出願された特願２０１３－２１３１１４号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a copper wire for bonding wire for forming a bonding wire.
This application claims priority based on Japanese Patent Application No. 2013-213114 filed in Japan on October 10, 2013, the contents of which are incorporated herein by reference.
　一般に、半導体素子を搭載した半導体装置においては、半導体素子とリードとが、ボンディングワイヤによって接続されている。従来、ボンディングワイヤとしては、伸線性及び導電性等の観点から主にＡｕ線が使用されている。しかしながら、Ａｕは高価であることから、Ａｕ線を代替するボンディングワイヤとして、Ｃｕ線からなるボンディングワイヤが提供されている。 Generally, in a semiconductor device equipped with a semiconductor element, the semiconductor element and the lead are connected by a bonding wire. Conventionally, as a bonding wire, Au wire is mainly used from the viewpoints of drawability and conductivity. However, since Au is expensive, a bonding wire made of a Cu wire is provided as a bonding wire that replaces the Au wire.
　Ｃｕ線からなるボンディングワイヤは、例えば、線径４ｍｍ～８ｍｍの鋳造材を０．５ｍｍまで伸線加工して、ボンディングワイヤ用銅素線とした後に、このボンディングワイヤ用銅素線をさらに伸線加工して、線径３０μｍから５０μｍに加工することによって製造される。例えば特許文献１、２には、純度が９９．９９９９質量％以上の高純度銅（いわゆる６ＮＣｕ）のＣｕ線からなるボンディングワイヤが提案されている。このボンディングワイヤは純度が高いため強度が低く、ワイヤのループ形状等が形成され易く、信頼性が向上する。また、純度が高いため介在物が少なく、伸線加工時において断線が生じることを抑制できる。 For example, a bonding wire made of Cu wire is obtained by drawing a cast material having a wire diameter of 4 mm to 8 mm to 0.5 mm to obtain a copper wire for bonding wire, and further drawing the copper wire for bonding wire. It is manufactured by processing to a wire diameter of 30 μm to 50 μm. For example, Patent Documents 1 and 2 propose bonding wires made of Cu wire of high-purity copper (so-called 6NCu) having a purity of 99.9999% by mass or more. Since this bonding wire has high purity, its strength is low, the loop shape of the wire is easily formed, and the reliability is improved. Moreover, since there is high purity, there are few inclusions and it can suppress that a disconnection arises at the time of wire drawing.
特開昭６２－１１１４５５号公報Japanese Unexamined Patent Publication No. Sho 62-111455 特開平０４－２４７６３０号公報Japanese Patent Laid-Open No. 04-247630
　ところで、近年、半導体装置の小型化や低コスト化のために、ボンディングワイヤの細線化が求められており、今後、ボンディングワイヤの線径は、例えば１０μｍ以下まで細くなることが想定される。したがって、ボンディングワイヤを形成するためのボンディングワイヤ用銅素線には、細線化しても伸線加工時において断線することのない加工性が必要とされている。 Incidentally, in recent years, thinning of bonding wires has been demanded in order to reduce the size and cost of semiconductor devices, and it is expected that the wire diameter of bonding wires will be reduced to, for example, 10 μm or less in the future. Therefore, the copper wire for bonding wire for forming the bonding wire is required to have a workability that does not break during the wire drawing even if the wire is thinned.
　しかしながら、特許文献１、２に示されたボンディングワイヤの製造時において、ボンディングワイヤ用銅素線を伸線加工して例えば線径１０μｍまで加工すると、素線の伸びが不十分となり、高い頻度で素線の断線が生じてしまう。このようにボンディングワイヤ用銅素線を伸線加工する際に断線が生じると、生産性が著しく低下してしまう問題が生じる。 However, when the bonding wires shown in Patent Documents 1 and 2 are manufactured, if the copper wire for bonding wires is drawn and processed to, for example, a wire diameter of 10 μm, the elongation of the wires becomes insufficient, and frequently occurs. Wire breakage will occur. Thus, when a wire breakage occurs when the copper wire for bonding wires is drawn, there arises a problem that the productivity is significantly reduced.
　この発明は、前述した事情に鑑みてなされたものであって、加工性が良好で、細線化しても断線が生じ難いボンディングワイヤ用銅素線を提供することを目的とする。 The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a copper wire for a bonding wire that has good workability and hardly breaks even if it is thinned.
　本発明者らは、上述した課題を解決すべく検討した結果、ボンディングワイヤ用銅素線を伸線加工してボンディングワイヤを製造する際に、ボンディングワイヤ用銅素線において、伸線方向と垂直な断面における（００１）面の面積率を特定の範囲に制御することにより、ボンディングワイヤ用銅素線の加工性を向上し、伸線加工時における断線を抑制できるとの知見を得た。
　本発明は、上記の知見に基づき完成させたものであって、その要旨は以下の通りである。 As a result of studying to solve the above-described problems, the inventors of the present invention have made a copper wire for bonding wire drawn to produce a bonding wire, and the copper wire for bonding wire is perpendicular to the wire drawing direction. It was found that by controlling the area ratio of the (001) plane in a simple cross section to a specific range, the workability of the copper wire for bonding wire can be improved and the disconnection during wire drawing can be suppressed.
The present invention has been completed based on the above findings, and the gist thereof is as follows.
　すなわち、本発明の第一の態様に係るボンディングワイヤ用銅素線は、ボンディングワイヤを形成するためのボンディングワイヤ用銅素線であって、純度が９９．９９９９質量％以上の高純度銅からなり、線径が０．５ｍｍ以上３．５ｍｍ以下であり、伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下であることを特徴としている。
　また、本発明の第二の態様に係るボンディングワイヤ用銅素線の製造方法は、純度９９．９９９９質量％以上の高純度銅からなる鋳塊を熱間加工して素線を製出する熱間加工工程と、製出された前記素線を減面率８０％以上９９．６％以下の範囲内で冷間伸線加工をする伸線加工工程と、伸線加工された前記素線に対して２００℃以上２６０℃以下、３０分以上３００分以下の範囲内で加熱処理を行う加熱処理工程と、を備える。
　第二の態様に係るボンディング銅素線の製造方法において、前記熱間加工が、７００℃以上９００℃以下の温度で減面率９９％以上９９．９５％以下まで行われる熱間押出し加工であっても良い。
　また、前記加熱処理工程においてバッチ式焼鈍炉を用いて前記素線を加熱しても良い。 That is, the copper wire for bonding wire according to the first aspect of the present invention is a copper wire for bonding wire for forming a bonding wire, and is made of high-purity copper having a purity of 99.9999% by mass or more. The wire diameter is 0.5 mm or more and 3.5 mm or less, and the area ratio of the (001) plane is 15% or more and 30% or less in a cross section perpendicular to the drawing direction.
Moreover, the manufacturing method of the copper strand for bonding wires which concerns on the 2nd aspect of this invention is the heat | fever which produces a strand by hot-working the ingot which consists of high purity copper more than purity 99.9999 mass%. A cold-drawing process, a cold-drawing process in which the produced wire is cold-drawn within a range of 80% to 99.6%, and the drawn wire And a heat treatment step of performing a heat treatment within a range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes.
In the method for manufacturing a bonded copper wire according to the second aspect, the hot working is a hot extrusion process in which the area reduction rate is 99% or more and 99.95% or less at a temperature of 700 ° C. or more and 900 ° C. or less. May be.
Moreover, you may heat the said strand using a batch-type annealing furnace in the said heat processing process.
　本発明の第一の態様に係るボンディングワイヤ用銅素線によれば、伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下とされているので、加工性を向上することができ、伸線時における断線の発生を抑制可能となる。
　伸線方向と垂直な断面において、（００１）面の面積率が１５％未満の場合、（１１１）面をはじめとする他の方位が増加してしまい、強度が低下し、伸線加工時に破断が生じ易くなる。また、伸線方向と垂直な断面において（００１）面の面積率が３０％超の場合、伸びが低下し、伸線加工時に破断が生じ易くなる。したがって、（００１）面の面積率は、上述の範囲に設定されている。
　さらに、ボンディングワイヤ用銅素線が、純度９９．９９９９質量％以上の高純度銅からなるので、このボンディングワイヤ用銅素線を用いたボンディングワイヤの強度を十分に低くし、ボンディングワイヤの信頼性を向上できる。また、純度が９９．９９９９質量％以上の高純度銅は、介在物が少ないので、伸線加工時において介在物に起因する断線の発生を抑制できる。
　本発明の第二の態様に係るボンディングワイヤ用銅素線の製造方法によれば、ボンディングワイヤ用銅素線の伸線方向と垂直な断面において（００１）面の面積率を１５％以上３０％以下とすることができる。 In the copper wire for bonding wire according to the first aspect of the present invention, the area ratio of the (001) plane is 15% or more and 30% or less in the cross section perpendicular to the drawing direction. It is possible to improve, and the occurrence of disconnection during wire drawing can be suppressed.
In the cross section perpendicular to the wire drawing direction, when the area ratio of the (001) plane is less than 15%, other orientations including the (111) plane increase, the strength decreases, and the wire breaks during wire drawing. Is likely to occur. Further, when the area ratio of the (001) plane is more than 30% in a cross section perpendicular to the wire drawing direction, the elongation is lowered, and breakage is likely to occur during the wire drawing. Therefore, the area ratio of the (001) plane is set in the above range.
Further, since the copper wire for bonding wire is made of high-purity copper having a purity of 99.9999% by mass or more, the strength of the bonding wire using the copper wire for bonding wire is sufficiently lowered, and the reliability of the bonding wire is improved. Can be improved. Moreover, since high purity copper with a purity of 99.9999% by mass or more has few inclusions, it is possible to suppress the occurrence of disconnection due to the inclusions during wire drawing.
According to the method for manufacturing a copper wire for bonding wire according to the second aspect of the present invention, the area ratio of the (001) plane in the cross section perpendicular to the drawing direction of the copper wire for bonding wire is 15% or more and 30%. It can be as follows.
　本発明によれば、加工性が良好で、細線化しても断線が生じ難いボンディングワイヤ用銅素線を提供することができる。 According to the present invention, it is possible to provide a copper wire for bonding wire that has good workability and hardly breaks even if it is thinned.
本発明の実施形態に係るボンディングワイヤ用銅素線の製造方法のフロー図である。It is a flowchart of the manufacturing method of the copper strand for bonding wires which concerns on embodiment of this invention.
　以下に、本発明の実施形態に係るボンディングワイヤ用銅素線、及びボンディングワイヤ用銅素線の製造方法について説明する。 Hereinafter, a copper wire for bonding wire and a method for manufacturing the copper wire for bonding wire according to the embodiment of the present invention will be described.
　本実施形態に係るボンディングワイヤ用銅素線は、線径８０μｍ以下、望ましくは線径５μｍ以上５０μｍ以下のボンディングワイヤを製造する際の素線として使用されるものである。また、ボンディングワイヤ用銅素線は、線径が０．５ｍｍ以上３．５ｍｍ以下とされている。 The copper wire for bonding wire according to the present embodiment is used as a wire when manufacturing a bonding wire having a wire diameter of 80 μm or less, preferably 5 μm or more and 50 μm or less. The copper wire for bonding wire has a wire diameter of 0.5 mm to 3.5 mm.
　ボンディングワイヤ用銅素線は、純度が９９．９９９９質量％以上の高純度銅（６ＮＣｕ）からなる。
　そして、このボンディングワイヤ用銅素線は、伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下とされている。本実施形態において、伸線方向と垂直な断面とは、ボンディングワイヤ用銅素線の中心軸を含み、この中心軸と直交する断面である。また、本実施形態では、伸線方向と垂直な断面に配向される、（００１）面に対してズレ角１５°以内の結晶面の合計の面積率、すなわち、伸線方向に対し１５°以内に＜００１＞方向が配向された領域の面積率を（００１）面の面積率としている。 The copper wire for bonding wires is made of high-purity copper (6NCu) having a purity of 99.9999% by mass or more.
The copper wire for bonding wire has an area ratio of (001) plane of 15% to 30% in a cross section perpendicular to the drawing direction. In the present embodiment, the cross section perpendicular to the drawing direction is a cross section that includes the central axis of the copper wire for bonding wire and is orthogonal to the central axis. In the present embodiment, the total area ratio of crystal planes with a deviation angle of 15 ° or less with respect to the (001) plane oriented in a cross section perpendicular to the wire drawing direction, that is, within 15 ° with respect to the wire drawing direction. The area ratio of the region in which the <001> direction is oriented is the area ratio of the (001) plane.
　ここで、伸線方向と垂直な断面において（００１）面の面積率が１５％未満の場合、（１１１）面をはじめとする他の方位が増加するので強度が低下し、伸線加工時に破断が生じ易くなる。また、伸線方向と垂直な断面において（００１）面の面積率が３０％超の場合、伸びが低下し、伸線加工時に破断が生じ易くなる。
　このような理由により、伸線方向と垂直な断面において（００１）面の面積率は、上述の範囲に設定されている。（００１）面の面積率は１８％以上２８％以下とすることが好ましいが、これに限定されない。 Here, when the area ratio of the (001) plane is less than 15% in the cross section perpendicular to the wire drawing direction, the strength decreases because other orientations including the (111) plane increase, and the wire breaks during wire drawing. Is likely to occur. Further, when the area ratio of the (001) plane is more than 30% in a cross section perpendicular to the wire drawing direction, the elongation is lowered, and breakage is likely to occur during the wire drawing.
For these reasons, the area ratio of the (001) plane in the cross section perpendicular to the drawing direction is set in the above range. The area ratio of the (001) plane is preferably 18% or more and 28% or less, but is not limited thereto.
　なお、伸線方向と垂直な断面の（００１）面の面積率については、電子後方散乱回折像（Ｅｌｅｃｔｒｏｎ　Ｂａｃｋ　Ｓｃａｔｔｅｒ　Ｄｉｆｆｒａｃｔｉｏｎ　Ｐａｔｔｅｒｎｓ）法（ＥＢＳＤ法）によって測定することができる。このＥＢＳＤ法は、ＳＥＭ（走査電子顕微鏡）にＥＢＳＤ検出器を接続し、収束電子ビームを試料表面に照射したときに発生する個々の結晶の回折像（ＥＢＳＤ）の方位を解析し、解析により得られた方位データと測定点の位置情報から材料の結晶方位を測定する方法である。 In addition, the area ratio of the (001) plane of the cross section perpendicular to the drawing direction can be measured by an electron back scattering diffraction pattern (EBSD method). This EBSD method is obtained by connecting an EBSD detector to an SEM (scanning electron microscope), analyzing the orientation of the diffraction image (EBSD) of each crystal generated when the sample surface is irradiated with a focused electron beam, and analyzing it. In this method, the crystal orientation of the material is measured from the obtained orientation data and position information of the measurement point.
　次に、本実施形態に係るボンディングワイヤ用銅素線の製造方法について説明する。ボンディングワイヤ用銅素線の製造方法は、例えば図１に示すように、熱間加工工程Ｓ１と、伸線加工工程Ｓ２と、加熱処理工程Ｓ３とを備えている。以下に、各工程の詳細を説明する。 Next, a method for manufacturing a copper wire for bonding wire according to this embodiment will be described. As shown in FIG. 1, for example, the method for manufacturing a copper wire for bonding wire includes a hot working step S1, a wire drawing step S2, and a heat treatment step S3. Details of each step will be described below.
（熱間加工工程Ｓ１）
　まず、純度が９９．９９９９質量％以上の高純度銅からなる直径２５０ｍｍ、長さ７００ｍｍのビレット（鋳塊）を用意する。
　そして、このビレットを７００℃以上９００℃以下の温度範囲に加熱し、減面率９９％以上９９．９５％以下の範囲で熱間押出し加工し、線径６ｍｍ以上２０ｍｍ以下の素線を製出する。この熱間加工工程Ｓ１においては、ビレット（鋳塊）が有する鋳造組織を破壊し、鋳造組織に比較して微細で均一な熱間加工組織にするために、上述の温度範囲及び減面率で熱間押出し加工を行っている。
　本実施形態においては、８００℃に加熱し、減面率９９．９％の条件で熱間押出し加工を行い、線径８ｍｍの素線を製出した。 (Hot processing step S1)
First, a billet (ingot) having a diameter of 250 mm and a length of 700 mm made of high-purity copper having a purity of 99.9999% by mass or more is prepared.
Then, the billet is heated to a temperature range of 700 ° C. to 900 ° C. and hot-extruded in a range of 99% to 99.95% of the area reduction rate to produce a strand having a wire diameter of 6 mm to 20 mm. To do. In this hot working step S1, in order to destroy the cast structure of the billet (ingot) and make a fine and uniform hot worked structure as compared with the cast structure, in the above temperature range and area reduction rate. Hot extrusion is performed.
In this embodiment, heating was performed at 800 ° C., and hot extrusion was performed under the condition of a surface reduction rate of 99.9% to produce a strand having a wire diameter of 8 mm.
（伸線加工工程Ｓ２）
　上述の熱間加工工程Ｓ１において製出された素線を、減面率８０％以上９９．６％以下の範囲内で伸線加工（冷間伸線加工）し、線径０．５ｍｍ以上３．５ｍｍ以下に加工する。ここで、伸線加工は、１パスで行われても良いが、複数パスに分けて行われることが好ましい。この伸線加工工程Ｓ２においては、熱間加工工程Ｓ１で形成された熱間加工組織（結晶粒）が伸線加工方向に伸長し、繊維状の金属組織となる。
　本実施形態においては、１５パスで直径（線径）８ｍｍから１ｍｍまで加工を行っており、減面率は９８％とされている。
　なお、伸線加工工程Ｓ２においては、皮剥ぎ伸線加工が行われても良い。 (Wire drawing process S2)
The wire produced in the hot working step S1 described above is drawn (cold drawing) within a range of the area reduction rate of 80% or more and 99.6% or less, and the wire diameter is 0.5 mm or more and 3 Process to 5mm or less. Here, the wire drawing may be performed in one pass, but is preferably performed in a plurality of passes. In this wire drawing process S2, the hot work structure (crystal grains) formed in the hot work process S1 extends in the wire drawing direction to form a fibrous metal structure.
In this embodiment, processing is performed from 8 mm to 1 mm in diameter (wire diameter) in 15 passes, and the area reduction rate is 98%.
In the wire drawing step S2, a peeling wire drawing process may be performed.
（加熱処理工程Ｓ３）
　上述の伸線加工工程Ｓ２において伸線された素線に対して２００℃以上２６０℃以下、３０分以上３００分以下の範囲内で加熱処理を行う。ここで、加熱処理工程Ｓ３は、還元雰囲気とされたバッチ式焼鈍炉で行われる。この加熱処理工程Ｓ３においては、伸線加工工程Ｓ２で繊維状とされた金属組織のうちの一部が再結晶し、繊維状の金属組織と等軸の再結晶組織とが混在した金属組織となっている。
　本実施形態においては、バッチ式焼鈍炉によって、２２０℃で６０分の条件で、還元ガス雰囲気中で素線の加熱処理が行われている。 (Heat treatment step S3)
The element wire drawn in the wire drawing step S2 is subjected to heat treatment within a range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes. Here, the heat treatment step S3 is performed in a batch annealing furnace having a reducing atmosphere. In this heat treatment step S3, a part of the metal structure made fibrous in the wire drawing step S2 is recrystallized, and a metal structure in which a fibrous metal structure and an equiaxed recrystallized structure coexist. It has become.
In the present embodiment, the wire is heat-treated in a reducing gas atmosphere by a batch-type annealing furnace at 220 ° C. for 60 minutes.
　以上のようにして本実施形態に係るボンディングワイヤ用銅素線が製造される。
　なお、このボンディングワイヤ用銅素線をボンディングワイヤに加工する場合、例えば減面率９９．９６％で伸線加工することにより、２０μｍのボンディングワイヤとされる。 As described above, the copper wire for bonding wire according to the present embodiment is manufactured.
In addition, when processing this copper wire for bonding wires into a bonding wire, it is set as a 20-micrometer bonding wire, for example by drawing at a surface reduction rate of 99.96%.
　以上のような構成とされた本実施形態に係るボンディングワイヤ用銅素線によれば、伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下とされているので、加工性を向上させることができ、伸線時における断線の発生を抑制可能となる。 According to the copper wire for bonding wire according to the present embodiment configured as described above, the area ratio of the (001) plane is 15% or more and 30% or less in the cross section perpendicular to the drawing direction. The workability can be improved and the occurrence of disconnection at the time of wire drawing can be suppressed.
　さらに、ボンディングワイヤ用銅素線が、純度９９．９９９９質量％以上の高純度銅からなるので、このボンディングワイヤ用銅素線を用いたボンディングワイヤの強度を十分に低くし、ボンディングワイヤの信頼性を向上できる。また、純度が９９．９９９９質量％以上の高純度銅は、介在物が少ないので、伸線加工時において介在物に起因する断線の発生を抑制できる。 Further, since the copper wire for bonding wire is made of high-purity copper having a purity of 99.9999% by mass or more, the strength of the bonding wire using the copper wire for bonding wire is sufficiently lowered, and the reliability of the bonding wire is improved. Can be improved. Moreover, since high purity copper with a purity of 99.9999% by mass or more has few inclusions, it is possible to suppress the occurrence of disconnection due to the inclusions during wire drawing.
　また、本実施形態に係るボンディングワイヤ用銅素線の製造方法は、高純度銅からなる鋳塊を熱間加工して素線を製出する熱間加工工程Ｓ１と、素線を減面率８０％以上９９．６％以下の範囲内で伸線加工をする伸線加工工程Ｓ２と、この伸線加工された素線に対して２００℃以上２６０℃以下、３０分以上３００分以下の範囲内で加熱処理を行う加熱処理工程Ｓ３と、を備える。このため、伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下とされたボンディングワイヤ用銅素線を製造することができる。 Moreover, the manufacturing method of the copper wire for bonding wires which concerns on this embodiment is the hot working process S1 which hot-processes the ingot which consists of high purity copper, and produces a strand, and a surface area reduction rate of a strand A drawing process S2 for drawing in the range of 80% to 99.6%, and a range of 200 ° C. to 260 ° C., 30 minutes to 300 minutes with respect to the drawn wire. A heat treatment step S3 for performing the heat treatment inside. For this reason, the copper wire for bonding wires in which the area ratio of the (001) plane is 15% or more and 30% or less in a cross section perpendicular to the wire drawing direction can be manufactured.
　熱間加工工程Ｓ１で製出された素線に対して、減面率８０％以上９９．６％以下の範囲内で伸線加工工程Ｓ２を行うと、結晶粒が伸線方向に繊維状に伸びた金属組織となり、伸線方向と垂直な断面において（００１）面が増加する。この繊維状に伸びた金属組織は、さらに伸線加工を行うと、伸びが少ない（伸び難い）ために破断が生じてしまうことがある。そこで、上述した条件で加熱処理工程Ｓ３を行うことによって、繊維状に伸びた金属組織の一部を再結晶させて（００１）面の面積率を所定の範囲に制御して伸びを改善し、伸線時の加工性を向上させている。伸線加工工程Ｓ２における減面率は８９％以上９９．５％以下とすることが好ましいが、これに限定されない。 When the wire drawing step S2 is performed within the range of the area reduction rate of 80% or more and 99.6% or less with respect to the strand produced in the hot working step S1, the crystal grains become fibrous in the drawing direction. An elongated metal structure is formed, and the (001) plane increases in a cross section perpendicular to the drawing direction. When the metal structure elongated in a fibrous form is further subjected to wire drawing, the elongation may be small (it is difficult to elongate) and may break. Therefore, by performing the heat treatment step S3 under the above-described conditions, a part of the metal structure elongated in a fibrous form is recrystallized to improve the elongation by controlling the area ratio of the (001) plane to a predetermined range, Workability during wire drawing is improved. The area reduction rate in the wire drawing step S2 is preferably 89% or more and 99.5% or less, but is not limited thereto.
　また、加熱処理工程Ｓ３においては、伸線加工工程Ｓ２で伸線された素線に対して、バッチ式焼鈍炉によって、２００℃以上２６０℃以下、３０分以上３００分以下の範囲内で加熱処理を行う。このため、伸線方向と垂直な断面における（００１）面の面積率を１５％以上３０％以下に確実に制御することができる。 In addition, in the heat treatment step S3, the wire drawn in the wire drawing step S2 is subjected to a heat treatment within a range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes by a batch annealing furnace. I do. For this reason, the area ratio of the (001) plane in the cross section perpendicular to the wire drawing direction can be reliably controlled to 15% or more and 30% or less.
　加熱処理工程Ｓ３において、加熱温度が２００℃未満の場合、再結晶粒が十分に発生せず（００１）面の面積率を３０％以下に制御することが困難となるので、伸びが低下し、その結果伸線加工時に破断が発生するおそれがある。また、加熱温度が２６０℃超の場合、再結晶が進行し過ぎて（００１）面の面積率を１５％以上に制御することが困難となるので、強度が低下し、伸線加工時に破断し易くなってしまう。加熱処理工程Ｓ３における加熱温度は２１０℃以上２５０℃以下とすることが好ましいが、これに限定されない。 In the heat treatment step S3, when the heating temperature is less than 200 ° C., recrystallized grains are not sufficiently generated and it becomes difficult to control the area ratio of the (001) plane to 30% or less, so that the elongation decreases. As a result, breakage may occur during the wire drawing process. When the heating temperature is higher than 260 ° C., recrystallization proceeds too much and it becomes difficult to control the area ratio of the (001) plane to 15% or more, so that the strength is reduced and breakage occurs during wire drawing. It becomes easy. The heating temperature in the heat treatment step S3 is preferably 210 ° C. or higher and 250 ° C. or lower, but is not limited thereto.
　また、加熱処理工程Ｓ３において、加熱時間が３０分未満の場合、再結晶粒が十分に発生せず（００１）面の面積率を３０％以下に制御することが困難となる。また、加熱時間が３００分超の場合、再結晶が進行し過ぎて（００１）面の面積率を１５％以上に制御することが困難となる。加熱温度は６０分以上１８０分以下とすることが好ましいが、これに限定されない。
　以上の理由により、加熱処理工程の熱処理条件は、２００℃以上２６０℃以下、３０分以上３００分以下の範囲内とされている。 In the heat treatment step S3, when the heating time is less than 30 minutes, sufficient recrystallized grains are not generated, and it becomes difficult to control the area ratio of the (001) plane to 30% or less. When the heating time exceeds 300 minutes, recrystallization proceeds too much, and it becomes difficult to control the area ratio of the (001) plane to 15% or more. The heating temperature is preferably 60 minutes or more and 180 minutes or less, but is not limited thereto.
For the above reasons, the heat treatment conditions of the heat treatment step are set in the range of 200 ° C. to 260 ° C. and 30 minutes to 300 minutes.
　例えば、電流焼鈍のような高温短時間の加熱処理では、伸線加工によって形成された繊維状の組織中に再結晶組織を安定して形成することができず、伸線方向と垂直な断面における（００１）面の面積率を上述の範囲に制御することが困難となる。一方、本実施形態では、バッチ式焼鈍炉を用いて上述の加熱条件で加熱処理を行うことにより、安定して（００１）面の面積率を上述の範囲に制御することができるのである。 For example, in a high-temperature short-time heat treatment such as current annealing, a recrystallized structure cannot be stably formed in a fibrous structure formed by wire drawing, and in a cross section perpendicular to the wire drawing direction. It becomes difficult to control the area ratio of the (001) plane within the above range. On the other hand, in this embodiment, the area ratio of the (001) plane can be stably controlled within the above range by performing the heat treatment under the above heating conditions using a batch annealing furnace.
　以上、本発明の実施形態について説明したが、本発明はこれに限定されることはなく、その発明の技術的思想を逸脱しない範囲で適宜変更可能である。 As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
　なお、純度９９．９９９９質量％以上の高純度銅からなる鋳塊の形状やサイズに限定はなく、本実施形態に限定されることはない。 In addition, there is no limitation in the shape and size of the ingot which consists of high purity copper of purity 99.9999 mass% or more, and it is not limited to this embodiment.
　以下に、本発明の有効性を確認するために行った確認実験の結果について説明する。
（本発明例１～５）
　まず、純度９９．９９９９質量％以上の高純度銅からなる直径２５０ｍｍ、長さ７００ｍｍのビレットを用意した。このビレットを８００℃に加熱し、熱間押出し加工を行い、直径８ｍｍの素線を製出した。
　次に、直径８ｍｍの素線に対して、冷間皮剥ぎ伸線を含め、直径１ｍｍまで伸線加工を行った。なお、この伸線加工は、減面率９８％とし、パス回数は１５回とした。
　次いで、伸線加工された素線をバッチ式焼鈍炉に装入して、表１に示す加熱温度、加熱時間で加熱処理を行った。なお、バッチ式焼鈍炉の雰囲気は、還元雰囲気とした。
　以上のようにして、本発明例１～５のボンディングワイヤ用銅素線を製造した。 Below, the result of the confirmation experiment performed in order to confirm the effectiveness of this invention is demonstrated.
(Invention Examples 1 to 5)
First, a billet having a diameter of 250 mm and a length of 700 mm made of high-purity copper having a purity of 99.9999% by mass or more was prepared. The billet was heated to 800 ° C. and subjected to hot extrusion to produce a strand having a diameter of 8 mm.
Next, a wire having a diameter of 1 mm was drawn to a diameter of 1 mm, including cold peel drawing. In this wire drawing, the area reduction rate was 98%, and the number of passes was 15.
Next, the drawn wire was placed in a batch annealing furnace, and heat treatment was performed at the heating temperature and heating time shown in Table 1. The atmosphere of the batch type annealing furnace was a reducing atmosphere.
As described above, the copper wires for bonding wires according to Examples 1 to 5 of the present invention were manufactured.
（比較例１）
　比較例１では、伸線加工後の加熱処理を行わずにボンディングワイヤ用銅素線を製造した。すなわち、伸線加工後の加熱処理を行わないこと以外は、上述した本発明例と同様にして、比較例１のボンディングワイヤ用銅素線を製造した。 (Comparative Example 1)
In Comparative Example 1, a copper wire for bonding wire was manufactured without performing heat treatment after wire drawing. That is, a copper wire for bonding wire of Comparative Example 1 was manufactured in the same manner as the above-described example of the present invention except that the heat treatment after the wire drawing was not performed.
（比較例２）
　まず、純度９９．９９９９％以上の高純度銅からなる鋳塊を用意した。この鋳塊を原料として直径８ｍｍの素線を鋳造した。
　次に、直径８ｍｍの素線に対して、冷間皮剥ぎ伸線を含め、直径１ｍｍまで伸線加工を行った。なお、この伸線加工は、減面率９８％とし、パス回数は１５回とした。
　このようにして、比較例２のボンディングワイヤ用銅素線を製造した。なお、比較例２においても、伸線加工後の加熱処理を行っていない。 (Comparative Example 2)
First, an ingot made of high-purity copper having a purity of 99.9999% or more was prepared. Using this ingot as a raw material, a strand having a diameter of 8 mm was cast.
Next, a wire having a diameter of 1 mm was drawn to a diameter of 1 mm, including cold peel drawing. In this wire drawing, the area reduction rate was 98%, and the number of passes was 15.
Thus, the copper wire for bonding wires of Comparative Example 2 was produced. In addition, also in the comparative example 2, the heat processing after a wire drawing process are not performed.
　上述のようにして製造されたボンディングワイヤ用銅素線において、伸線方向に垂直な断面のＥＢＳＤ測定を行い、（００１）面の面積率を測定した。
　ＥＢＳＤ測定の手順について以下に説明する。まず、ボンディングワイヤ用銅素線の伸線方向に垂直な断面を耐水研磨紙、及びダイヤモンド砥粒を用いて機械研磨した後、コロイダルシリカ溶液を用いて仕上げ研磨した。そして、ＥＢＳＤ測定装置（ＨＩＴＡＣＨＩ社製　Ｓ４３００－ＳＥＭ、ＥＤＡＸ／ＴＳＬ社製　ＯＩＭ　Ｄａｔａ　Ｃｏｌｌｅｃｔｉｏｎ）と、解析ソフト（ＥＤＡＸ／ＴＳＬ社製　ＯＩＭ　Ｄａｔａ　Ａｎａｌｙｓｉｓ　ｖｅｒ．５．２）によって、ボンディングワイヤ用銅素線の伸線方向に垂直な断面の結晶方位を測定した。具体的には、試料表面（ボンディングワイヤ用銅素線の伸線方向に垂直な断面）の測定範囲内の個々の測定点に電子線を照射し、電子線を試料表面に２次元で走査させ、後方散乱電子線回折による方位解析を行った。なお、測定点間隔を１．８０μｍとし、６００μｍ×９４０μｍの領域についてＥＢＳＤ測定を行った。
　なお、ＥＢＳＤ測定されるボンディングワイヤ用銅素線の断面において、（００１）面に対してズレ角１５°以内の結晶面（（００１）面との為す角度が１５°以内にある結晶面）を（００１）面とみなして、測定領域における（００１）面の面積率を評価した。 In the copper wire for bonding wire manufactured as described above, EBSD measurement was performed on a cross section perpendicular to the drawing direction, and the area ratio of the (001) plane was measured.
The EBSD measurement procedure will be described below. First, a cross section perpendicular to the wire drawing direction of the copper wire for bonding wire was mechanically polished using water-resistant abrasive paper and diamond abrasive grains, and then finish-polished using a colloidal silica solution. Then, an EBSD measuring device (HITACHI S4300-SEM, EDAX / TSL OIM Data Collection) and analysis software (EDAX / TSL OIM Data Analysis ver.5.2) The crystal orientation of the cross section perpendicular to the drawing direction was measured. Specifically, an electron beam is irradiated to each measurement point within the measurement range of the sample surface (cross section perpendicular to the drawing direction of the copper wire for bonding wire), and the electron beam is scanned two-dimensionally on the sample surface. Then, orientation analysis by backscattered electron diffraction was performed. In addition, the measurement point interval was 1.80 μm, and EBSD measurement was performed on an area of 600 μm × 940 μm.
In the cross section of the copper wire for bonding wire measured by EBSD, a crystal plane with a deviation angle of 15 ° or less (crystal plane with an angle of (001) plane within 15 °) with respect to the (001) plane. Considering it as the (001) plane, the area ratio of the (001) plane in the measurement region was evaluated.
　また、製造されたボンディングワイヤ用銅素線に対して、さらに伸線加工を行い、直径５μｍまで加工した。具体的には、直径１ｍｍ（１０００μｍ）から１００μｍに伸線加工を行い、さらに１００μｍから５０μｍ、５０μｍから２５μｍ、２５μｍから１０μｍ、１０μｍから５μｍのように伸線加工した。このとき、１００μｍから５μｍまで各直径に加工する際に断線した回数を測定した。なお、この伸線加工は、５μｍまで加工した段階で、全長１００ｍのワイヤが得られるように実施した。
　なお、比較例１については、伸線加工において、断線が多発したため、途中でワイヤの製造（伸線加工）を中止した。
　上記の測定結果を表１に示す。 Further, the manufactured copper wire for bonding wire was further drawn to a diameter of 5 μm. Specifically, wire drawing was performed from a diameter of 1 mm (1000 μm) to 100 μm, and wire drawing was further carried out to 100 μm to 50 μm, 50 μm to 25 μm, 25 μm to 10 μm, and 10 μm to 5 μm. At this time, the number of times of disconnection when processing each diameter from 100 μm to 5 μm was measured. In addition, this wire drawing process was implemented so that the wire of 100 m of full length might be obtained in the step processed to 5 micrometers.
In Comparative Example 1, since wire breakage occurred frequently in the wire drawing process, the production of the wire (drawing process) was stopped halfway.
The measurement results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　本発明例１～５は、表１に示すように、１００μｍから５μｍまで伸線加工を施しても断線回数が少なく、加工性が良好であることが確認された。すなわち、本発明例１～５は、細線化しても断線が生じ難いボンディングワイヤ用銅素線であることが確認された。 As shown in Table 1, it was confirmed that Examples 1 to 5 of the present invention had good workability because the number of wire breaks was small even when wire drawing was performed from 100 μm to 5 μm. In other words, it was confirmed that Examples 1 to 5 of the present invention are copper wires for bonding wires that are less likely to be broken even if they are thinned.
　比較例１は、直径１ｍｍまで伸線加工した後に、加熱処理が行われていないので、（００１）面の面積率が３０％超となり、断線回数が本発明例と比較して多くなった。
　また、比較例２は、直径８ｍｍの素線を鋳造し、この素線を直径１ｍｍまで伸線加工しており、直径１ｍｍまでの伸線加工の減面率が本発明例と比較して不足しているために、（００１）面の面積率が１５％未満となり、断線回数が本発明例と比較して多くなった。 In Comparative Example 1, since the heat treatment was not performed after the wire was drawn to a diameter of 1 mm, the area ratio of the (001) plane was over 30%, and the number of disconnections was increased compared to the inventive example.
In Comparative Example 2, an element wire having a diameter of 8 mm is cast, and the element wire is drawn to a diameter of 1 mm. The area reduction rate of the drawing process to a diameter of 1 mm is insufficient as compared with the example of the present invention. For this reason, the area ratio of the (001) plane was less than 15%, and the number of disconnections increased compared to the inventive example.
　本発明に係るボンディングワイヤ用銅素線によれば、加工性が良好で、細線化しても断線が生じ難いので、ボンディングワイヤの細線化が可能となる。 According to the copper wire for bonding wire according to the present invention, the workability is good and disconnection hardly occurs even if the wire is thinned, so that the bonding wire can be thinned.
Ｓ１　熱間加工工程
Ｓ２　伸線加工工程
Ｓ３　加熱処理工程 S1 Hot working process S2 Wire drawing process S3 Heat treatment process

Claims (4)

  1. 　ボンディングワイヤを形成するためのボンディングワイヤ用銅素線であって、
    　純度が９９．９９９９質量％以上の高純度銅からなり、
    　線径が０．５ｍｍ以上３．５ｍｍ以下であり、
    　伸線方向と垂直な断面において（００１）面の面積率が１５％以上３０％以下であることを特徴とするボンディングワイヤ用銅素線。     A copper wire for bonding wire for forming a bonding wire,
    It consists of high-purity copper with a purity of 99.9999% by mass or more,
    The wire diameter is 0.5 mm or more and 3.5 mm or less,
    A copper wire for bonding wire, wherein the area ratio of the (001) plane is 15% or more and 30% or less in a cross section perpendicular to the drawing direction.
  2. 　純度９９．９９９９質量％以上の高純度銅からなる鋳塊を熱間加工して素線を製出する熱間加工工程と、
    　製出された前記素線を減面率８０％以上９９．６％以下の範囲内で冷間伸線加工をする伸線加工工程と、
    　伸線加工された前記素線に対して２００℃以上２６０℃以下、３０分以上３００分以下の範囲内で加熱処理を行う加熱処理工程と、
    　を備えるボンディングワイヤ用銅素線の製造方法。     A hot working step of hot-working an ingot made of high-purity copper having a purity of 99.9999% by mass or more to produce a strand;
    A wire drawing process for subjecting the produced wire to cold wire drawing within a range of 80% to 99.6% in area reduction rate;
    A heat treatment step of performing heat treatment on the drawn wire in a range of 200 ° C. to 260 ° C., 30 minutes to 300 minutes;
    The manufacturing method of the copper strand for bonding wires provided with this.
  3. 　前記熱間加工が、７００℃以上９００℃以下の温度で減面率９９％以上９９．９５％以下まで行われる熱間押出し加工である、請求項２に記載のボンディングワイヤ用銅素線の製造方法。 The said hot working is manufacture of the copper strand for bonding wires of Claim 2 which is a hot extrusion process performed to the area reduction rate of 99% or more and 99.95% or less at the temperature of 700 degreeC or more and 900 degrees C or less. Method.
  4. 　前記加熱処理工程においてバッチ式焼鈍炉を用いて前記素線を加熱する、請求項２または３に記載のボンディングワイヤ用銅素線の製造方法。 The manufacturing method of the copper strand for bonding wires of Claim 2 or 3 which heats the said strand using a batch-type annealing furnace in the said heat processing process.
PCT/JP2014/075999 2013-10-10 2014-09-30 Bonding-wire copper strand, and manufacturing method for bonding-wire copper strand WO2015053128A1 (en)

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WO2019031497A1 (en) * 2017-08-09 2019-02-14 日鉄ケミカル＆マテリアル株式会社 Cu ALLOY BONDING WIRE FOR SEMICONDUCTOR DEVICE

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Publication number Priority date Publication date Assignee Title
WO2019031498A1 (en) * 2017-08-09 2019-02-14 日鉄ケミカル＆マテリアル株式会社 Cu ALLOY BONDING WIRE FOR SEMICONDUCTOR DEVICE
WO2019031497A1 (en) * 2017-08-09 2019-02-14 日鉄ケミカル＆マテリアル株式会社 Cu ALLOY BONDING WIRE FOR SEMICONDUCTOR DEVICE
JPWO2019031497A1 (en) * 2017-08-09 2019-11-07 日鉄ケミカル＆マテリアル株式会社 Cu alloy bonding wire for semiconductor devices
JPWO2019031498A1 (en) * 2017-08-09 2020-01-09 日鉄ケミカル＆マテリアル株式会社 Cu alloy bonding wire for semiconductor device
CN110998814A (en) * 2017-08-09 2020-04-10 日铁化学材料株式会社 Cu alloy bonding wire for semiconductor device
TWI692822B (en) * 2017-08-09 2020-05-01 日商日鐵化學材料股份有限公司 Cu alloy bonding wire for semiconductor device
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CN110998814B (en) * 2017-08-09 2021-04-23 日铁化学材料株式会社 Cu alloy bonding wire for semiconductor device
US10991672B2 (en) 2017-08-09 2021-04-27 Nippon Steel Chemical & Material Co., Ltd. Cu alloy bonding wire for semiconductor device

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CN104904000A (en) 2015-09-09
PH12016500617B1 (en) 2016-06-13
TW201522673A (en) 2015-06-16
PH12016500617A1 (en) 2016-06-13
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KR101558138B1 (en) 2015-10-06
CN104904000B (en) 2019-05-17

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