WO2013015355A1 - Method of manufacturing oxide ceramic circuit board, and oxide ceramic circuit board - Google Patents

Method of manufacturing oxide ceramic circuit board, and oxide ceramic circuit board Download PDF

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Publication number
WO2013015355A1
WO2013015355A1 PCT/JP2012/068957 JP2012068957W WO2013015355A1 WO 2013015355 A1 WO2013015355 A1 WO 2013015355A1 JP 2012068957 W JP2012068957 W JP 2012068957W WO 2013015355 A1 WO2013015355 A1 WO 2013015355A1
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Prior art keywords
oxide
circuit board
copper plate
heating
ceramic circuit
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PCT/JP2012/068957
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French (fr)
Japanese (ja)
Inventor
隆之 那波
佐藤　英樹
星野　政則
裕 小森田
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株式会社東芝
東芝マテリアル株式会社
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Application filed by 株式会社東芝, 東芝マテリアル株式会社 filed Critical 株式会社東芝
Priority to CN201280037799.0A priority Critical patent/CN103717552B/en
Priority to KR1020147001936A priority patent/KR101548091B1/en
Priority to JP2013525748A priority patent/JP5908473B2/en
Publication of WO2013015355A1 publication Critical patent/WO2013015355A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • H01L23/3735—Laminates or multilayers, e.g. direct bond copper ceramic substrates
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    • C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
    • C04B37/02—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles
    • C04B37/021—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles in a direct manner, e.g. direct copper bonding [DCB]
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    • C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
    • C04B37/02—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles
    • C04B37/023—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles characterised by the interlayer used
    • C04B37/025—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles characterised by the interlayer used consisting of glass or ceramic material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
    • F27B9/24—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace being carried by a conveyor
    • F27B9/243—Endless-strand conveyor
    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4871—Bases, plates or heatsinks
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/20—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by affixing prefabricated conductor pattern
    • H05K3/202—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by affixing prefabricated conductor pattern using self-supporting metal foil pattern
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
    • C04B2235/661—Multi-step sintering
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    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
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    • C04B2235/963—Surface properties, e.g. surface roughness
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/02—Aspects relating to interlayers, e.g. used to join ceramic articles with other articles by heating
    • C04B2237/04—Ceramic interlayers
    • C04B2237/06—Oxidic interlayers
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/32—Ceramic
    • C04B2237/34—Oxidic
    • C04B2237/343—Alumina or aluminates
    • C—CHEMISTRY; METALLURGY
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/40—Metallic
    • C04B2237/407—Copper
    • C—CHEMISTRY; METALLURGY
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/54—Oxidising the surface before joining
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/70—Forming laminates or joined articles comprising layers of a specific, unusual thickness
    • C04B2237/708—Forming laminates or joined articles comprising layers of a specific, unusual thickness of one or more of the interlayers
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/86—Joining of two substrates at their largest surfaces, one surface being complete joined and covered, the other surface not, e.g. a small plate joined at it's largest surface on top of a larger plate
    • 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
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass

Definitions

  • the present invention relates to a method for manufacturing an oxide-based ceramic circuit board and an oxide-based ceramic circuit board, and more particularly to an oxide-based ceramic circuit board having excellent heat cycle (TCT) characteristics and a method for manufacturing the same.
  • TCT heat cycle
  • Ceramic substrates used as the base material for ceramic circuit boards include oxide ceramics such as aluminum oxide sintered bodies and mixed sintered bodies of aluminum oxide and zirconium oxide, and nitrides such as aluminum nitride sintered bodies and silicon nitride sintered bodies. Physical ceramics are used. In recent years, high thermal conductivity of nitride ceramics has been promoted. For this reason, nitride ceramic circuit boards are used in products that require high thermal conductivity. On the other hand, oxide-based ceramic substrates are used in products that do not require relatively high thermal conductivity because they are less expensive than nitride-based ceramics.
  • the copper circuit board and the oxide-based ceramic substrate can be bonded by a bonding method called a direct bonding method (DBC).
  • DBC direct bonding method
  • the direct bonding method uses an eutectic composition of oxygen and copper as described in, for example, Japanese Patent Application Laid-Open No. 1-59986 (Patent Document 1) and Japanese Patent Application Laid-Open No. 4-144978 (Patent Document 2). And joining them.
  • an excellent thermal cycle test (TCT test) durability is obtained by removing the oxide layer on the copper plate surface by etching the copper plate surface of the alumina circuit board. .
  • the etching process increases the cost.
  • an alumina circuit board that does not remove the oxide layer on the copper plate surface by performing an etching process has a problem that it is difficult to improve TCT characteristics.
  • the present invention has been made to solve the above problems, and an object thereof is to provide an oxide-based ceramic circuit board having excellent TCT characteristics and bonding strength using a direct bonding method.
  • the method for producing an oxide-based ceramic circuit board according to the present invention includes a step of forming a laminate by placing a copper plate on an oxide-based ceramic substrate, and a step of heating the obtained laminate.
  • the heating step comprises heating the laminate in a first heating region having a maximum heating temperature between 1065 and 1085 ° C.
  • heating the laminated body in the heating region to form a joined body, and thereafter cooling the joined body in the cooling region.
  • the heating step includes placing an oxide-based ceramic substrate on which a copper plate is disposed on a tray, and a belt having a conveyance speed (belt speed) of 70 to 270 mm / min. It is preferable to carry out using a belt furnace that performs each heating step continuously while conveying the tray with a conveyor.
  • the tray is preferably made of a nickel alloy.
  • the copper plate has a circuit structure in which a plurality of circuit elements and a bridge portion connecting the circuit elements are formed by press working, and the bridge portion is removed after joining the copper plate and the oxide-based ceramic substrate. It is preferable. Moreover, it is preferable to form a circuit structure by an etching process after joining the oxide ceramic substrate and the copper plate.
  • the belt furnace preferably includes a nitrogen gas atmosphere in which a ratio A / B of the nitrogen flow rate (A) of the entrance curtain and the nitrogen flow rate (B) of the exit curtain is controlled to be 0.2 or less.
  • the physical ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia.
  • the bonding strength of the copper plate is preferably 9.5 kgf / cm or more.
  • the carbon content in the copper plate is preferably 0.1 to 1.0% by mass.
  • the oxide-based ceramic circuit board of the present invention is an oxide-based ceramic circuit board in which a copper plate and an oxide-based ceramic substrate are bonded by a direct bonding method.
  • the area ratio of copper on the bonding surface side is 60% or less per unit area of 3000 ⁇ m ⁇ 3000 ⁇ m, and the bonding strength of the copper plate is 9.5 kgf / cm or more.
  • the oxide ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia.
  • the oxide-based ceramic circuit board is held at a temperature of ⁇ 40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C.
  • the oxide ceramic substrate preferably has a density of 3.60 to 3.79 g / cm 3 .
  • the oxide-based ceramic circuit board is held at a temperature of ⁇ 40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C. for 30 minutes, and then at a temperature of 25 ° C. for 10 minutes.
  • the copper plate After 100 cycles of a heat cycle test (TCT) in which the heating step for 1 minute is one cycle, the copper plate preferably has a bonding strength of 6.5 kgf / cm or more.
  • the copper plate preferably has a thickness of 0.2 to 0.5 mm.
  • the surface roughness Ra of the oxide ceramic substrate is preferably 0.1 to 0.7 ⁇ m.
  • oxygen exists in the crystal grain boundary of the said copper plate.
  • the average crystal grain size of the copper plate is preferably 300 to 800 ⁇ m.
  • the carbon content of the copper plate is preferably 0.1 to 1.0% by mass.
  • the oxide-based ceramic circuit board according to the present invention since the heating process is performed in the predetermined first heating region, second heating region, and third heating region, the eutectic bonding reaction is stabilized. Therefore, the manufacturing yield of the ceramic circuit board can be improved.
  • the oxide-based ceramic circuit board according to the present invention has high bonding strength and can improve TCT characteristics.
  • the method for manufacturing an oxide-based ceramic circuit board includes an oxide ceramic substrate including a step of forming a laminate by placing a copper plate on an oxide-based ceramic substrate and a step of heating the obtained laminate.
  • the heating step includes the step of heating the laminate in a first heating region having a maximum heating temperature between 1065 and 1085 ° C.
  • FIG. 1 shows an example of the configuration of an oxide ceramic circuit board.
  • reference numeral 1 is an oxide ceramic circuit board
  • reference numeral 11 is an oxide ceramic board
  • reference numeral 12 is a copper circuit board (copper board for circuit)
  • reference numeral 13 is a back metal plate (back copper board). It is.
  • the oxide-based ceramic substrate 11 is preferably one of an alumina sintered body and a mixed sintered body of alumina and zirconia.
  • the alumina sintered body may contain 8% by mass or less of a sintering aid such as an Si component, a Ca component, an Mg component, or an Na component.
  • the mixed sintered body of alumina and zirconia is preferably a sintered body of 10 to 90% by mass of zirconia and the remaining alumina. In addition, you may contain 8 mass% or less of sintering adjuvant as needed.
  • the copper plate is preferably a copper plate made of tough pitch electrolytic copper containing 100 to 1000 ppm by mass of oxygen.
  • the method of forming the copper oxide film include a method of directly oxidizing the copper plate by heat treatment, a method of applying a paste of copper oxide powder, and the like. Specifically, it can be formed by performing a surface oxidation treatment in which a copper plate is heated in the atmosphere at a temperature of 150 to 360 ° C. for 20 to 120 seconds.
  • the thickness of the copper oxide film is less than 1 ⁇ m, since the amount of Cu—O eutectic generated is small, there are many unbonded portions between the substrate and the copper circuit board, and the effect of improving the bonding strength is small. .
  • the thickness of the copper oxide layer formed on the copper circuit board surface is preferably in the range of 1 to 10 ⁇ m. For the same reason, the range of 2 to 5 ⁇ m is more desirable.
  • the copper plate preferably contains 0.1 to 1.0% by mass of carbon. Since carbon functions as a deoxidizer, it is possible to obtain an effect of moving oxygen in the copper plate (tough pitch copper or oxygen-free copper) to the copper plate surface. Oxygen that has migrated to the copper plate surface can be used to form a Cu—O eutectic during direct bonding. If the carbon content is less than 0.1% by mass, there is no effect of inclusion. If the carbon content exceeds 1.0% by mass, the carbon content is excessively increased and the conductivity of the copper plate is lowered.
  • the joining method used in the present invention is a direct joining method (DBC).
  • DBC direct joining method
  • the copper circuit board 12 and the back copper board 13 are placed in contact with each other on the oxide ceramic substrate 11 and heated to produce a eutectic liquid phase such as Cu—Cu 2 O and Cu—O at the bonding interface.
  • a eutectic liquid phase such as Cu—Cu 2 O and Cu—O at the bonding interface.
  • the wettability with the oxide ceramic substrate is increased by this liquid phase, and then the liquid ceramic phase is cooled and solidified to directly bond the oxide ceramic substrate and the copper plate.
  • a eutectic of copper and oxygen it is necessary to have a form in which copper and oxygen exist on the joint surface.
  • the formation of the eutectic liquid phase of copper and oxygen occurs at a temperature of 1065 ° C. or higher.
  • the heating step includes a first heating region having a maximum value between 1065 and 1085 ° C., and then a minimum between 1000 and 1050 ° C. A second heating region having a value, a third heating region having a maximum value between 1065 to 1120 ° C., and a cooling region thereafter.
  • FIG. 2 shows an example of a method for manufacturing an oxide-based ceramic circuit board according to the present invention.
  • reference numeral 1 is an oxide-based ceramic circuit board
  • 2 is a tray
  • 3 is a belt conveyor.
  • FIG. 2 illustrates a belt furnace 6 in which the tray 2 on which the oxide-based ceramic circuit board 1 before bonding is disposed is disposed on the belt conveyor 3 and the tray 2 is conveyed by the belt conveyor 3.
  • the belt furnace 6 is not limited as long as the first heating region, the second heating region, and the third heating region described later are provided.
  • a first heating region having a maximum heating temperature within a temperature range of 1065 to 1085 ° C. is formed.
  • the first heating region can be formed by adjusting the output temperature of a heater (not shown) in the portion corresponding to the first heating region.
  • a second heating region having a minimum heating temperature within a temperature range of 1000 to 1050 ° C. is formed, and then within a temperature range of 1065 to 1120 ° C.
  • a third heating region having a maximum value of the heating temperature is formed and the cooling process is continued.
  • the temperature can be adjusted by changing the output temperature of the heater in each region. It is necessary to continuously perform the heating process in the first heating region, the second heating region, and the third heating region. For this purpose, a method in which each temperature region is passed while being conveyed in the belt furnace 6 is preferable.
  • FIG. 3 shows an example of a temperature profile in the heating step in the method for manufacturing an oxide-based ceramic circuit board according to the present invention.
  • first heating region a temperature range of 1065 to 1085 ° C. where the eutectic reaction between copper and oxygen occurs
  • second heating region 1000 to 1064 ° C. where no eutectic reaction occurs.
  • the laminated body is heated to a temperature range (second heating region) and then heated again to a temperature range of 1065 to 1120 ° C. (third heating region) where a eutectic reaction occurs.
  • the heating temperature is increased, decreased, or increased, and each heating step is continuously performed.
  • the temperature profile may be set so as to be held at a constant temperature at which the maximum value or the minimum value is obtained.
  • the eutectic reaction is stabilized by providing a second heating region and heating at a temperature as low as 1000 to 1064 ° C., which is the temperature below the eutectic reaction, and thereafter, a temperature of 1065 to 1120 ° C. in the third heating region. Residual dendritic crystals can be removed by reheating in the range. In other words, the oxygen that has formed dendritic crystals can be released from the copper plate. Further, if the temperature of the second heating region is lower than 1000 ° C., the temperature is excessively lowered, and the dendritic crystals are not sufficiently removed in the third heating region.
  • the heating temperature range is 1020 to 1050 ° C.
  • a more preferable heating temperature range is 1070 to 1090 ° C.
  • the temperature of the third heating region is higher than the heating temperature of the first heating region.
  • the heating process is performed by continuously placing an oxide ceramic substrate (laminated body) on which a copper plate is placed on a tray, and continuously conveying the tray with a belt conveyor having a belt speed of 70 to 270 mm / min. It is preferable to use a belt furnace that implements the above.
  • the heat treatment time can be adjusted by controlling the belt speed. When the belt speed is less than 70 mm / min, the number of treatments (tact) per unit time is reduced, and in particular, excessive heat treatment in the first heating area further promotes dendrite generation, and the second heating area and the third heating area. It cannot be removed in the area.
  • the belt speed is higher than 270 mm / min, the joining in the first and third heating regions is insufficient, and there is a risk of causing defects such as peeling of the copper plate.
  • the belt speed is preferably in the range of 100 to 220 mm / min. Further, when continuously transporting using the above-described transport speed, it is preferable that the first heating region, the second heating region, and the third heating region each have a transport distance of 300 to 2000 mm.
  • the tray which conveys an oxide type ceramic circuit board is comprised with a nickel alloy.
  • the tray is conveyed to a heat treatment furnace (belt furnace) in contact with a copper plate or an oxide ceramic substrate.
  • a heat treatment furnace belt furnace
  • the material does not react with copper or an oxide-based ceramic substrate at a temperature of about 1065 to 1120 ° C. used in the direct bonding method.
  • the oxide ceramic circuit board is more effective in preventing warpage if a copper plate is disposed on both sides and bonded. Therefore, it is desired that the material does not react with the copper plate at the heat treatment temperature and does not deform by heat.
  • Inconel there is a nickel alloy as such a material, and inconel containing a predetermined amount of chromium and iron is particularly preferable.
  • Typical examples of Inconel include Inconel 600 (Ni 76.0, Cr 15.5, Fe 8.0 by mass%) and Inconel 601 (Ni 60.5, Cr 23.0, Fe 14.4, Al 1.4 by mass%).
  • Inconel 625, Inconel 718, and Inconel X750 can be used.
  • Inconel is used as a heat-resistant alloy and is preferable because it does not react with the copper plate and does not thermally deform. In order to more effectively prevent the reaction with the copper plate, it is effective to perform wet hydrogen treatment on the surface of the Inconel tray.
  • the direct bonding method utilizes a eutectic reaction between copper and oxygen, it is preferable that oxygen is not present more than necessary in the atmosphere in which the heating step is performed. For this reason, it is preferable to implement a heat joining process in inert atmosphere.
  • the inert atmosphere include nitrogen gas and argon gas. Among these, since nitrogen gas is more economical, it is preferable to use nitrogen gas.
  • the purity of the nitrogen gas is preferably a high purity gas of 99.9% or more, more preferably 99.99% or more.
  • the belt furnace 6 preferably includes a nitrogen gas atmosphere in which the ratio A / B of the nitrogen flow rate (A) of the entrance curtain and the nitrogen flow rate (B) of the exit curtain is controlled to 0.2 or less.
  • FIG. 4 shows a cross-sectional view of the belt furnace 6 for explaining the nitrogen flow rate.
  • an oxide-based ceramic circuit board (laminated body or bonded body) 1 is placed on a tray 2 and is transported from a carry-in port (inlet) 4 side to a carry-out port (belt conveyor) 3 by a carrying belt (belt conveyor) 3. It is transported to the exit 5 side at a predetermined transport speed.
  • An entrance curtain is provided near the carry-in port 4 of the belt furnace 6, while an exit curtain is provided near the carry-out port 5.
  • A indicates the nitrogen flow rate of the entrance curtain
  • B indicates the nitrogen flow rate of the exit curtain. That is, nitrogen gas flowing out at a nitrogen flow rate (A) flows in the vicinity of the carry-in port 4. Also, nitrogen gas flowing out at a nitrogen flow rate (B) flows in the vicinity of the carry-out port 5.
  • the nitrogen flow rate ratio A / B being 0.2 or less indicates that the nitrogen flow rate B is flowing at a flow rate that is at least five times greater than the nitrogen flow rate A. With such a relationship, a flow of nitrogen gas is formed from the carry-out port 5 toward the carry-in port 4.
  • the nitrogen flow rate (A) is preferably 2 to 20 liters / minute.
  • the nitrogen flow rate (B) is preferably 30 to 100 liters / minute. Within these ranges, it is easy to control the nitrogen flow rate.
  • the nitrogen flow rate in the vicinity of the carry-in port 4 is set to 2 liters / minute or more, it can function as an airflow curtain that prevents impurities such as the atmosphere and dust from entering from the carry-in port 4.
  • the nitrogen flow rate at the carry-out port 5 to 30 liters / min or more, it is possible to effectively prevent impurities such as the atmosphere and dust from entering the carry-out port 5. In terms of preventing impurities from entering, it is also effective to flow heated nitrogen gas.
  • the heating temperature of nitrogen gas is preferably in the range of 50 to 180 ° C. If the temperature is less than 50 ° C., the effect of heating the nitrogen gas is not sufficient.
  • the first method is to form a circuit structure provided with a plurality of circuit board elements and a bridge portion for connecting them together by pressing a copper plate.
  • the second method is a method in which a copper plate is disposed on an oxide-based ceramic substrate, and a circuit structure having a predetermined shape is formed by an etching process after bonding.
  • a resin binder is applied on an oxide ceramic substrate and a copper plate is disposed thereon.
  • the resin binder is not particularly limited as long as it is burned off in the heating step.
  • examples of such a resin binder include an acrylic binder (for example, isobutyl methacrylate).
  • the resin binder is preferably applied in the form of dots having a diameter of 10 mm or less. The resin binder is burned away by the heating process, but if it is applied to the entire surface on which the copper plate is placed, gas components such as carbon dioxide generated at the time of burning are not fully removed from the gap between the oxide-based ceramic substrate and the copper plate.
  • the bonding strength of the copper plate can be set to 9.5 kgf / cm or more.
  • the oxide-based ceramic circuit board according to the present embodiment is basically obtained by the method for manufacturing an oxide-based ceramic circuit board according to the present invention. It is not particularly limited.
  • the structure of the oxide ceramic circuit board according to the present embodiment will be described below.
  • the oxide-based ceramic circuit board according to the present embodiment includes an oxide-based ceramic circuit board obtained by bonding a copper plate and an oxide-based ceramic substrate by a direct bonding method.
  • the area ratio of copper on the bonding surface side is 60% or less per unit area of 3000 ⁇ m ⁇ 3000 ⁇ m, and the bonding strength of the copper plate is 9.5 kgf / cm or more.
  • the oxide-based ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia.
  • the alumina sintered body may contain 8% by mass or less of a sintering aid such as an Si component, a Ca component, an Mg component, or an Na component.
  • the mixed sintered body of alumina and zirconia is preferably a sintered body of 10 to 90% by mass of zirconia and the remaining alumina. In addition, you may contain 8 mass% or less of sintering adjuvant as needed.
  • the density of the oxide-based ceramic substrate is preferably 3.60 to 3.79 g / cm 3 .
  • the thickness of the oxide-based ceramic substrate is preferably 0.3 to 1.2 mm.
  • the copper plate As a constituent material of the copper plate, tough pitch copper containing a predetermined amount of oxygen may be used, but a copper plate having a low oxygen content may be used.
  • the thickness of the copper plate is preferably 0.2 to 0.5 mm. While the thickness of the oxide ceramic substrate is in the range of 0.3 to 1.2 mm, the difference in thermal expansion between the oxide ceramic substrate and the copper plate is achieved by setting the thickness of the copper plate to 0.2 to 0.5 mm. This improves the durability in the heat cycle test (TCT test).
  • the copper plate preferably contains 0.1 to 1.0% by mass of carbon. Since carbon functions as a deoxidizer, it is possible to obtain an effect of moving oxygen in the copper plate (tough pitch copper or oxygen-free copper) to the copper plate surface.
  • the oxygen that has moved to the surface of the copper plate can be used to form a Cu—O eutectic when performing the direct bonding method. If the carbon content is less than 0.1% by mass, the effect of inclusion is not obtained. On the other hand, if the carbon content exceeds 1.0% by mass, the carbon content is excessively increased and the conductivity of the copper plate is lowered. Further, when performing the direct bonding method, the surface roughness of the oxide ceramic substrate is preferably 0.1 to 0.7 ⁇ m in Ra. If the surface roughness Ra is less than 0.1 ⁇ m, highly accurate surface polishing is required, which increases costs.
  • the surface roughness Ra exceeds 0.7 ⁇ m, the surface is too rough and a gap is formed between the copper plate and the oxide-based ceramic substrate, and the eutectic reaction may not proceed sufficiently.
  • the area ratio of copper on the bonding surface side of the copper plate with the oxide ceramic substrate when the bonded copper plate is peeled off is a unit. The area may be 60% or less per 3000 ⁇ m ⁇ 3000 ⁇ m.
  • the copper area ratio on the bonding surface side of the copper plate with the oxide-based ceramic substrate is determined by the surface analysis by EPMA on the bonding surface side of the peeled copper plate with the oxide-based ceramic substrate.
  • the most detected area is 60% or less per unit area of 3000 ⁇ m ⁇ 3000 ⁇ m.
  • An area ratio of copper of 60% or less per unit area indicates that a portion peeled from the oxide ceramic substrate is attached to the remaining portion. That is, in the remaining part, it shows that joining of the copper plate and the oxide-based ceramic substrate is uniformly performed over the entire surface.
  • a more preferable area ratio of copper is 40% or less.
  • the measurement may be performed by dividing into a plurality of visual fields.
  • the average crystal grain size of the copper plate after bonding is preferably 300 to 800 ⁇ m.
  • the direct bonding method is a bonding method using a eutectic reaction between copper and oxygen.
  • the oxygen in the copper plate or on the surface of the copper plate collects at the crystal grain boundaries of the copper plate. Since oxygen collected at the grain boundaries is used for the eutectic reaction, it is preferable that the grain boundaries of the copper plate have an appropriate size. If the average crystal grain size of the copper plate is smaller than 300 ⁇ m, the grain boundary phase is too small or too thin, resulting in a decrease in bonding strength.
  • the average crystal grain size exceeds 800 ⁇ m, the grain boundary phase becomes too large and the ratio of the copper crystal grain boundary per unit area is reduced, leading to a reduction in bonding strength.
  • the bonding strength can be improved and the TCT characteristics can be further improved.
  • oxygen is agglomerated at the copper crystal grain boundary by performing surface analysis of oxygen on the bonding surface side of the peeled copper plate by EPMA.
  • the bonding strength of the copper plate after performing 100 cycles of the TCT test in which one cycle is ⁇ 40 ° C. ⁇ 30 minutes ⁇ 25 ° C. ⁇ 10 minutes ⁇ 125 ° C. ⁇ 30 minutes ⁇ 25 ° C. ⁇ 10 minutes is 6.5 kgf / cm It can also be set as above.
  • the bonding strength between the oxide-based ceramic substrate and the copper plate is improved by aggregating oxygen in the copper crystal grain size of the copper plate or the grain boundary phase of the copper plate. Can do. Therefore, it is possible to provide an oxide-based ceramic circuit board with particularly improved TCT characteristics. With such a circuit board, it is possible to provide a ceramic circuit board with high cost merit utilizing the characteristics of an inexpensive oxide-based ceramic board.
  • an alumina substrate (length 50 mm ⁇ width 30 mm ⁇ thickness 0.4 mm, surface roughness Ra 0.3 ⁇ m, density 3.72 g / cm 3 ) was prepared.
  • a tough pitch copper plate (length 40 mm ⁇ width 20 mm ⁇ thickness 0.5 mm, average crystal grain size 50 ⁇ m) having an oxygen content of 500 mass ppm was prepared as a copper plate for a metal circuit board.
  • a tough pitch copper plate (length 40 mm ⁇ width 20 mm ⁇ thickness 0.5 mm was prepared as the copper plate for the back copper plate with an oxygen content of 500 mass ppm.
  • the carbon content in the copper plate was less than 0.1 mass%.
  • a belt furnace 6 as shown in FIG. 4 is used to carry out a direct bonding method by performing a heating process having a first heating region, a second heating region, and a third heating region shown in Table 1, and examples 1 to 5 was prepared.
  • region was unified at 1000 mm.
  • the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 1.
  • An oxide-based ceramic circuit board according to Comparative Example 1 was prepared by performing the same process as in Example 1 except that the direct bonding method was performed in the heating process in which the second heating process and the third heating process were not performed.
  • an alumina substrate (length 50 mm ⁇ width 30 mm ⁇ thickness 0.4 mm, surface roughness Ra 0.5 ⁇ m, density 3.68 g / cm 3 ) was prepared.
  • a pure copper plate (40 mm long ⁇ 20 mm wide ⁇ 0.5 mm thickness, average crystal grain size 60 ⁇ m) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for a metal circuit board.
  • a pure copper plate (length 40 mm ⁇ width 20 mm ⁇ thickness 0.5 mm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for the back copper plate.
  • the carbon content in a copper plate used the copper material less than 0.1 mass%.
  • the alumina substrate bonding surface side of the pure copper plate was heated to form a 4 ⁇ m thick copper oxide film. Then, it arranged on the tray made from Inconel 600 as a laminated body in the order of back copper plate / alumina substrate / copper circuit board. Next, using a belt furnace 6 as shown in FIG. 4, a heating process having a first heating region, a second heating region, and a third heating region shown in Table 2 is performed and a direct bonding method is performed. Oxide ceramic circuit boards according to Examples 6 to 9 were prepared.
  • region was unified at 1000 mm.
  • the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 2.
  • Example 10 As an oxide ceramic substrate, an alumina substrate (length 50 mm ⁇ width 30 mm ⁇ thickness 0.4 mm, surface roughness Ra 0.5 ⁇ m, density 3.68 g / cm 3 ) was prepared.
  • a pure copper plate (length 40 mm ⁇ width 20 mm ⁇ thickness 0.5 mm, average crystal grain size 60 ⁇ m) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for a metal circuit board. Furthermore, a pure copper plate (length 40 mm ⁇ width 20 mm ⁇ thickness 0.5 mm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for the back copper plate. In addition, the carbon content in a copper plate used the copper material less than 0.1 mass%. On the other hand, the copper plate for copper circuit boards was pressed to form two circuit elements each having a length of 15 mm and a width of 6 mm, and copper plates connected by a bridge structure were prepared.
  • the back copper plate / alumina substrate / copper circuit board was stacked in this order on the Inconel 600 tray, and arranged as a laminate.
  • a heating process having a first heating region, a second heating region, and a third heating region shown in Table 2 is performed and a direct bonding method is performed.
  • An oxide-based ceramic circuit board according to Example 10 was prepared.
  • region was unified at 1000 mm.
  • the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 2.
  • the copper circuit board was etched to form two circuit portions of 15 mm length ⁇ 6 mm width.
  • the bridge portion of the copper circuit board was deleted.
  • the bonding strength of the copper circuit board was determined. Also, 100 cycles of TCT test with -40 ° C. ⁇ 30 minutes ⁇ 25 ° C. ⁇ 10 minutes ⁇ 125 ° C. ⁇ 30 minutes ⁇ 25 ° C. ⁇ 10 minutes as one cycle. The bonding strength of was measured.
  • the area ratio of the copper by the side of the joint surface of a copper plate when peeling a copper circuit board was calculated
  • the area ratio was measured by EPMA analysis of the bonded surface side of the peeled copper plate, and the area ratio at which the most copper was detected was determined at a rate per unit area of 3000 ⁇ m ⁇ 3000 ⁇ m.
  • the presence or absence of oxygen aggregation was investigated by surface analysis of EPMA.
  • the analysis of EPMA was obtained by continuously analyzing a unit area of 300 ⁇ m ⁇ 300 ⁇ m until a total area of 3000 ⁇ m ⁇ 3000 ⁇ m was obtained.
  • the average crystal grain size of the copper plate after joining was also measured.
  • Ni plating was given to the copper circuit board, and the wettability was investigated.
  • the wettability was evaluated as ⁇ when the Ni plating adhesion area to the copper circuit board was 100%, and ⁇ when 99% or less.
  • the measurement survey results are shown in Table 3.
  • Example 9 since the nitrogen gas flow rate control (A / B) was 1, the wettability with the Ni plating on the copper plate surface was lowered. Dentrite structure was confirmed on the surface of the copper circuit board. Moreover, since the comparative example 1 did not provide the 2nd heating area
  • Example 11 An oxide-based ceramic circuit board according to Example 11 was prepared by repeating the same process except that the copper plate of Example 1 was replaced with a tough pitch copper plate having a carbon content of 0.5 mass%. Further, the same treatment was repeated except that the copper plate of Example 6 was replaced with oxygen-free copper (pure copper) having a carbon content of 0.2% by mass to prepare an oxide-based ceramic circuit board according to Example 12.
  • Example 11 was replaced with a mixed sintered body of alumina and zirconia (zirconia 20 wt%, yttria 5 wt%, remainder of alumina).
  • a ceramic circuit board was prepared.
  • the same treatment was repeated except that the alumina substrate of Example 12 was replaced with a mixed sintered body of alumina and zirconia (zirconia 20 wt%, yttria 5 wt%, remaining alumina), and the oxide system according to Example 14 was repeated.
  • a ceramic circuit board was prepared. Thereafter, the same measurement as in Example 1 was performed on the circuit boards of Examples 11-14. The results are shown in Table 4 below.
  • the heating process is performed in each of the predetermined first heating region, second heating region, and third heating region. Since it can be stabilized, the manufacturing yield of the ceramic circuit board can be improved.
  • the oxide-based ceramic circuit board according to the present invention has high bonding strength and can improve TCT characteristics.

Abstract

This bonding method of an oxide ceramic circuit board involves bonding an oxide ceramic circuit board and a copper plate into a single body by means of a step for forming a laminate by arranging a copper plate on an oxide ceramic circuit board and a step for heating the obtained laminate, and is characterized in that the aforementioned heating step involves a step for heating the laminate in a first heating region having a maximum heating temperature between 1065-1085°C, a step for subsequently heating the laminate in a second heating region having a minimum heating temperature between 1000-1050°C, and a step for further forming an assembly by heating the laminate in a third heating region having a maximum heating temperature between 1065-1120°C, and by thereafter cooling the assembly in a cooling region. By means of the aforementioned configuration, oxide ceramic circuit board with excellent thermal cycle test (TCT) characteristics.

Description

酸化物系セラミックス回路基板の製造方法および酸化物系セラミックス回路基板Oxide ceramic circuit board manufacturing method and oxide ceramic circuit board
　本発明は、酸化物系セラミックス回路基板の製造方法および酸化物系セラミックス回路基板に係り、特に耐熱サイクル（ＴＣＴ）特性に優れた酸化物系セラミックス回路基板およびその製造方法に関する。 The present invention relates to a method for manufacturing an oxide-based ceramic circuit board and an oxide-based ceramic circuit board, and more particularly to an oxide-based ceramic circuit board having excellent heat cycle (TCT) characteristics and a method for manufacturing the same.
　従来から、パワートランジスターなどの半導体素子を搭載する回路基板として、セラミックス回路基板が広く使用されている。セラミックス回路基板の基材となるセラミックス基板としては、酸化アルミニウム焼結体や酸化アルミニウムと酸化ジルコニウムの混合焼結体などの酸化物系セラミックス、窒化アルミニウム焼結体や窒化珪素焼結体などの窒化物系セラミックスが使用されている。近年、窒化物系セラミックスの高熱伝導化が進められている。このため、高熱伝導性が要求される製品では窒化物系セラミックス回路基板が使われている。
　一方、酸化物系セラミックス基板は、窒化物系セラミックスと比較して安価であることから、比較的高熱伝導性が要求されない製品に使用されている。また、酸化物系セラミックス回路基板を製造する場合、直接接合法（ＤＢＣ：ｄｉｌｅｃｔ　ｂｏｎｄｉｎｇ　ｃｏｐｐｅｒ）と呼ばれる接合法により、銅回路板と酸化物系セラミックス基板との接合が可能である。窒化物系セラミックス基板の場合、接合剤としてＴｉ等の活性金属を含有する活性金属ろう材を使用する必要があるのに対し、直接接合法では、Ｔｉ等の活性金属の使用が不要であることから、コストメリットは大きい。
　直接接合法は、例えば、特開平１－５９９８６号公報（特許文献１）や特開平４－１４４９７８号公報（特許文献２）に記載されたように、酸素と銅との共晶組成物を利用して接合する方法である。 Conventionally, ceramic circuit boards have been widely used as circuit boards on which semiconductor elements such as power transistors are mounted. Ceramic substrates used as the base material for ceramic circuit boards include oxide ceramics such as aluminum oxide sintered bodies and mixed sintered bodies of aluminum oxide and zirconium oxide, and nitrides such as aluminum nitride sintered bodies and silicon nitride sintered bodies. Physical ceramics are used. In recent years, high thermal conductivity of nitride ceramics has been promoted. For this reason, nitride ceramic circuit boards are used in products that require high thermal conductivity.
On the other hand, oxide-based ceramic substrates are used in products that do not require relatively high thermal conductivity because they are less expensive than nitride-based ceramics. Moreover, when manufacturing an oxide-based ceramic circuit board, the copper circuit board and the oxide-based ceramic substrate can be bonded by a bonding method called a direct bonding method (DBC). In the case of a nitride-based ceramic substrate, it is necessary to use an active metal brazing material containing an active metal such as Ti as a bonding agent, whereas the direct bonding method does not require the use of an active metal such as Ti. Therefore, the cost merit is great.
The direct bonding method uses an eutectic composition of oxygen and copper as described in, for example, Japanese Patent Application Laid-Open No. 1-59986 (Patent Document 1) and Japanese Patent Application Laid-Open No. 4-144978 (Patent Document 2). And joining them.
特開平１－５９９８６号公報Japanese Unexamined Patent Publication No. 1-59986 特開平４－１４４９７８号公報JP-A-4-144978
　特許文献２に示す接合方法では、アルミナ回路基板の銅板表面をエッチングして銅板表面の酸化物層を除去することにより、熱サイクル試験（ＴＣＴ試験）の耐久性が優れたものが得られている。しかしながら、エッチング工程はコストアップの要因となる。一方、エッチング工程を行って銅板表面の酸化物層を除去しないアルミナ回路基板では、ＴＣＴ特性の向上を図ることが困難であるという問題があった。
　本発明は、上記のような問題を解決するためになされたものであり、直接接合法を使用してＴＣＴ特性並びに接合強度が優れた酸化物系セラミックス回路基板を提供することを目的とする。 In the joining method shown in Patent Document 2, an excellent thermal cycle test (TCT test) durability is obtained by removing the oxide layer on the copper plate surface by etching the copper plate surface of the alumina circuit board. . However, the etching process increases the cost. On the other hand, an alumina circuit board that does not remove the oxide layer on the copper plate surface by performing an etching process has a problem that it is difficult to improve TCT characteristics.
The present invention has been made to solve the above problems, and an object thereof is to provide an oxide-based ceramic circuit board having excellent TCT characteristics and bonding strength using a direct bonding method.
　本発明に係る酸化物系セラミックス回路基板の製造方法は、酸化物系セラミックス基板上に銅板を配置して積層体を形成する工程と、得られた積層体を加熱する工程とにより、酸化物系セラミックス基板と銅板とを一体に接合する酸化物系セラミックス回路基板の接合方法において、上記加熱する工程は、１０６５～１０８５℃の間に加熱温度の極大値を有する第一加熱領域で積層体を加熱する工程と、次に１０００～１０５０℃の間に加熱温度の極小値を有する第二加熱領域で積層体を加熱する工程と、さらに１０６５～１１２０℃の間に加熱温度の極大値を有する第三加熱領域で積層体を加熱して接合体を形成する工程とを有し、その後接合体を冷却領域で冷却することを特徴とするものである。
　また、上記酸化物系セラミックス回路基板の製造方法において、前記加熱工程は、銅板を配置した酸化物系セラミックス基板をトレイ上に載置し、搬送速度（ベルトスピード）が７０～２７０ｍｍ／分のベルトコンベアでトレイを搬送しながら連続して各加熱工程を行うベルト炉を使用して実施することが好ましい。また、前記トレイがニッケル合金から成ることが好ましい。また、前記銅板はプレス加工により複数の回路要素とそれらの回路要素を繋ぐブリッジ部とを形成した回路構造を有し、前記銅板と酸化物系セラミックス基板とを接合後に、上記ブリッジ部を除去することが好ましい。また、前記酸化物系セラミックス基板と銅板とを接合後にエッチング工程により回路構造を形成することが好ましい。また、前記加熱工程は、窒素ガス雰囲気中で実施することが好ましい。
　また、前記ベルト炉は、入り口カーテンの窒素流量（Ａ）と出口カーテンの窒素流量（Ｂ）の比Ａ／Ｂが０．２以下に制御された窒素ガス雰囲気を備えることが好ましい
　また、前記酸化物系セラミックス基板は、アルミナ焼結体、アルミナとジルコニアとの混合焼結体のいずれか１種から成ることが好ましい。また、前記銅板の酸化物系セラミックス基板に配置される面に酸化膜を設ける工程を有することが好ましい。さらに、前記銅板の接合強度が９．５ｋｇｆ／ｃｍ以上であることが好ましい。また、前記銅板中の炭素含有率が０．１～１．０質量％であることが好ましい。 The method for producing an oxide-based ceramic circuit board according to the present invention includes a step of forming a laminate by placing a copper plate on an oxide-based ceramic substrate, and a step of heating the obtained laminate. In the method for joining an oxide-based ceramic circuit board in which a ceramic substrate and a copper plate are joined together, the heating step comprises heating the laminate in a first heating region having a maximum heating temperature between 1065 and 1085 ° C. A step of heating the laminate in a second heating region having a minimum heating temperature between 1000 and 1050 ° C., and a third having a maximum heating temperature between 1065 and 1120 ° C. And heating the laminated body in the heating region to form a joined body, and thereafter cooling the joined body in the cooling region.
In the method for manufacturing an oxide-based ceramic circuit board, the heating step includes placing an oxide-based ceramic substrate on which a copper plate is disposed on a tray, and a belt having a conveyance speed (belt speed) of 70 to 270 mm / min. It is preferable to carry out using a belt furnace that performs each heating step continuously while conveying the tray with a conveyor. The tray is preferably made of a nickel alloy. The copper plate has a circuit structure in which a plurality of circuit elements and a bridge portion connecting the circuit elements are formed by press working, and the bridge portion is removed after joining the copper plate and the oxide-based ceramic substrate. It is preferable. Moreover, it is preferable to form a circuit structure by an etching process after joining the oxide ceramic substrate and the copper plate. Moreover, it is preferable to implement the said heating process in nitrogen gas atmosphere.
In addition, the belt furnace preferably includes a nitrogen gas atmosphere in which a ratio A / B of the nitrogen flow rate (A) of the entrance curtain and the nitrogen flow rate (B) of the exit curtain is controlled to be 0.2 or less. The physical ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia. Moreover, it is preferable to have the process of providing an oxide film in the surface arrange | positioned at the oxide type ceramic substrate of the said copper plate. Furthermore, the bonding strength of the copper plate is preferably 9.5 kgf / cm or more. The carbon content in the copper plate is preferably 0.1 to 1.0% by mass.
　また、本発明の酸化物系セラミックス回路基板は、銅板と酸化物系セラミックス基板とを直接接合法により接合した酸化物系セラミックス回路基板において、銅板を剥がしたとき、銅板の酸化物系セラミックス基板との接合面側の銅の面積率が単位面積３０００μｍ×３０００μｍ当り６０％以下であり、上記銅板の接合強度が９．５ｋｇｆ／ｃｍ以上であることを特徴とするものである。
　また、上記酸化物系セラミックス回路基板において、前記酸化物系セラミックス基板が、アルミナ焼結体、アルミナとジルコニアとの混合焼結体のいずれか１種から成ることが好ましい。また、前記酸化物系セラミックス回路基板を、温度－４０℃で３０分間保持し、次に温度２５℃で１０分間保持し、次に温度１２５℃で３０分間保持し、次に温度２５℃で１０分間保持する加熱工程を１サイクルとする熱サイクル試験（ＴＣＴ）を１００サイクル実施した後においても、酸化物系セラミックス基板にクラックが発生しないことが好ましい。
　また、前記酸化物系セラミックス基板の密度が３．６０～３．７９ｇ／ｃｍ３であることが好ましい。また、前記酸化物系セラミックス回路基板を、温度－４０℃で３０分間保持し、次に温度２５℃で１０分間保持し、次に温度１２５℃で３０分間保持し、次に温度２５℃で１０分間保持する加熱工程を１サイクルとする熱サイクル試験（ＴＣＴ）を１００サイクル実施した後において、前記銅板の接合強度が６．５ｋｇｆ／ｃｍ以上であることが好ましい。
　また、前記銅板の厚さが０．２～０．５ｍｍであることが好ましい。また、前記酸化物系セラミックス基板の表面粗さＲａが０．１～０．７μｍであることが好ましい。また、前記銅板の結晶粒界に酸素が存在することが好ましい。また、前記銅板の平均結晶粒径が３００～８００μｍであることが好ましい。また、前記銅板の炭素含有率が０．１～１．０質量％であることが好ましい。 The oxide-based ceramic circuit board of the present invention is an oxide-based ceramic circuit board in which a copper plate and an oxide-based ceramic substrate are bonded by a direct bonding method. The area ratio of copper on the bonding surface side is 60% or less per unit area of 3000 μm × 3000 μm, and the bonding strength of the copper plate is 9.5 kgf / cm or more.
In the oxide ceramic circuit board, the oxide ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia. The oxide-based ceramic circuit board is held at a temperature of −40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C. for 30 minutes, and then at a temperature of 25 ° C. for 10 minutes. Even after 100 cycles of a thermal cycle test (TCT) in which the heating process for 1 minute is one cycle, it is preferable that no cracks occur in the oxide-based ceramic substrate.
The oxide ceramic substrate preferably has a density of 3.60 to 3.79 g / cm 3 . The oxide-based ceramic circuit board is held at a temperature of −40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C. for 30 minutes, and then at a temperature of 25 ° C. for 10 minutes. After 100 cycles of a heat cycle test (TCT) in which the heating step for 1 minute is one cycle, the copper plate preferably has a bonding strength of 6.5 kgf / cm or more.
The copper plate preferably has a thickness of 0.2 to 0.5 mm. The surface roughness Ra of the oxide ceramic substrate is preferably 0.1 to 0.7 μm. Moreover, it is preferable that oxygen exists in the crystal grain boundary of the said copper plate. The average crystal grain size of the copper plate is preferably 300 to 800 μm. The carbon content of the copper plate is preferably 0.1 to 1.0% by mass.
　本発明に係る酸化物系セラミックス回路基板の製造方法によれば、所定の第一加熱領域、第二加熱領域、第三加熱領域で加熱工程を実施していることから共晶による接合反応を安定化させることができるので、セラミックス回路基板の製造歩留りを向上させることができる。また、本発明に係る酸化物系セラミックス回路基板は、接合強度が高く、ＴＣＴ特性を向上させることができる。 According to the method of manufacturing an oxide-based ceramic circuit board according to the present invention, since the heating process is performed in the predetermined first heating region, second heating region, and third heating region, the eutectic bonding reaction is stabilized. Therefore, the manufacturing yield of the ceramic circuit board can be improved. In addition, the oxide-based ceramic circuit board according to the present invention has high bonding strength and can improve TCT characteristics.
本発明に係る酸化物系セラミックス回路基板の一実施例の構成を示す断面図である。It is sectional drawing which shows the structure of one Example of the oxide type ceramic circuit board based on this invention. 本発明に係る酸化物系セラミックス回路基板の製造方法の一実施例を示す断面図である。It is sectional drawing which shows one Example of the manufacturing method of the oxide type ceramic circuit board based on this invention. 本発明に係る酸化物系セラミックス回路基板の製造方法における温度プロファイルの一例を示すグラフである。It is a graph which shows an example of the temperature profile in the manufacturing method of the oxide type ceramic circuit board which concerns on this invention. 本発明に係る酸化物系セラミックス回路基板の製造方法の他の実施例を示す断面図である。It is sectional drawing which shows the other Example of the manufacturing method of the oxide type ceramic circuit board based on this invention.
　本実施形態に係る酸化物系セラミックス回路基板の製造方法は、酸化物系セラミックス基板上に銅板を配置して積層体を形成する工程と、得られた積層体を加熱する工程とにより、酸化物系セラミックス基板と銅板とを一体に接合する酸化物系セラミックス回路基板の接合方法において、上記加熱する工程は、１０６５～１０８５℃の間に加熱温度の極大値を有する第一加熱領域で積層体を加熱する工程と、次に１０００～１０５０℃の間に加熱温度の極小値を有する第二加熱領域で積層体を加熱する工程と、さらに１０６５～１１２０℃の間に加熱温度の極大値を有する第三加熱領域で積層体を加熱して接合体を形成する工程とを有し、その後接合体を冷却領域で冷却することを特徴とするものである。
　図１に酸化物系セラミックス回路基板の一構成例を示す。図中、符号１は酸化物系セラミックス回路基板であり、符号１１は酸化物系セラミックス基板であり、符号１２は銅回路板（回路用銅板）であり、符号１３は裏金属板（裏銅板）である。 The method for manufacturing an oxide-based ceramic circuit board according to this embodiment includes an oxide ceramic substrate including a step of forming a laminate by placing a copper plate on an oxide-based ceramic substrate and a step of heating the obtained laminate. In the method of joining an oxide ceramic circuit board in which a ceramic ceramic substrate and a copper plate are joined together, the heating step includes the step of heating the laminate in a first heating region having a maximum heating temperature between 1065 and 1085 ° C. A step of heating, a step of heating the laminate in a second heating region having a minimum value of the heating temperature between 1000 and 1050 ° C., and a second value having a maximum value of the heating temperature between 1065 and 1120 ° C. Forming a joined body by heating the laminated body in three heating regions, and then cooling the joined body in a cooling region.
FIG. 1 shows an example of the configuration of an oxide ceramic circuit board. In the figure, reference numeral 1 is an oxide ceramic circuit board, reference numeral 11 is an oxide ceramic board, reference numeral 12 is a copper circuit board (copper board for circuit), and reference numeral 13 is a back metal plate (back copper board). It is.
　まず、酸化物系セラミックス基板１１は、アルミナ焼結体、アルミナとジルコニアの混合焼結体のいずれか１種であることが好ましい。アルミナ焼結体は、Ｓｉ成分、Ｃａ成分、Ｍｇ成分、Ｎａ成分などの焼結助剤を８質量％以下含有してもよい。また、アルミナとジルコニアの混合焼結体は、ジルコニアを１０～９０質量％、残部アルミナの焼結体であることが好ましい。なお、必要に応じ、焼結助剤を８質量％以下含有させてもよい。
　また、銅板は、酸素を１００～１０００質量ｐｐｍ含有するタフピッチ電解銅から成る銅板を使用することが好ましい。また、酸素含有量が１００質量ｐｐｍ未満の銅板を用いる場合は、銅板の酸化物系セラミックス基板との接合面側に酸化銅膜を形成することが好ましい。酸化銅膜の形成方法は、銅板を熱処理して直接酸化する方法や酸化銅粉末のペーストを塗布する方法などが挙げられる。具体的には、銅板を大気中において温度１５０～３６０℃の範囲にて２０～１２０秒間加熱する表面酸化処理を実施することによって形成することができる。
　ここで、酸化銅膜の厚さが１μｍ未満の場合は、Ｃｕ－Ｏ共晶の発生量が少なくなるため、基板と銅回路板との未接合部分が多く、接合強度を向上させる効果は少ない。一方、酸化銅層の厚さが１０μｍを超えるように過大にしても、接合強度の改善効果が少なく、却って銅回路板の導電特性を阻害することになる。したがって、銅回路板表面に形成する酸化銅層の厚さは１～１０μｍの範囲が好ましい。そして同様の理由により２～５μｍ の範囲がより望ましい。酸化銅粉末のペーストを使う場合は、平均粒径１～５μｍの酸化銅粉末を使用し、厚さ１～１０μｍの酸化銅膜を形成した後、乾燥または熱処理する。
　また、銅板は炭素を０．１～１．０質量％含有することが好ましい。炭素は脱酸剤として機能するため、銅板（タフピッチ銅または無酸素銅）中の酸素を銅板表面に移動させる効果を得ることができる。銅板表面に移動した酸素は直接接合法を行う際のＣｕ－Ｏ共晶を形成するのに活用することができる。炭素含有量が０．１質量％未満では含有の効果がなく、１．０質量％を超えると炭素含有量が増え過ぎて銅板の導電性を低下させる。 First, the oxide-based ceramic substrate 11 is preferably one of an alumina sintered body and a mixed sintered body of alumina and zirconia. The alumina sintered body may contain 8% by mass or less of a sintering aid such as an Si component, a Ca component, an Mg component, or an Na component. The mixed sintered body of alumina and zirconia is preferably a sintered body of 10 to 90% by mass of zirconia and the remaining alumina. In addition, you may contain 8 mass% or less of sintering adjuvant as needed.
The copper plate is preferably a copper plate made of tough pitch electrolytic copper containing 100 to 1000 ppm by mass of oxygen. Moreover, when using the copper plate whose oxygen content is less than 100 mass ppm, it is preferable to form a copper oxide film on the bonding surface side of the copper plate with the oxide ceramic substrate. Examples of the method of forming the copper oxide film include a method of directly oxidizing the copper plate by heat treatment, a method of applying a paste of copper oxide powder, and the like. Specifically, it can be formed by performing a surface oxidation treatment in which a copper plate is heated in the atmosphere at a temperature of 150 to 360 ° C. for 20 to 120 seconds.
Here, when the thickness of the copper oxide film is less than 1 μm, since the amount of Cu—O eutectic generated is small, there are many unbonded portions between the substrate and the copper circuit board, and the effect of improving the bonding strength is small. . On the other hand, even if the thickness of the copper oxide layer is too large so as to exceed 10 μm, the effect of improving the bonding strength is small and the conductivity characteristics of the copper circuit board are hindered. Therefore, the thickness of the copper oxide layer formed on the copper circuit board surface is preferably in the range of 1 to 10 μm. For the same reason, the range of 2 to 5 μm is more desirable. When a copper oxide powder paste is used, a copper oxide powder having an average particle diameter of 1 to 5 μm is used, and a copper oxide film having a thickness of 1 to 10 μm is formed, followed by drying or heat treatment.
The copper plate preferably contains 0.1 to 1.0% by mass of carbon. Since carbon functions as a deoxidizer, it is possible to obtain an effect of moving oxygen in the copper plate (tough pitch copper or oxygen-free copper) to the copper plate surface. Oxygen that has migrated to the copper plate surface can be used to form a Cu—O eutectic during direct bonding. If the carbon content is less than 0.1% by mass, there is no effect of inclusion. If the carbon content exceeds 1.0% by mass, the carbon content is excessively increased and the conductivity of the copper plate is lowered.
　本発明で用いる接合方法は、直接接合法（ＤＢＣ：ｄｉｌｅｃｔ　ｂｏｎｄｉｎｇ　ｃｏｐｐｅｒ）である。直接接合法は、酸化物系セラミックス基板１１上に、銅回路板１２、裏銅板１３を接触配置して加熱し、接合界面にＣｕ－Ｃｕ２Ｏ ，Ｃｕ－Ｏ等の共晶液相を生成させて、この液相により酸化物系セラミックス基板との濡れ性を高め、次いで、この液相を冷却固化させることにより、酸化物系セラミックス基板と銅板とを直接接合するものである。銅と酸素との共晶を利用することから、接合面に銅と酸素とが存在する形態にする必要がある。
　銅と酸素の共晶液相の生成は１０６５℃以上の温度で起きる。一方、銅の融点が１０８３℃であるため、過度に温度が高いと銅板が溶解してしまう。そのため、１０６５～１０８５℃の温度範囲で接合する。従来の直接接合法では温度１０６５～１０８５℃で熱処理した後は、そのまま常温に戻す冷却工程に入っていた。 The joining method used in the present invention is a direct joining method (DBC). In the direct bonding method, the copper circuit board 12 and the back copper board 13 are placed in contact with each other on the oxide ceramic substrate 11 and heated to produce a eutectic liquid phase such as Cu—Cu 2 O and Cu—O at the bonding interface. Thus, the wettability with the oxide ceramic substrate is increased by this liquid phase, and then the liquid ceramic phase is cooled and solidified to directly bond the oxide ceramic substrate and the copper plate. Since a eutectic of copper and oxygen is used, it is necessary to have a form in which copper and oxygen exist on the joint surface.
The formation of the eutectic liquid phase of copper and oxygen occurs at a temperature of 1065 ° C. or higher. On the other hand, since the melting point of copper is 1083 ° C., if the temperature is excessively high, the copper plate is dissolved. Therefore, bonding is performed in a temperature range of 1065 to 1085 ° C. In the conventional direct bonding method, after heat treatment at a temperature of 1065 to 1085 ° C., a cooling process for returning to normal temperature has been started.
　それに対して、本発明の酸化物系セラミックス回路基板の製造方法では、前記加熱する工程は、１０６５～１０８５℃の間に極大値をもつ第一加熱領域、次に１０００～１０５０℃の間に極小値をもつ第二加熱領域、さらには１０６５～１１２０℃の間に極大値をもつ第三加熱領域を有し、その後冷却領域となることとした。
　図２に本発明に係る酸化物系セラミックス回路基板の製造方法の一例を示す。図２中、符号１は酸化物系セラミックス回路基板であり、２はトレイであり、３はベルトコンベアである。トレイ２上に載置された酸化物系セラミックス回路基板１の積層体は、図中の矢印で示すように、ベルトコンベア３によって、向かって左から右に搬送される。
　図２では、接合前の酸化物系セラミックス回路基板１を配置したトレイ２をベルトコンベア３上に配置し、ベルトコンベア３にてトレイ２を搬送するベルト炉６を例示している。なお、本発明では後述する第一加熱領域、第二加熱領域、第三加熱領域を具備している限り、上記ベルト炉６に限定されるものではない。 On the other hand, in the method for manufacturing an oxide-based ceramic circuit board according to the present invention, the heating step includes a first heating region having a maximum value between 1065 and 1085 ° C., and then a minimum between 1000 and 1050 ° C. A second heating region having a value, a third heating region having a maximum value between 1065 to 1120 ° C., and a cooling region thereafter.
FIG. 2 shows an example of a method for manufacturing an oxide-based ceramic circuit board according to the present invention. In FIG. 2, reference numeral 1 is an oxide-based ceramic circuit board, 2 is a tray, and 3 is a belt conveyor. The laminated body of the oxide-based ceramic circuit board 1 placed on the tray 2 is conveyed from the left to the right by the belt conveyor 3 as indicated by arrows in the drawing.
FIG. 2 illustrates a belt furnace 6 in which the tray 2 on which the oxide-based ceramic circuit board 1 before bonding is disposed is disposed on the belt conveyor 3 and the tray 2 is conveyed by the belt conveyor 3. In the present invention, the belt furnace 6 is not limited as long as the first heating region, the second heating region, and the third heating region described later are provided.
　まず、加熱する工程では、１０６５～１０８５℃の温度範囲内で加熱温度の極大値を持つ第一加熱領域を形成する。第一加熱領域の形成は、第一加熱領域に相当する部分にあるヒータ（図示せず）の出力温度を調整することにより形成できる。
　上記第一加熱領域の後（２次側）に、１０００～１０５０℃の温度範囲内に加熱温度の極小値を有する第二加熱領域を形成し、その次に１０６５～１１２０℃の温度範囲内に加熱温度の極大値を有する第三加熱領域を形成して冷却工程へと続いていく。温度調節に関しては、それぞれの領域にあるヒータの出力温度を変えることにより調整できる。上記第一加熱領域、第二加熱領域、第三加熱領域における加熱工程を連続的に実施することが必要である。そのためにはベルト炉６で搬送しながら、それぞれの温度領域を通過させる方法が好ましい。 First, in the heating step, a first heating region having a maximum heating temperature within a temperature range of 1065 to 1085 ° C. is formed. The first heating region can be formed by adjusting the output temperature of a heater (not shown) in the portion corresponding to the first heating region.
After the first heating region (secondary side), a second heating region having a minimum heating temperature within a temperature range of 1000 to 1050 ° C. is formed, and then within a temperature range of 1065 to 1120 ° C. A third heating region having a maximum value of the heating temperature is formed and the cooling process is continued. The temperature can be adjusted by changing the output temperature of the heater in each region. It is necessary to continuously perform the heating process in the first heating region, the second heating region, and the third heating region. For this purpose, a method in which each temperature region is passed while being conveyed in the belt furnace 6 is preferable.
　図３に本発明に係る酸化物系セラミックス回路基板の製造方法における加熱工程での温度プロファイルの一例を示す。図３に示したように銅と酸素との共晶反応が生起する１０６５～１０８５℃の温度範囲（第一加熱領域）に積層体を加熱した後、共晶反応が生起しない１０００～１０６４℃の温度範囲（第二加熱領域）に下げて積層体の加熱工程を実施し、再度、共晶反応が生起する１０６５～１１２０℃の温度範囲（第三加熱領域）に上げて加熱工程を実施する。
　このように温度プロファイルとして、加熱温度を上げて・下げて・上げて各加熱工程を連続して実施するのである。なお、図３では温度プロファイルの線図が曲線状に変化する状態を示したが、極大値または極小値となる一定温度で保持するように設定してもよい。
　上記の第一加熱領域にて銅と酸素との共晶反応が生起したとき、銅板中（または銅板表面）に含有されている酸素は共晶反応に使用されたり、銅板から外に放出されたりする。しかしながら、銅板中の酸素を全て共晶反応または外に放出することは困難であり、その一部は銅板中に残存する。共晶反応直後に冷却工程に入ると残存した酸素は銅板中で樹枝状結晶（デンドライト：ｄｅｎｄｒｉｔｅ）が形成されてしまう。この樹枝状結晶が存在すると接合強度が低下する。また、銅板表面のめっきや半田との濡れ性が低下する。 FIG. 3 shows an example of a temperature profile in the heating step in the method for manufacturing an oxide-based ceramic circuit board according to the present invention. As shown in FIG. 3, after heating the laminate to a temperature range of 1065 to 1085 ° C. where the eutectic reaction between copper and oxygen occurs (first heating region), 1000 to 1064 ° C. where no eutectic reaction occurs. The laminated body is heated to a temperature range (second heating region) and then heated again to a temperature range of 1065 to 1120 ° C. (third heating region) where a eutectic reaction occurs.
As described above, as the temperature profile, the heating temperature is increased, decreased, or increased, and each heating step is continuously performed. Although FIG. 3 shows a state in which the diagram of the temperature profile changes in a curved shape, the temperature profile may be set so as to be held at a constant temperature at which the maximum value or the minimum value is obtained.
When a eutectic reaction between copper and oxygen occurs in the first heating zone, oxygen contained in the copper plate (or the copper plate surface) is used for the eutectic reaction or released out of the copper plate. To do. However, it is difficult to release all the oxygen in the copper plate to the eutectic reaction or to the outside, and part of it remains in the copper plate. When entering the cooling step immediately after the eutectic reaction, the remaining oxygen forms dendrites in the copper plate. If this dendritic crystal is present, the bonding strength decreases. Moreover, the wettability with the plating and soldering of the copper plate surface decreases.
　そのため、第二加熱領域を設け共晶反応以下の温度である１０００～１０６４℃という低い温度で加熱することにより共晶反応を安定化させ、その後、第三加熱領域にて１０６５～１１２０℃の温度範囲で再加熱することにより、残存した樹枝状結晶を除去することができる。つまりは、樹枝状結晶を形成していた酸素を銅板から放出することができるのである。
　また、第二加熱領域は、１０００℃未満であると温度が下がり過ぎて第三加熱領域で樹枝状結晶の除去が十分行われない。好ましくは、加熱温度範囲は１０２０～１０５０℃である。
　また、第三加熱領域は、１１２０℃を超えると銅板の溶解（変形）を招くので好ましくない。さらに好ましい加熱温度範囲は１０７０～１０９０℃である。また、第三加熱領域にて樹枝状結晶を形成する酸素を除去するためには、第一加熱領域の加熱温度よりも第三加熱領域の温度が高い方が好ましい。 Therefore, the eutectic reaction is stabilized by providing a second heating region and heating at a temperature as low as 1000 to 1064 ° C., which is the temperature below the eutectic reaction, and thereafter, a temperature of 1065 to 1120 ° C. in the third heating region. Residual dendritic crystals can be removed by reheating in the range. In other words, the oxygen that has formed dendritic crystals can be released from the copper plate.
Further, if the temperature of the second heating region is lower than 1000 ° C., the temperature is excessively lowered, and the dendritic crystals are not sufficiently removed in the third heating region. Preferably, the heating temperature range is 1020 to 1050 ° C.
Moreover, since a 3rd heating area | region will cause melt | dissolution (deformation) of a copper plate when it exceeds 1120 degreeC, it is not preferable. A more preferable heating temperature range is 1070 to 1090 ° C. In order to remove oxygen that forms dendritic crystals in the third heating region, it is preferable that the temperature of the third heating region is higher than the heating temperature of the first heating region.
　また、加熱工程は、銅板を配置した酸化物系セラミックス基板（積層体）をトレイ上に載置し、ベルトスピードが７０～２７０ｍｍ／分のベルトコンベアでトレイを搬送しながら連続して各加熱工程を実施するベルト炉を用いることが好ましい。ベルトスピードを制御することにより、熱処理時間を調整することができる。
　ベルトスピードが７０ｍｍ／分より小さいと、単位時間当たりの処理数（タクト）が減少し、また特に第一加熱領域における過剰な熱処理によりデンドライト生成がより促進されて、第二加熱領域および第三加熱領域で除去しきれなくなる。
　一方、ベルトスピードが２７０ｍｍ／分より大きいと、第一・第三加熱領域での接合が不十分となって銅板剥がれなどの不良を招くおそれがある。ベルトスピードは好ましくは１００～２２０ｍｍ／分の範囲である。また、前述の搬送速度を使って連続搬送するときは、第一加熱領域、第二加熱領域、第三加熱領域はそれぞれ３００～２０００ｍｍの運搬距離であることが好ましい。 In addition, the heating process is performed by continuously placing an oxide ceramic substrate (laminated body) on which a copper plate is placed on a tray, and continuously conveying the tray with a belt conveyor having a belt speed of 70 to 270 mm / min. It is preferable to use a belt furnace that implements the above. The heat treatment time can be adjusted by controlling the belt speed.
When the belt speed is less than 70 mm / min, the number of treatments (tact) per unit time is reduced, and in particular, excessive heat treatment in the first heating area further promotes dendrite generation, and the second heating area and the third heating area. It cannot be removed in the area.
On the other hand, when the belt speed is higher than 270 mm / min, the joining in the first and third heating regions is insufficient, and there is a risk of causing defects such as peeling of the copper plate. The belt speed is preferably in the range of 100 to 220 mm / min. Further, when continuously transporting using the above-described transport speed, it is preferable that the first heating region, the second heating region, and the third heating region each have a transport distance of 300 to 2000 mm.
　また、酸化物系セラミックス回路基板（積層体）を搬送するトレイがニッケル合金で構成されることが好ましい。上記トレイは、銅板または酸化物系セラミックス基板と接した状態で熱処理炉（ベルト炉）に搬送される。このため、直接接合法で用いる温度１０６５～１１２０℃付近で銅や酸化物系セラミックス基板と反応しない材料であることが必要である。
　酸化物系セラミックス回路基板は両面に銅板を配置し接合した方が反り防止に有効である。そのため、熱処理温度で銅板と反応せず、その上で熱により変形しない材料であることが望まれる。
　このような材料としてニッケル合金があり、特にクロムと鉄を所定量含有したインコネルが好ましい。インコネルには、インコネル６００（質量％でＮｉ７６．０、Ｃｒ１５．５、Ｆｅ８．０）、インコネル６０１（質量％でＮｉ６０．５、Ｃｒ２３．０、Ｆｅ１４．４、Ａｌ１．４）が代表として挙げられる。これ以外にもインコネル６２５、インコネル７１８、インコネルＸ７５０が挙げられる。インコネルは耐熱合金として使われており、銅板と反応せず、熱変形しないので好ましい。また、銅板との反応をより効果的に防止するために、インコネル製トレイの表面に湿水素処理を施すことが効果的である。 Moreover, it is preferable that the tray which conveys an oxide type ceramic circuit board (laminated body) is comprised with a nickel alloy. The tray is conveyed to a heat treatment furnace (belt furnace) in contact with a copper plate or an oxide ceramic substrate. For this reason, it is necessary that the material does not react with copper or an oxide-based ceramic substrate at a temperature of about 1065 to 1120 ° C. used in the direct bonding method.
The oxide ceramic circuit board is more effective in preventing warpage if a copper plate is disposed on both sides and bonded. Therefore, it is desired that the material does not react with the copper plate at the heat treatment temperature and does not deform by heat.
There is a nickel alloy as such a material, and inconel containing a predetermined amount of chromium and iron is particularly preferable. Typical examples of Inconel include Inconel 600 (Ni 76.0, Cr 15.5, Fe 8.0 by mass%) and Inconel 601 (Ni 60.5, Cr 23.0, Fe 14.4, Al 1.4 by mass%). . In addition, Inconel 625, Inconel 718, and Inconel X750 can be used. Inconel is used as a heat-resistant alloy and is preferable because it does not react with the copper plate and does not thermally deform. In order to more effectively prevent the reaction with the copper plate, it is effective to perform wet hydrogen treatment on the surface of the Inconel tray.
　また、前記加熱工程は、窒素ガス雰囲気中で実施することが好ましい。直接接合法は、銅と酸素との共晶反応を利用することから、加熱工程を実施する雰囲気中に必要以上に酸素が存在しないことが好ましい。このため、加熱接合工程は不活性雰囲気中で実施することが好ましい。
　不活性雰囲気としては、窒素ガス、アルゴンガスが挙げられる。この中で窒素ガスの方が経済的であるため、窒素ガスを使うことが好ましい。また、窒素ガスの純度は９９．９％以上、さらには９９．９９％以上の高純度ガスであることが好ましい。 Moreover, it is preferable to implement the said heating process in nitrogen gas atmosphere. Since the direct bonding method utilizes a eutectic reaction between copper and oxygen, it is preferable that oxygen is not present more than necessary in the atmosphere in which the heating step is performed. For this reason, it is preferable to implement a heat joining process in inert atmosphere.
Examples of the inert atmosphere include nitrogen gas and argon gas. Among these, since nitrogen gas is more economical, it is preferable to use nitrogen gas. The purity of the nitrogen gas is preferably a high purity gas of 99.9% or more, more preferably 99.99% or more.
　また、ベルト炉６は、入口カーテンの窒素流量（Ａ）と出口カーテンの窒素流量（Ｂ）の比Ａ／Ｂが０．２以下にコントロールされた窒素ガス雰囲気を備えることが好ましい。図４に、窒素流量を説明するためのベルト炉６の断面図を示す。図中、酸化物系セラミックス回路基板（積層体または接合体）１は、トレイ２上に載置された状態で、搬送ベルト（ベルトコンベア）３によって、搬入口（入口）４側から搬出口（出口）５側に所定の搬送速度で搬送される。
　ベルト炉６の搬入口４の近傍には、入口カーテンが設けられる一方、搬出口５の近傍には出口カーテンが設けられる。ここで、Ａは入り口カーテンの窒素流量を示し、Ｂは出口カーテンの窒素流量を示す。すなわち、搬入口４の近傍には、窒素流量（Ａ）で流出する窒素ガスが流れている。また、搬出口５の近傍には窒素流量（Ｂ）で流出する窒素ガスが流れている。
　ここで、窒素流量（Ａ）／窒素流量（Ｂ）が０．２以下にコントロールすることが好ましい。窒素流量比Ａ／Ｂが０．２以下であるということは、窒素流量Ｂが窒素流量Ａの５倍以上大きな流量で流れていることを示す。このような関係であると、搬出口５から搬入口４方向に窒素ガスの流れが形成される。トレイ２の搬送方向に対して向い風（カウンターフロー）となることにより、加熱工程中（例えばベルト炉６内）に大気が残存しても窒素ガスで流して除去することができる。
　また、加熱工程中に銅回路板および裏銅板から放出される酸素を酸化物系セラミックス回路基板の近傍に滞在させない効果も発揮される。一方、窒素ガスが流れる方向が、トレイ２の搬送方向と同一であると、場合によってはベルト炉６内の酸素が酸化物系セラミックス回路基板１の周囲に滞留残存したままになるおそれもある。 The belt furnace 6 preferably includes a nitrogen gas atmosphere in which the ratio A / B of the nitrogen flow rate (A) of the entrance curtain and the nitrogen flow rate (B) of the exit curtain is controlled to 0.2 or less. FIG. 4 shows a cross-sectional view of the belt furnace 6 for explaining the nitrogen flow rate. In the drawing, an oxide-based ceramic circuit board (laminated body or bonded body) 1 is placed on a tray 2 and is transported from a carry-in port (inlet) 4 side to a carry-out port (belt conveyor) 3 by a carrying belt (belt conveyor) 3. It is transported to the exit 5 side at a predetermined transport speed.
An entrance curtain is provided near the carry-in port 4 of the belt furnace 6, while an exit curtain is provided near the carry-out port 5. Here, A indicates the nitrogen flow rate of the entrance curtain, and B indicates the nitrogen flow rate of the exit curtain. That is, nitrogen gas flowing out at a nitrogen flow rate (A) flows in the vicinity of the carry-in port 4. Also, nitrogen gas flowing out at a nitrogen flow rate (B) flows in the vicinity of the carry-out port 5.
Here, it is preferable to control the nitrogen flow rate (A) / nitrogen flow rate (B) to 0.2 or less. The nitrogen flow rate ratio A / B being 0.2 or less indicates that the nitrogen flow rate B is flowing at a flow rate that is at least five times greater than the nitrogen flow rate A. With such a relationship, a flow of nitrogen gas is formed from the carry-out port 5 toward the carry-in port 4. By using a wind (counter flow) that is directed toward the conveyance direction of the tray 2, even if air remains in the heating process (for example, in the belt furnace 6), it can be removed by flowing with nitrogen gas.
In addition, the effect of preventing oxygen released from the copper circuit board and the back copper board from staying in the vicinity of the oxide-based ceramic circuit board during the heating process is also exhibited. On the other hand, if the direction in which the nitrogen gas flows is the same as the transport direction of the tray 2, the oxygen in the belt furnace 6 may remain and remain around the oxide-based ceramic circuit board 1 in some cases.
　また、窒素流量（Ａ）は、２～２０リットル／分であることが好ましい。また、窒素流量（Ｂ）は、３０～１００リットル／分であることが好ましい。これらの範囲であれば、窒素流量の制御が実施し易い。また、搬入口４近傍の窒素流量が２リットル／分以上とすることによって、搬入口４から大気などの不純物やごみが混入することを防止する気流カーテンとして機能させることができる。同様に、搬出口５における窒素流量を３０リットル／分以上とすることにより、搬出口５から大気などの不純物やごみが混入することを効果的に防止することができる。
　また、不純物の混入を防止するという点に関して言えば、加熱した窒素ガスを流すことも有効である。つまり加熱することにより、窒素ガスに含まれる水分やベルト炉内にある水分を蒸発させる効果がある。窒素ガスの加熱温度としては、５０～１８０℃の範囲が好ましい。５０℃未満では窒素ガスを加熱する効果が十分でなく、１８０℃を超えるとこれ以上の効果が得られないだけでなくコストアップの要因となる。 The nitrogen flow rate (A) is preferably 2 to 20 liters / minute. The nitrogen flow rate (B) is preferably 30 to 100 liters / minute. Within these ranges, it is easy to control the nitrogen flow rate. Moreover, when the nitrogen flow rate in the vicinity of the carry-in port 4 is set to 2 liters / minute or more, it can function as an airflow curtain that prevents impurities such as the atmosphere and dust from entering from the carry-in port 4. Similarly, by setting the nitrogen flow rate at the carry-out port 5 to 30 liters / min or more, it is possible to effectively prevent impurities such as the atmosphere and dust from entering the carry-out port 5.
In terms of preventing impurities from entering, it is also effective to flow heated nitrogen gas. In other words, by heating, there is an effect of evaporating moisture contained in the nitrogen gas and moisture in the belt furnace. The heating temperature of nitrogen gas is preferably in the range of 50 to 180 ° C. If the temperature is less than 50 ° C., the effect of heating the nitrogen gas is not sufficient.
　次に銅板を銅回路板に加工する工程について説明する。前述の加熱工程（接合工程）において、予め回路形状に加工した銅板を配置して、そのまま接合する方法が望ましい。しかしながら、ベルト炉のように搬送しながら接合工程を行う製法では、搬送中に酸化物系セラミックス基板上で銅板のズレが生じる恐れがある。そのため、設置面積の大きな状態で酸化物系セラミックス基板に配置することが望ましい。
　銅板の設置面積を大きくする方法としては、次の方法がある。第１の方法は、銅板をプレス加工により複数の回路板要素と、それを相互に繋げるブリッジ部とを設けた回路構造を形成することである。個々の銅回路板要素をブリッジ部で繋げた構造とすることにより、個々には小さな銅回路板をブリッジ部で繋げて見かけ上は大きな設置面積を有する銅回路板とすることができる。
　また、第２の方法は、酸化物系セラミックス基板に銅板を配置し、接合後にエッチング工程により所定形状の回路構造を形成する方法である。 Next, the process of processing a copper plate into a copper circuit board will be described. In the heating step (bonding step) described above, a method of placing a copper plate that has been processed into a circuit shape in advance and bonding it as it is is desirable. However, in the manufacturing method in which the joining process is performed while being transported like a belt furnace, the copper plate may be displaced on the oxide ceramic substrate during transport. Therefore, it is desirable to arrange the oxide ceramic substrate with a large installation area.
There are the following methods for increasing the installation area of the copper plate. The first method is to form a circuit structure provided with a plurality of circuit board elements and a bridge portion for connecting them together by pressing a copper plate. By adopting a structure in which individual copper circuit board elements are connected by a bridge portion, a small copper circuit board can be individually connected by a bridge portion to make a copper circuit board having an apparently large installation area.
The second method is a method in which a copper plate is disposed on an oxide-based ceramic substrate, and a circuit structure having a predetermined shape is formed by an etching process after bonding.
　また、銅板（銅回路板および裏銅板）の位置ずれを防止する方法としては、樹脂バインダーを酸化物系セラミックス基板上に塗布し、その上に銅板を配置する方法が挙げられる。樹脂バインダーは加熱工程にて焼失するものであれば特に限定されるものではない。このような樹脂バインダーとしてはアクリルバインダー（例えばイソブチルメタアクリレートなど）が挙げられる。樹脂バインダーの塗布形状としては、直径１０ｍｍ以下のドット状に塗布することが好ましい。加熱工程により樹脂バインダーは焼失するが、銅板を配置する面の全面に塗布すると、焼失時に発生する二酸化炭素などの気体成分が酸化物系セラミックス基板と銅板との隙間から十分抜けきらずに、却って共晶反応の障害になる恐れがある。
　上記のようにして銅板の位置ずれを防止することにより、トレイのスピードが１５０ｍｍ／分以上である高速搬送を実施したとしても、位置ずれによる不良の発生を防止することができる。さらに位置ずれを防止することにより、トレイ上に１０個以上の多くの接合前の酸化物系セラミックス回路基板（積層体）を配置することが可能になるので、さらに量産性を向上させることができる。
　また、得られた酸化物系セラミックス回路基板の銅板表面にニッケルめっきを施してもよい。以上のような本発明の製造方法によって得られた酸化物系セラミックス回路基板では、銅板の接合強度を９．５ｋｇｆ／ｃｍ以上とすることができる。 Moreover, as a method of preventing the displacement of the copper plates (copper circuit plate and back copper plate), there is a method in which a resin binder is applied on an oxide ceramic substrate and a copper plate is disposed thereon. The resin binder is not particularly limited as long as it is burned off in the heating step. Examples of such a resin binder include an acrylic binder (for example, isobutyl methacrylate). The resin binder is preferably applied in the form of dots having a diameter of 10 mm or less. The resin binder is burned away by the heating process, but if it is applied to the entire surface on which the copper plate is placed, gas components such as carbon dioxide generated at the time of burning are not fully removed from the gap between the oxide-based ceramic substrate and the copper plate. There is a risk of hindrance to the crystal reaction.
By preventing the displacement of the copper plate as described above, it is possible to prevent the occurrence of a defect due to the displacement even if the tray speed is 150 mm / min or higher. Further, by preventing misalignment, it becomes possible to dispose 10 or more oxide-based ceramic circuit boards (laminated bodies) before bonding on the tray, so that mass productivity can be further improved. .
Moreover, you may nickel-plat on the copper plate surface of the obtained oxide type ceramic circuit board. In the oxide-based ceramic circuit board obtained by the manufacturing method of the present invention as described above, the bonding strength of the copper plate can be set to 9.5 kgf / cm or more.
　次に、本実施形態に係る酸化物系セラミックス回路基板について説明する。本実施形態に係る酸化物系セラミックス回路基板は、本発明に係る酸化物系セラミックス回路基板の製造方法で得られることを基本とするが、同様の構成を具備するものであればその製造方法は特に限定されるものではない。以下に本実施形態に係る発明の酸化物系セラミックス回路基板の構成について説明する。
　本実施形態に係る酸化物系セラミックス回路基板は、銅板と酸化物系セラミックス基板とを直接接合法により接合した酸化物系セラミックス回路基板において、銅板を剥がしたとき、銅板の酸化物系セラミックス基板との接合面側の銅の面積率が単位面積３０００μｍ×３０００μｍ当り６０％以下であり、銅板の接合強度が９．５ｋｇｆ／ｃｍ以上であることを特徴とするものである。
　まず、酸化物系セラミックス基板は、アルミナ焼結体、アルミナとジルコニアとの混合焼結体のいずれか１種から成ることが好ましい。アルミナ焼結体は、Ｓｉ成分、Ｃａ成分、Ｍｇ成分、Ｎａ成分などの焼結助剤を８質量％以下含有してもよい。また、アルミナとジルコニアの混合焼結体は、ジルコニアを１０～９０質量％、残部アルミナの焼結体であることが好ましい。なお、必要に応じ、焼結助剤を８質量％以下含有させてもよい。
　また、酸化物系セラミックス基板の密度が３．６０～３．７９ｇ／ｃｍ３であることが好ましい。密度が３．６０ｇ／ｃｍ３未満ではセラミックス基板内のポアが多すぎて基板の強度および熱伝導率が低下する。また、基板表面にポアが多いと、銅板との直接接合を行った際に未接合部が多くなり、接合強度が低下する。一方、密度が３．７９ｇ／ｃｍ３を超えて大きいと、却ってセラミックス基板の製造コストが上昇するので好ましくない。また、酸化物系セラミックス基板の厚さは０．３～１．２ｍｍであることが好ましい。 Next, the oxide ceramic circuit board according to the present embodiment will be described. The oxide-based ceramic circuit board according to the present embodiment is basically obtained by the method for manufacturing an oxide-based ceramic circuit board according to the present invention. It is not particularly limited. The structure of the oxide ceramic circuit board according to the present embodiment will be described below.
The oxide-based ceramic circuit board according to the present embodiment includes an oxide-based ceramic circuit board obtained by bonding a copper plate and an oxide-based ceramic substrate by a direct bonding method. The area ratio of copper on the bonding surface side is 60% or less per unit area of 3000 μm × 3000 μm, and the bonding strength of the copper plate is 9.5 kgf / cm or more.
First, the oxide-based ceramic substrate is preferably made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia. The alumina sintered body may contain 8% by mass or less of a sintering aid such as an Si component, a Ca component, an Mg component, or an Na component. The mixed sintered body of alumina and zirconia is preferably a sintered body of 10 to 90% by mass of zirconia and the remaining alumina. In addition, you may contain 8 mass% or less of sintering adjuvant as needed.
The density of the oxide-based ceramic substrate is preferably 3.60 to 3.79 g / cm 3 . When the density is less than 3.60 g / cm 3 , there are too many pores in the ceramic substrate, and the strength and thermal conductivity of the substrate decrease. Moreover, when there are many pores on the surface of the substrate, unbonded portions increase when direct bonding with the copper plate is performed, and the bonding strength decreases. On the other hand, if the density is larger than 3.79 g / cm 3 , the manufacturing cost of the ceramic substrate increases on the contrary, such being undesirable. The thickness of the oxide-based ceramic substrate is preferably 0.3 to 1.2 mm.
　また、銅板の構成材としては、酸素を所定量含有したタフピッチ銅を使用しても良いが、酸素含有量が少ない銅板でも良い。また、銅板の厚さは０．２～０．５ｍｍであることが好ましい。酸化物系セラミックス基板の厚さを０．３～１．２ｍｍの範囲にする一方、銅板の厚さを０．２～０．５ｍｍとすることにより酸化物系セラミックス基板と銅板との熱膨張差のバランスがとれて耐熱サイクル試験（ＴＣＴ試験）での耐久性が向上する。
　また、銅板は炭素を０．１～１．０質量％含有することが好ましい。炭素は脱酸剤として機能するため、銅板（タフピッチ銅または無酸素銅）中の酸素を銅板表面に移動させる効果を得ることができる。銅板表面に移動した酸素は直接接合法を実施する際のＣｕ－Ｏ共晶を形成するために活用することができる。炭素含有量が０．１質量％未満では、含有の効果が無い一方、１．０質量％を超えると炭素含有量が増え過ぎて銅板の導電性を低下させる。
　また、直接接合法を実施するに際して、酸化物系セラミックス基板の表面粗さがＲａで０．１～０．７μｍであることが好ましい。表面粗さＲａが０．１μｍ未満では、精度が高い表面研磨が必要になりコストアップの要因となる。また、表面粗さＲａが０．７μｍを超えると、表面が粗過ぎて銅板と酸化物系セラミックス基板との間に隙間ができて共晶反応が十分に進行しないおそれがある。
　このような酸化物系セラミックス基板を使用して酸化物系セラミックス回路基板を形成すると、接合した銅板を剥がした時の、銅板の酸化物系セラミックス基板との接合面側の銅の面積率が単位面積３０００μｍ×３０００μｍあたり６０％以下とすることができる。銅板を剥がした時に、この銅板の酸化物系セラミックス基板との接合面側の銅の面積率とは、剥がした銅板の酸化物系セラミックス基板との接合面側をＥＰＭＡによる面分析したとき、Ｃｕが最も多く検出される面積が単位面積３０００μｍ×３０００μｍ当り６０％以下になるということである。単位面積当りの銅の面積率が６０％以下ということは、残りの部分には酸化物系セラミックス基板から剥離した部分が付着した状態となっていることを示す。つまり、残りの部分では銅板と酸化物系セラミックス基板との接合が全面に渡って均一に行われていることを示す。より好ましい銅の面積率は４０％以下である。
　なお、ＥＰＭＡ面分析を行う際、一視野で単位面積３０００μｍ×３０００μｍの全体を測定できないときは、複数の視野に分割して測定してもよい。この場合は、例えば、３００μｍ×３００μｍの視野を連続して縦横に１０か所面分析して合計する方法が挙げられる。
　また、単位面積当りの銅の面積率が６０％以下を満たすことにより、銅板の接合強度が９．５ｋｇｆ／ｃｍ以上、さらには１０．５ｋｇｆ／ｃｍ以上となる。 Moreover, as a constituent material of the copper plate, tough pitch copper containing a predetermined amount of oxygen may be used, but a copper plate having a low oxygen content may be used. The thickness of the copper plate is preferably 0.2 to 0.5 mm. While the thickness of the oxide ceramic substrate is in the range of 0.3 to 1.2 mm, the difference in thermal expansion between the oxide ceramic substrate and the copper plate is achieved by setting the thickness of the copper plate to 0.2 to 0.5 mm. This improves the durability in the heat cycle test (TCT test).
The copper plate preferably contains 0.1 to 1.0% by mass of carbon. Since carbon functions as a deoxidizer, it is possible to obtain an effect of moving oxygen in the copper plate (tough pitch copper or oxygen-free copper) to the copper plate surface. The oxygen that has moved to the surface of the copper plate can be used to form a Cu—O eutectic when performing the direct bonding method. If the carbon content is less than 0.1% by mass, the effect of inclusion is not obtained. On the other hand, if the carbon content exceeds 1.0% by mass, the carbon content is excessively increased and the conductivity of the copper plate is lowered.
Further, when performing the direct bonding method, the surface roughness of the oxide ceramic substrate is preferably 0.1 to 0.7 μm in Ra. If the surface roughness Ra is less than 0.1 μm, highly accurate surface polishing is required, which increases costs. On the other hand, if the surface roughness Ra exceeds 0.7 μm, the surface is too rough and a gap is formed between the copper plate and the oxide-based ceramic substrate, and the eutectic reaction may not proceed sufficiently.
When an oxide ceramic circuit board is formed using such an oxide ceramic substrate, the area ratio of copper on the bonding surface side of the copper plate with the oxide ceramic substrate when the bonded copper plate is peeled off is a unit. The area may be 60% or less per 3000 μm × 3000 μm. When the copper plate is peeled off, the copper area ratio on the bonding surface side of the copper plate with the oxide-based ceramic substrate is determined by the surface analysis by EPMA on the bonding surface side of the peeled copper plate with the oxide-based ceramic substrate. This means that the most detected area is 60% or less per unit area of 3000 μm × 3000 μm. An area ratio of copper of 60% or less per unit area indicates that a portion peeled from the oxide ceramic substrate is attached to the remaining portion. That is, in the remaining part, it shows that joining of the copper plate and the oxide-based ceramic substrate is uniformly performed over the entire surface. A more preferable area ratio of copper is 40% or less.
In addition, when performing the EPMA surface analysis, if the entire unit area of 3000 μm × 3000 μm cannot be measured in one visual field, the measurement may be performed by dividing into a plurality of visual fields. In this case, for example, there is a method in which a field of view of 300 μm × 300 μm is continuously analyzed longitudinally and laterally at 10 points and totaled.
Further, when the copper area ratio per unit area satisfies 60% or less, the bonding strength of the copper plate becomes 9.5 kgf / cm or more, and further 10.5 kgf / cm or more.
　また、接合後の銅板の平均結晶粒径が３００～８００μｍであることが好ましい。直接接合法は、銅と酸素との共晶反応を利用する接合方法である。銅板中や銅板表面の酸素は銅板の結晶粒界に集まる。粒界に集まった酸素が共晶反応に使用されていくので、銅板の結晶粒界は適度なサイズを有することが好ましい。銅板の平均結晶粒径が３００μｍより小さいと粒界相が小さいまたは細くなり過ぎて接合強度の低下を招く。一方、平均結晶粒径が８００μｍを超えると、粒界相が大きくなり過ぎて単位面積当りの銅結晶粒界の割合が減るので接合強度の低下を招く。
　このように銅結晶粒サイズを調整した上で、銅結晶粒界に酸素を存在させることにより、接合強度を向上させ、さらにＴＣＴ特性を向上させることができる。なお、剥がした銅板の接合面側をＥＰＭＡにより酸素を面分析することにより銅結晶粒界に酸素が凝集していることが明白になる。 The average crystal grain size of the copper plate after bonding is preferably 300 to 800 μm. The direct bonding method is a bonding method using a eutectic reaction between copper and oxygen. The oxygen in the copper plate or on the surface of the copper plate collects at the crystal grain boundaries of the copper plate. Since oxygen collected at the grain boundaries is used for the eutectic reaction, it is preferable that the grain boundaries of the copper plate have an appropriate size. If the average crystal grain size of the copper plate is smaller than 300 μm, the grain boundary phase is too small or too thin, resulting in a decrease in bonding strength. On the other hand, if the average crystal grain size exceeds 800 μm, the grain boundary phase becomes too large and the ratio of the copper crystal grain boundary per unit area is reduced, leading to a reduction in bonding strength.
By adjusting the copper crystal grain size in this way and allowing oxygen to exist at the copper crystal grain boundary, the bonding strength can be improved and the TCT characteristics can be further improved. In addition, it is clear that oxygen is agglomerated at the copper crystal grain boundary by performing surface analysis of oxygen on the bonding surface side of the peeled copper plate by EPMA.
　このような構成を採用することにより、－４０℃×３０分→２５℃×１０分→１２５℃×３０分→２５℃×１０分を１サイクルとするＴＣＴ試験を１００サイクル実施した後においても、酸化物系セラミックス基板にクラックが発生しない酸化物系セラミックス回路基板とすることができる。
　また、－４０℃×３０分→２５℃×１０分→１２５℃×３０分→２５℃×１０分を１サイクルとするＴＣＴ試験を１００サイクル実施した後の銅板の接合強度を６．５ｋｇｆ／ｃｍ以上とすることもできる。
　本実施形態に係る酸化物系セラミックス回路基板によれば、銅板の銅結晶粒サイズや銅板の粒界相に酸素を凝集させることにより、酸化物系セラミックス基板と銅板との接合強度を向上させることができる。そのため、特にＴＣＴ特性が向上した酸化物系セラミックス回路基板を提供することができる。このような回路基板であれば、安価な酸化物系セラミックス基板の特性を生かしたコストメリットが高いセラミックス回路基板を提供することができる。 By adopting such a configuration, even after 100 cycles of the TCT test with -40 ° C. × 30 minutes → 25 ° C. × 10 minutes → 125 ° C. × 30 minutes → 25 ° C. × 10 minutes as one cycle, It can be set as the oxide type ceramic circuit board which a crack does not generate | occur | produce in an oxide type ceramic substrate.
Further, the bonding strength of the copper plate after performing 100 cycles of the TCT test in which one cycle is −40 ° C. × 30 minutes → 25 ° C. × 10 minutes → 125 ° C. × 30 minutes → 25 ° C. × 10 minutes is 6.5 kgf / cm It can also be set as above.
According to the oxide-based ceramic circuit board according to the present embodiment, the bonding strength between the oxide-based ceramic substrate and the copper plate is improved by aggregating oxygen in the copper crystal grain size of the copper plate or the grain boundary phase of the copper plate. Can do. Therefore, it is possible to provide an oxide-based ceramic circuit board with particularly improved TCT characteristics. With such a circuit board, it is possible to provide a ceramic circuit board with high cost merit utilizing the characteristics of an inexpensive oxide-based ceramic board.
（実施例１～５）
　酸化物系セラミックス基板として、アルミナ基板（縦５０ｍｍ×横３０ｍｍ×厚さ０．４ｍｍ、表面粗さＲａ０．３μｍ、密度３．７２ｇ／ｃｍ３）を用意した。金属回路板用銅板として、酸素含有量が５００質量ｐｐｍのタフピッチ銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍ、平均結晶粒径５０μｍ）を用意した。また、裏銅板用銅板として酸素含有量５００質量ｐｐｍのタフピッチ銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍを用意した。なお、銅板中の炭素含有量は０．１質量％未満のものを用いた。
　次に、インコネル６００製のトレイ上に、裏銅板／アルミナ基板／銅回路板の順に重ねて配置し積層体とした。
　図４に示すようなベルト炉６を使用して、表１に示す第一加熱領域、第二加熱領域、第三加熱領域を有する加熱工程を行って直接接合法を実施して実施例１～５に係る酸化物系セラミックス回路基板を調製した。なお、上記第一加熱領域、第二加熱領域、第三加熱領域における積層体の搬送距離は１０００ｍｍで統一した。また、ベルト炉６の入口カーテンおよび出口カーテンにおける窒素ガスの流量（Ａ），（Ｂ）は表１に示す値に設定した。
（比較例１）
　第二加熱工程および第三加熱工程を実施しない加熱工程にて直接接合法を実施した点以外は実施例１と同一方法で処理して比較例１に係る酸化物系セラミックス回路基板を調製した。 (Examples 1 to 5)
As an oxide ceramic substrate, an alumina substrate (length 50 mm × width 30 mm × thickness 0.4 mm, surface roughness Ra 0.3 μm, density 3.72 g / cm 3 ) was prepared. A tough pitch copper plate (length 40 mm × width 20 mm × thickness 0.5 mm, average crystal grain size 50 μm) having an oxygen content of 500 mass ppm was prepared as a copper plate for a metal circuit board. Moreover, a tough pitch copper plate (length 40 mm × width 20 mm × thickness 0.5 mm was prepared as the copper plate for the back copper plate with an oxygen content of 500 mass ppm. The carbon content in the copper plate was less than 0.1 mass%. Using.
Next, on the tray made from Inconel 600, the back copper plate / alumina substrate / copper circuit board were stacked in this order to form a laminate.
A belt furnace 6 as shown in FIG. 4 is used to carry out a direct bonding method by performing a heating process having a first heating region, a second heating region, and a third heating region shown in Table 1, and examples 1 to 5 was prepared. In addition, the conveyance distance of the laminated body in said 1st heating area | region, 2nd heating area | region, and 3rd heating area | region was unified at 1000 mm. Further, the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 1.
(Comparative Example 1)
An oxide-based ceramic circuit board according to Comparative Example 1 was prepared by performing the same process as in Example 1 except that the direct bonding method was performed in the heating process in which the second heating process and the third heating process were not performed.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（実施例６～９）
　酸化物系セラミックス基板として、アルミナ基板（縦５０ｍｍ×横３０ｍｍ×厚さ０．４ｍｍ、表面粗さＲａ０．５μｍ、密度３．６８ｇ／ｃｍ３）を用意した。また、金属回路板用銅板として、酸素含有量が５０質量ｐｐｍ以下の純銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍ、平均結晶粒径６０μｍ）を用意した。さらに、裏銅板用銅板として酸素含有量が５０質量ｐｐｍ以下の純銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍ）を用意した。なお、銅板中の炭素含有量は０．１質量％未満の銅材を用いた。
　次に、純銅板のアルミナ基板接合面側を加熱して膜厚４μｍの酸化銅膜を形成した。その後、インコネル６００製トレイ上に、裏銅板／アルミナ基板／銅回路板の順に重ね積層体として配置した。
　次に図４に示すようなベルト炉６を使用して、表２に示す第一加熱領域、第二加熱領域、第三加熱領域を有する加熱工程を実施して直接接合法を実施して実施例６～９に係る酸化物系セラミックス回路基板を調製した。なお、上記第一加熱領域、第二加熱領域、第三加熱領域における積層体の搬送距離は１０００ｍｍで統一した。また、ベルト炉６の入口カーテンおよび出口カーテンにおける窒素ガスの流量（Ａ），（Ｂ）は表２に示す値に設定した。
（実施例１０）
　酸化物系セラミックス基板として、アルミナ基板（縦５０ｍｍ×横３０ｍｍ×厚さ０．４ｍｍ、表面粗さＲａ０．５μｍ、密度３．６８ｇ／ｃｍ３）を用意した。また金属回路板用銅板として、酸素含有量が５０質量ｐｐｍ以下の純銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍ、平均結晶粒径６０μｍ）を用意した。さらに、裏銅板用銅板として酸素含有量が５０質量ｐｐｍ以下の純銅板（縦４０ｍｍ×横２０ｍｍ×厚さ０．５ｍｍ）を用意した。なお、銅板中の炭素含有量は０．１質量％未満の銅材を用いた。
　一方、銅回路板用銅板をプレス加工して、縦１５ｍｍ×横６ｍｍの回路要素を２つ形成し、それぞれブリッジ構造で繋いだ銅板を調製した。
　次に、インコネル６００製トレイ上に、裏銅板／アルミナ基板／銅回路板の順に重ねて積層体とし配置した。
　次に図４に示すようなベルト炉６を使用して、表２に示す第一加熱領域、第二加熱領域、第三加熱領域を有する加熱工程を実施して直接接合法を実施して実施例１０に係る酸化物系セラミックス回路基板を調製した。なお、上記第一加熱領域、第二加熱領域、第三加熱領域における積層体の搬送距離は１０００ｍｍで統一した。また、ベルト炉６の入口カーテンおよび出口カーテンにおける窒素ガスの流量（Ａ），（Ｂ）は表２に示す値に設定した。 (Examples 6 to 9)
As an oxide ceramic substrate, an alumina substrate (length 50 mm × width 30 mm × thickness 0.4 mm, surface roughness Ra 0.5 μm, density 3.68 g / cm 3 ) was prepared. In addition, a pure copper plate (40 mm long × 20 mm wide × 0.5 mm thickness, average crystal grain size 60 μm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for a metal circuit board. Furthermore, a pure copper plate (length 40 mm × width 20 mm × thickness 0.5 mm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for the back copper plate. In addition, the carbon content in a copper plate used the copper material less than 0.1 mass%.
Next, the alumina substrate bonding surface side of the pure copper plate was heated to form a 4 μm thick copper oxide film. Then, it arranged on the tray made from Inconel 600 as a laminated body in the order of back copper plate / alumina substrate / copper circuit board.
Next, using a belt furnace 6 as shown in FIG. 4, a heating process having a first heating region, a second heating region, and a third heating region shown in Table 2 is performed and a direct bonding method is performed. Oxide ceramic circuit boards according to Examples 6 to 9 were prepared. In addition, the conveyance distance of the laminated body in said 1st heating area | region, 2nd heating area | region, and 3rd heating area | region was unified at 1000 mm. Further, the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 2.
(Example 10)
As an oxide ceramic substrate, an alumina substrate (length 50 mm × width 30 mm × thickness 0.4 mm, surface roughness Ra 0.5 μm, density 3.68 g / cm 3 ) was prepared. Also, a pure copper plate (length 40 mm × width 20 mm × thickness 0.5 mm, average crystal grain size 60 μm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for a metal circuit board. Furthermore, a pure copper plate (length 40 mm × width 20 mm × thickness 0.5 mm) having an oxygen content of 50 mass ppm or less was prepared as a copper plate for the back copper plate. In addition, the carbon content in a copper plate used the copper material less than 0.1 mass%.
On the other hand, the copper plate for copper circuit boards was pressed to form two circuit elements each having a length of 15 mm and a width of 6 mm, and copper plates connected by a bridge structure were prepared.
Next, the back copper plate / alumina substrate / copper circuit board was stacked in this order on the Inconel 600 tray, and arranged as a laminate.
Next, using a belt furnace 6 as shown in FIG. 4, a heating process having a first heating region, a second heating region, and a third heating region shown in Table 2 is performed and a direct bonding method is performed. An oxide-based ceramic circuit board according to Example 10 was prepared. In addition, the conveyance distance of the laminated body in said 1st heating area | region, 2nd heating area | region, and 3rd heating area | region was unified at 1000 mm. Further, the flow rates (A) and (B) of nitrogen gas in the inlet curtain and outlet curtain of the belt furnace 6 were set to the values shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　次に、実施例１～９および比較例１に係る酸化物系セラミックス回路基板において、銅回路板をエッチングして縦１５ｍｍ×横６ｍｍの回路部を２個形成した。また、実施例１０に係る酸化物系セラミックス回路基板では、銅回路板のブリッジ部を削除した。
　回路部を形成した実施例１～１０および比較例１に係る酸化物系セラミックス回路基板に関して、銅回路板の接合強度を求めた。また、－４０℃×３０分→２５℃×１０分→１２５℃×３０分→２５℃×１０分を１サイクルとするＴＣＴ試験を１００サイクル行い、銅板の剥れの有無およびＴＣＴ試験後の銅板の接合強度を測定した。
　また、銅回路板を剥がした際の銅板の接合面側の銅の面積率を求めた。面積率の測定は、剥がした銅板の接合面側をＥＰＭＡ分析して銅が最も多く検出される面積率を単位面積３０００μｍ×３０００μｍ当りの割合で求めた。また、ＥＰＭＡの面分析によって酸素の凝集の有無を調査した。なお、ＥＰＭＡの分析は、単位面積３００μｍ×３００μｍを連続分析して合計３０００μｍ×３０００μｍになるまで求めた。また、接合後の銅板の平均結晶粒径も測定した。また、銅回路板にＮｉめっきを施し、濡れ性を調査した。
なお、上記濡れ性は、銅回路板に対するＮｉめっきの付着面積が１００％のものを○とし、９９％以下のものを△とした。
その測定調査結果を表３に示す。 Next, in the oxide ceramic circuit boards according to Examples 1 to 9 and Comparative Example 1, the copper circuit board was etched to form two circuit portions of 15 mm length × 6 mm width. In the oxide ceramic circuit board according to Example 10, the bridge portion of the copper circuit board was deleted.
For the oxide-based ceramic circuit boards according to Examples 1 to 10 and Comparative Example 1 in which the circuit part was formed, the bonding strength of the copper circuit board was determined. Also, 100 cycles of TCT test with -40 ° C. × 30 minutes → 25 ° C. × 10 minutes → 125 ° C. × 30 minutes → 25 ° C. × 10 minutes as one cycle. The bonding strength of was measured.
Moreover, the area ratio of the copper by the side of the joint surface of a copper plate when peeling a copper circuit board was calculated | required. The area ratio was measured by EPMA analysis of the bonded surface side of the peeled copper plate, and the area ratio at which the most copper was detected was determined at a rate per unit area of 3000 μm × 3000 μm. In addition, the presence or absence of oxygen aggregation was investigated by surface analysis of EPMA. In addition, the analysis of EPMA was obtained by continuously analyzing a unit area of 300 μm × 300 μm until a total area of 3000 μm × 3000 μm was obtained. Moreover, the average crystal grain size of the copper plate after joining was also measured. Moreover, Ni plating was given to the copper circuit board, and the wettability was investigated.
The wettability was evaluated as ◯ when the Ni plating adhesion area to the copper circuit board was 100%, and Δ when 99% or less.
The measurement survey results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　実施例１～８，１０に係る酸化物系セラミックス回路基板は、いずれも優れた特性を示した。なお、実施例９では窒素ガス流量の制御（Ａ／Ｂ）が１であったため、銅板表面のＮｉめっきとの濡れ性が低下した。銅回路板の表面にはデントライト組織が確認された。また、比較例１は第二加熱領域および第三加熱領域を設けていないために特性が低下した。
　また、本実施例に係る酸化物系セラミックス回路基板の製造方法であれば、その製造歩留りはいずれも８０～９０％の範囲であった。なお、不良原因の多くは、ベルト炉での搬送中での銅板の位置ずれによるものであった。この改善のために、銅板とアルミナ基板の間にアクリルバインダーを直径５ｍｍのドット状に塗布したところ、位置ずれの問題が解決し、製造歩留りが９７％以上と大幅に向上した。
（実施例１１～１４）
　実施例１の銅板を炭素含有量０．５質量％のタフピッチ銅板に代えた点以外は同一処理を繰り返して実施例１１に係る酸化物系セラミックス回路基板を調製した。
　また、実施例６の銅板を炭素含有量が０．２質量％の無酸素銅（純銅）に代えた点以外は同一処理を繰り返して実施例１２に係る酸化物系セラミックス回路基板を調製した。
　また、実施例１１のアルミナ基板を、アルミナとジルコニアとの混合焼結体（ジルコニア２０ｗｔ％、イットリア５ｗｔ％、アルミナ残部）に代えた点以外は同一処理を繰り返して実施例１３に係る酸化物系セラミックス回路基板を調製した。
　さらに、実施例１２のアルミナ基板を、アルミナとジルコニアとの混合焼結体（ジルコニア２０ｗｔ％、イットリア５ｗｔ％、アルミナ残部）に代えた点以外は同一処理を繰り返して実施例１４に係る酸化物系セラミックス回路基板を調製した。以下、実施例１１～１４の回路基板に対して、実施例１と同様の測定を行った。その結果を下記表４に示す。
Figure JPOXMLDOC01-appb-T000004
 　上記表４に示す結果から明らかなように、銅板に炭素を含有させることにより、接合強度の向上が確認できた。これは銅板中の炭素が脱酸剤として機能し、銅板中の酸素を銅板表面へと移動させ、移動した酸素がＣｕ－Ｏ共晶の形成に寄与したためと考えられる。 All of the oxide-based ceramic circuit boards according to Examples 1 to 8 and 10 exhibited excellent characteristics. In Example 9, since the nitrogen gas flow rate control (A / B) was 1, the wettability with the Ni plating on the copper plate surface was lowered. Dentrite structure was confirmed on the surface of the copper circuit board. Moreover, since the comparative example 1 did not provide the 2nd heating area | region and the 3rd heating area | region, the characteristic fell.
Further, in the manufacturing method of the oxide ceramic circuit board according to this example, the manufacturing yield was in the range of 80 to 90%. Many of the causes of defects were due to misalignment of the copper plate during conveyance in the belt furnace. For this improvement, when an acrylic binder was applied between the copper plate and the alumina substrate in the form of dots having a diameter of 5 mm, the problem of misalignment was solved, and the production yield was greatly improved to 97% or more.
(Examples 11 to 14)
An oxide-based ceramic circuit board according to Example 11 was prepared by repeating the same process except that the copper plate of Example 1 was replaced with a tough pitch copper plate having a carbon content of 0.5 mass%.
Further, the same treatment was repeated except that the copper plate of Example 6 was replaced with oxygen-free copper (pure copper) having a carbon content of 0.2% by mass to prepare an oxide-based ceramic circuit board according to Example 12.
In addition, the same treatment was repeated except that the alumina substrate of Example 11 was replaced with a mixed sintered body of alumina and zirconia (zirconia 20 wt%, yttria 5 wt%, remainder of alumina). A ceramic circuit board was prepared.
Further, the same treatment was repeated except that the alumina substrate of Example 12 was replaced with a mixed sintered body of alumina and zirconia (zirconia 20 wt%, yttria 5 wt%, remaining alumina), and the oxide system according to Example 14 was repeated. A ceramic circuit board was prepared. Thereafter, the same measurement as in Example 1 was performed on the circuit boards of Examples 11-14. The results are shown in Table 4 below.
Figure JPOXMLDOC01-appb-T000004
 As is clear from the results shown in Table 4 above, it was confirmed that the bonding strength was improved by adding carbon to the copper plate. This is presumably because carbon in the copper plate functions as a deoxidizer, oxygen in the copper plate moves to the copper plate surface, and the transferred oxygen contributes to the formation of the Cu—O eutectic.
　本発明に係る酸化物系セラミックス回路基板の製造方法によれば、所定の第一加熱領域、第二加熱領域、第三加熱領域でそれぞれ加熱工程を実施していることから共晶による接合反応を安定化させることができるので、セラミックス回路基板の製造歩留りを向上させることができる。また、本発明に係る酸化物系セラミックス回路基板は、接合強度が高く、ＴＣＴ特性を向上させることができる。 According to the method of manufacturing an oxide-based ceramic circuit board according to the present invention, since the heating process is performed in each of the predetermined first heating region, second heating region, and third heating region, the bonding reaction by eutectic is performed. Since it can be stabilized, the manufacturing yield of the ceramic circuit board can be improved. In addition, the oxide-based ceramic circuit board according to the present invention has high bonding strength and can improve TCT characteristics.
１…酸化物系セラミックス回路基板
１１…酸化物系セラミックス基板
１２…銅回路板（回路用銅板）
１３…銅板（裏銅板，裏金属板）
２…トレイ
３…搬送ベルト（ベルトコンベア）
４…搬入口（入口）
５…搬送口（出口）
６…ベルト炉（熱処理炉） DESCRIPTION OF SYMBOLS 1 ... Oxide type ceramic circuit board 11 ... Oxide type ceramic substrate 12 ... Copper circuit board (Copper board for circuits)
13 ... Copper plate (back copper plate, back metal plate)
2 ... Tray 3 ... Conveying belt (belt conveyor)
4 ... Carry-in entrance (entrance)
5 ... Conveying port (exit)
6 ... Belt furnace (heat treatment furnace)

Claims (21)

  1. 酸化物系セラミックス基板上に銅板を配置して積層体を形成する工程と、得られた積層体を加熱する工程とにより、酸化物系セラミックス基板と銅板とを一体に接合する酸化物系セラミックス回路基板の接合方法において、
    　上記加熱する工程は、１０６５～１０８５℃の間に加熱温度の極大値を有する第一加熱領域で積層体を加熱する工程と、次に１０００～１０５０℃の間に加熱温度の極小値を有する第二加熱領域で積層体を加熱する工程と、さらに１０６５～１１２０℃の間に加熱温度の極大値を有する第三加熱領域で積層体を加熱して接合体を形成する工程とを有し、その後接合体を冷却領域で冷却することを特徴とする酸化物系セラミックス回路基板の製造方法。     An oxide ceramic circuit for integrally bonding an oxide ceramic substrate and a copper plate by a step of forming a laminate by placing a copper plate on an oxide ceramic substrate and a step of heating the obtained laminate. In the substrate bonding method,
    The heating step includes a step of heating the laminate in a first heating region having a maximum heating temperature between 1065 and 1085 ° C., and a second step having a minimum heating temperature between 1000 and 1050 ° C. Heating the laminate in two heating regions, and further heating the laminate in a third heating region having a maximum heating temperature between 1065 and 1120 ° C. to form a joined body, and thereafter A method of manufacturing an oxide-based ceramic circuit board, wherein the joined body is cooled in a cooling region.
  2. 前記加熱工程は、銅板を配置した酸化物系セラミックス基板をトレイ上に載置し、搬送速度が７０～２７０ｍｍ／分のベルトコンベアでトレイを搬送しながら連続して各加熱工程を行うベルト炉を使用して実施することを特徴とする請求項１記載の酸化物系セラミックス回路基板の製造方法。 The heating step includes a belt furnace in which an oxide ceramic substrate on which a copper plate is disposed is placed on a tray, and each heating step is continuously performed while the tray is being conveyed by a belt conveyor having a conveyance speed of 70 to 270 mm / min. The method for producing an oxide-based ceramic circuit board according to claim 1, wherein the method is used.
  3. 前記トレイがニッケル合金から成ることを特徴とする請求項２記載の酸化物系セラミックス回路基板の製造方法。 3. The method of manufacturing an oxide-based ceramic circuit board according to claim 2, wherein the tray is made of a nickel alloy.
  4. 前記銅板はプレス加工により複数の回路要素とそれらの回路要素を繋ぐブリッジ部とを形成した回路構造を有し、前記銅板と酸化物系セラミックス基板とを接合後に、上記ブリッジ部を除去することを特徴とする請求項１ないし請求項３のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 The copper plate has a circuit structure in which a plurality of circuit elements and a bridge portion connecting the circuit elements are formed by press working, and the bridge portion is removed after the copper plate and the oxide-based ceramic substrate are joined. The method for producing an oxide-based ceramic circuit board according to any one of claims 1 to 3, wherein
  5. 前記酸化物系セラミックス基板と銅板とを接合後にエッチング工程により回路構造を形成することを特徴とする請求項１ないし請求項３のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 The method for manufacturing an oxide ceramic circuit board according to any one of claims 1 to 3, wherein the circuit structure is formed by an etching process after joining the oxide ceramic board and the copper plate.
  6. 前記加熱工程は、窒素ガス雰囲気中で実施することを特徴とする請求項１ないし請求項５のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 The method for manufacturing an oxide-based ceramic circuit board according to any one of claims 1 to 5, wherein the heating step is performed in a nitrogen gas atmosphere.
  7. 前記ベルト炉は、入り口カーテンの窒素流量（Ａ）と出口カーテンの窒素流量（Ｂ）の比Ａ／Ｂが０．２以下に制御された窒素ガス雰囲気を備えることを特徴とする請求項６記載の酸化物系セラミックス回路基板の製造方法。 The said belt furnace is equipped with the nitrogen gas atmosphere by which ratio A / B of the nitrogen flow rate (A) of an entrance curtain, and the nitrogen flow rate (B) of an exit curtain was controlled to 0.2 or less. Of manufacturing an oxide-based ceramic circuit board.
  8. 前記酸化物系セラミックス基板は、アルミナ焼結体、アルミナとジルコニアとの混合焼結体のいずれか１種から成ることを特徴とする請求項１ないし請求項７のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 8. The oxidation according to claim 1, wherein the oxide-based ceramic substrate is made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia. Manufacturing method of physical ceramic circuit board.
  9. 前記銅板の酸化物系セラミックス基板に配置される面に酸化膜を設ける工程を有することを特徴とする請求項１ないし請求項８のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 9. The method of manufacturing an oxide ceramic circuit board according to claim 1, further comprising a step of providing an oxide film on a surface of the copper plate disposed on the oxide ceramic substrate. .
  10. 前記銅板の接合強度が９．５ｋｇｆ／ｃｍ以上であることを特徴とする請求項１ないし請求項９のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 The method for producing an oxide-based ceramic circuit board according to any one of claims 1 to 9, wherein a bonding strength of the copper plate is 9.5 kgf / cm or more.
  11. 前記銅板中の炭素含有率が０．１～１．０質量％であることを特徴とする請求項１ないし請求項１０のいずれか１項に記載の酸化物系セラミックス回路基板の製造方法。 The method for producing an oxide-based ceramic circuit substrate according to any one of claims 1 to 10, wherein a carbon content in the copper plate is 0.1 to 1.0 mass%.
  12. 銅板と酸化物系セラミックス基板とを直接接合法により接合した酸化物系セラミックス回路基板において、銅板を剥がしたとき、銅板の酸化物系セラミックス基板との接合面側の銅の面積率が単位面積３０００μｍ×３０００μｍ当り６０％以下であり、銅板の接合強度が９．５ｋｇｆ／ｃｍ以上であることを特徴とする酸化物系セラミックス回路基板。 In an oxide-based ceramic circuit board in which a copper plate and an oxide-based ceramic substrate are bonded by a direct bonding method, when the copper plate is peeled off, the copper area ratio on the bonding surface side of the copper plate with the oxide-based ceramic substrate is 3000 μm. X An oxide-based ceramic circuit board characterized by having a copper plate bonding strength of 9.5 kgf / cm or more, which is 60% or less per 3000 μm.
  13. 前記酸化物系セラミックス基板が、アルミナ焼結体、アルミナとジルコニアとの混合焼結体のいずれか１種から成ることを特徴とする請求項１２記載の酸化物系セラミックス回路基板。 The oxide-based ceramic circuit board according to claim 12, wherein the oxide-based ceramic substrate is made of any one of an alumina sintered body and a mixed sintered body of alumina and zirconia.
  14. 前記酸化物系セラミックス回路基板を、温度－４０℃で３０分間保持し、次に温度２５℃で１０分間保持し、次に温度１２５℃で３０分間保持し、次に温度２５℃で１０分間保持する加熱工程を１サイクルとする熱サイクル試験（ＴＣＴ）を１００サイクル実施した後においても、酸化物系セラミックス基板にクラックが発生しないことを特徴とする請求項１２または請求項１３に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board is held at a temperature of −40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C. for 30 minutes, and then at a temperature of 25 ° C. for 10 minutes. 14. The oxide according to claim 12, wherein no crack is generated in the oxide-based ceramic substrate even after 100 cycles of a thermal cycle test (TCT) in which the heating step is one cycle. Ceramic circuit board.
  15. 前記酸化物系セラミックス基板の密度が３．６０～３．７９ｇ／ｃｍ３であることを特徴とする請求項１２ないし請求項１４のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit substrate according to any one of claims 12 to 14, wherein the oxide ceramic substrate has a density of 3.60 to 3.79 g / cm 3 .
  16. 前記酸化物系セラミックス回路基板を、温度－４０℃で３０分間保持し、次に温度２５℃で１０分間保持し、次に温度１２５℃で３０分間保持し、次に温度２５℃で１０分間保持する加熱工程を１サイクルとする熱サイクル試験（ＴＣＴ）を１００サイクル実施した後において、前記銅板の接合強度が６．５ｋｇｆ／ｃｍ以上であることを特徴とする請求項１２ないし請求項１５のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board is held at a temperature of −40 ° C. for 30 minutes, then at a temperature of 25 ° C. for 10 minutes, then at a temperature of 125 ° C. for 30 minutes, and then at a temperature of 25 ° C. for 10 minutes. The bonding strength of the copper plate is 6.5 kgf / cm or more after 100 cycles of a thermal cycle test (TCT) in which the heating step is 1 cycle. 2. The oxide-based ceramic circuit board according to claim 1.
  17. 前記銅板の厚さが０．２～０．５ｍｍであることを特徴とする請求項１２ないし請求項１６のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board according to any one of claims 12 to 16, wherein the copper plate has a thickness of 0.2 to 0.5 mm.
  18. 前記酸化物系セラミックス基板の表面粗さＲａが０．１～０．７μｍであることを特徴とする請求項１２ないし請求項１７のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board according to any one of claims 12 to 17, wherein a surface roughness Ra of the oxide ceramic substrate is 0.1 to 0.7 µm.
  19. 前記銅板の結晶粒界に酸素が存在することを特徴とする請求項１２ないし請求項１８のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board according to any one of claims 12 to 18, wherein oxygen is present in a crystal grain boundary of the copper plate.
  20. 前記銅板の平均結晶粒径が３００～８００μｍであることを特徴とする請求項１２ないし請求項１９のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board according to any one of claims 12 to 19, wherein an average crystal grain size of the copper plate is 300 to 800 µm.
  21. 前記銅板の炭素含有率が０．１～１．０質量％であることを特徴とする請求項１２ないし請求項２０のいずれか１項に記載の酸化物系セラミックス回路基板。 The oxide ceramic circuit board according to any one of claims 12 to 20, wherein the copper plate has a carbon content of 0.1 to 1.0 mass%.
PCT/JP2012/068957 2011-07-28 2012-07-26 Method of manufacturing oxide ceramic circuit board, and oxide ceramic circuit board WO2013015355A1 (en)

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