Apparatus and method for producing (metal plate)-(ceramic board) laminated assembly, and apparatus and method for producing power-module substrate
09725367 · 2017-08-08
Assignee
Inventors
Cpc classification
C04B2237/126
CHEMISTRY; METALLURGY
H01L2924/0002
ELECTRICITY
C04B2237/706
CHEMISTRY; METALLURGY
H01L21/67144
ELECTRICITY
C04B2237/128
CHEMISTRY; METALLURGY
C04B2237/704
CHEMISTRY; METALLURGY
H05K3/022
ELECTRICITY
H01L2924/0002
ELECTRICITY
B23K1/19
PERFORMING OPERATIONS; TRANSPORTING
H01L2924/00
ELECTRICITY
C04B2237/127
CHEMISTRY; METALLURGY
C04B2237/86
CHEMISTRY; METALLURGY
B23K1/0016
PERFORMING OPERATIONS; TRANSPORTING
H01L2924/00
ELECTRICITY
H01L23/3735
ELECTRICITY
H05K2203/068
ELECTRICITY
International classification
B23K31/02
PERFORMING OPERATIONS; TRANSPORTING
H01L21/48
ELECTRICITY
B23K1/00
PERFORMING OPERATIONS; TRANSPORTING
B23K1/19
PERFORMING OPERATIONS; TRANSPORTING
H05K3/02
ELECTRICITY
H01L23/373
ELECTRICITY
H01L21/67
ELECTRICITY
H05K3/00
ELECTRICITY
Abstract
Provided are: an apparatus and a method for producing a (metal plate)-(ceramic board) laminated assembly, a bonding material and a metal plate during the bonding of the metal plate to the ceramic board through the bonding-material layer and an apparatus and a method for producing a power-module substrate. An apparatus for producing a (metal plate)-(ceramic board) laminated assembly by laminating a metal plate having a temporary bonding material formed thereon on a ceramic board having a bonding-material layer formed thereon, the apparatus being equipped with: a conveying device which conveys the metal plate onto the ceramic board to laminate the ceramic board and the metal plate on each other; and a heating device which is arranged in the middle of a passage of the conveyance of the metal plate by the conveying device and melts the temporary-bonding material on the metal plate.
Claims
1. A method for producing (metal plate)-(ceramic board) laminated assembly wherein a bonding-material layer is formed on one of a ceramic board or a metal plate, temporary-bonding material is formed on one plate of the ceramic board or the metal plate, the ceramic board and the metal plate are temporarily stuck together in a piled state with the bonding-material layer therebetween by the temporary-bonding material, so that the ceramic board and the metal plate are laminated, the method comprising a forming step of the solidified temporary-bonding material on one plate of the ceramic board or the metal plate, and a laminating step comprising the steps of conveying the one plate onto the other plate of the ceramic board or the metal plate, melting the temporary-bonding material on the way of conveying, laminating the ceramic board and the metal plate, in a state in which the temporary-bonding material is melted, and then solidified the temporary-bonding material.
2. The method for producing (metal plate)-(ceramic board) laminated assembly according to claim 1, wherein in the laminating step, temperature of the temporary-bonding material or the one plate is measured while conveying.
3. The method for producing (metal plate)-(ceramic board) laminated assembly according to claim 1, wherein after laminating the metal plate and the ceramic board, the temporary-bonding material is cooled.
4. The method for producing (metal plate)-(ceramic board) laminated assembly according to claim 2, wherein after laminating the metal plate and the ceramic board, the temporary-bonding material is cooled.
5. A method for producing power-module substrate, wherein the ceramic board and the metal plate are bonded by pressurizing in a laminating direction and heating a (metal plate)-(ceramic board) laminated assembly obtained by the method for producing (metal plate)-(ceramic board) laminated assembly according to claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF EMBODIMENTS
(15) Below, embodiments of the present invention will be explained referring drawings.
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(17) This power-module substrate 10 is provided with: a ceramic substrate 20; a copper-circuit plate (i.e., a metal plate of the present invention) 30 bonded on one surface of the ceramic substrate 20; and a heat-radiation plate 40 bonded on an opposite surface of the ceramic substrate 20. In this case, the ceramic substrate 20 and the heat-radiation plate 40 are formed to have a square-flat board shape; on the other hand, the copper-circuit plate 30 is formed to have a desired circuit pattern.
(18) In the power-module substrate 10, a heat sink 50 is bonded on a surface of the heat-radiation plate 40 at an opposite side to the ceramic substrate 20; an electronic component 60 such as a semiconductor chip or the like is bonded by a soldering layer 61 on the copper-circuit plate 30; and the electronic component 60 and the copper-circuit plate 30 are connected by a bonding wire or the like (not illustrated), so that a power module is configured.
(19) Mold resin (not illustrated) seals the whole as necessary. The soldering layer 61 is made of solder, such as Sn—Cu based solder, Sn—Ag—Cu based solder, Zn—Al based solder or Pb—Sn based solder.
(20) The ceramic substrate 20 is made of, for example, nitride ceramic such as AlN (aluminum nitride), Si.sub.3N.sub.4 (silicon nitride) or the like, oxide ceramic such as Al.sub.2O.sub.3 (alumina) or the like as a base material, and formed to have a square shape. A thickness of the ceramic substrate 20 is set to 0.125 mm to 1.0 mm.
(21) The copper-circuit plate 30 is made of pure copper such as oxygen-free copper, tough-pitch copper or the like or copper alloy (in this invention, simply called copper) and formed to have a desired circuit pattern by punching out a plate material by a press. A thickness of the copper-circuit plate 30 is set to 0.3 mm to 4 mm. As described below, the copper-circuit plate 30 is bonded on the ceramic substrate 20 by bonding material made from active-metal brazing material such as Ag—Ti, Ag—Ti—Cu or the like including active metal such as Ti or the like.
(22) The heat-radiation plate 40 is made of pure aluminum with purity of 99.90% or higher or aluminum alloy (simply called aluminum), having a thickness of 0.2 mm to 2 mm, and ordinary formed to have a smaller square-flat board shape than the ceramic substrate 20. The heat-radiation plate 40 is bonded to the ceramic substrate 20 by bonding material of brazing material such as Al—Si based, Al—Ge based, Al—Cu based, Al—Mg based or Al—Mn based or the like.
(23) Next, an apparatus for producing the (metal plate)-(ceramic board) laminated assembly 11 (refer to
(24) A producing apparatus 100 of (metal plate)-(ceramic board) laminated assembly shown in
(25) The ceramic board 21 is formed to have size in which the ceramic substrates 20 configuring the power-module substrate 10 can be produced in an arranged state. Pieces of the substrates 10 for power modules can be produced by: bonding the (metal plate)-(ceramic board) laminated assembly 11 with pressurizing and heating; then bonding the heat-radiation plate 40 on an opposite surface of the ceramic board 21; and then dividing the ceramic board 21. The copper-circuit plate 30 and the heat-radiation plate 40 having a product shape used for each of the substrates 10 for power modules are used.
(26) As shown in
(27) Furthermore, the producing apparatus 100 is provided with a supplying device 5 arranging the copper-circuit plate 30 on the mounting table 1. The supplying device 5 is provided with: a supplying stage 52 moving a tray 51 in which copper-circuit plates 30 are held to a prescribed position in a state in which applied surfaces 31 of the temporary-bonding material 72 are upward; a receiving-pickup cylinder 53 picking pieces of the copper-circuit plates 30 up from the tray 51 on the supplying stage 52; and an inverting device 54 supplying the copper-circuit plates 30 received from the receiving-pickup cylinder 53, in a state in which the applied surfaces 31 of the temporary-bonding material are downward by inverting, onto the mounting table 1.
(28) For example, the supplying stage 52 is configured to movable between a position in which an operator can mount the tray 51 (a position denoted by the two-dotted chain line) and a position in which the copper-circuit plate 30 can be picked up by the receiving-pickup cylinder 53, so as to convey the tray 51 mounted on the supplying stage 52 by the operator to an operational position of the receiving-pickup cylinder 53. Moreover, on the supplying stage 52, an alignment device 55 holding the supplying stage 52 at the position in which the copper-circuit plate 30 can be picked up by the receiving-pickup cylinder 53 is provided.
(29) The receiving-pickup cylinder 53 picks up the copper-circuit plates 30 one by one from the tray 51, and moves them to a turning stage 56 of the inverting device 54, and is held movably along xyz-axes direction by a driving mechanism 6 mentioned below, used for the conveying device 3.
(30) The inverting device 54 is configured from the turning stage 56 held by a rotary actuator 57 so as to be possible to pivot on a spindle 58 by 180° as shown in
(31) On the mounting table 1, guide walls 1a and 1b which are orthogonally arranged to each other, and pusher portions 15a and 15b which are held movably back and forth toward the guide walls 1a and 1b are provided in order to align the copper-circuit plate 30. As shown in the part (a) of
(32) The conveying device 3 is configured form a laminating-pickup cylinder 33 provided moveably along xyz-axes direction by the driving mechanism 6. The driving mechanism 6 is provided with the movable receiving-pickup cylinder 53 other than the laminating-pickup cylinder 33.
(33) This conveying device 3 conveys the copper-circuit plate 30 mounted on the mounting table 1 in a state in which the applied surface 31 is downward to the base table 2 on which the ceramic board 21 is mounted in a state in which the applied surface 31 is downward, and laminates the applied surface 31 of the copper-circuit plate 30 on the ceramic board 21 on the base table 2; so that the copper-circuit plate 30 and the ceramic board 21 are laminated. Specifically, as shown in
(34) The base table 2 is installed on a supplying stage 22 which is movable between a position in which the operator can mount the ceramic board 21 (a position shown by the two-dotted chain line in
(35) On the conveying path of the copper-circuit plate 30 by the conveying device 3, the heating device 4 melting the temporary-bonding material 72 of the copper-circuit plate 30 is provided.
(36) As shown in
(37) The conveying device 3 is provided with a temperature-measuring device 34 which can observe a melted state of the temporary-bonding material 72 while conveying the copper-circuit plate 30. Accordingly, it is possible to confirm melted states of the temporary-bonding material 72 at the time: when the copper-circuit plate 30 is heated by the heating device 4, when the copper-circuit plate 30 is laminated on the ceramic board 21, and after the copper-circuit plate 30 and the ceramic board 21 are laminated each other. In addition, as the temperature-measuring device 34, for example, an infrared thermometer or the like may be used, and it is configured to measure temperature of the copper-circuit plate 30 held by the laminating-pickup cylinder 33 in this embodiment.
(38) Moreover, the producing apparatus 100 is provided with a cooling device 35 cooling the copper-circuit plate 30 and the ceramic board 21 after laminating. The cooling device 35 is configured from a cooling nozzle which blows air, as shown in the part (b) of
(39) Next, a method for producing the (metal plate)-(ceramic board) laminated assembly 11 using the above-mentioned producing apparatus 100 will be explained.
(40) On one surface of the ceramic board 21, as shown in
(41) On one surface of the copper-circuit plate 30, as shown in
(42) The copper-circuit plates 30 on which the temporary-bonding material 72 is applied are disposed in the recessed portions in the tray 51 in a state in which the temporary-bonding material 72 upward, and conveyed onto the supplying stage 52. In addition, the temporary-bonding material 72 may be applied on the copper-circuit plate 30 by dropping the temporary-bonding material 72 on the copper-circuit plate 30 disposed in the tray 51.
(43) First, the tray 51 is disposed on the supplying stage 52, and then moved to a pick-up position for the copper-circuit plate 30 by the receiving-pickup cylinder 53. Then, each of pieces of the copper-circuit plates 30 in the tray 51 is picked up one by one by the receiving-pickup cylinder 53, moved to the turning stage 56, and arranged on the mounting table 1 in a state in which the applied surface 31 of the temporary-bonding material 72 is inverted downward from upward.
(44) Next, the copper-circuit plate 30 on the mounting table 1 is conveyed by the laminating-pickup cylinder 33 in a state in which the applied surface 31 is downward. While conveying the copper-circuit plate 30 from the mounting table 1 to the base table 2, the applied surface 31 of the copper-circuit plate 30 is faced to the rubber heater 41 so as to be heated. The temporary-bonding material 72 is melted by being heated by the rubber heater 41. At this time, the melting state of the temporary-bonding material 72 can be observed by the temperature-measuring device 34.
(45) In the state in which the temporary-bonding material 72 is melted, as shown in the part (a) of
(46) As described above, even though the temporary-bonding material 72 applied on the copper-circuit plate 30 is solidified when conveying, the temporary-bonding material 72 can be melted by heating by the heating device 4 while conveying the copper-circuit plate 30 from the mounting table 1 to the base plate 2. Then, the copper-circuit plate 30 can be laminated on the ceramic board 21 in a state in which the temporary-bonding material 72 is melted.
(47) In the (metal plate)-(ceramic board) laminated assembly 11 produced as above, the copper-circuit plate 20 is temporarily tacked on the bonding-material layer 71 on the ceramic board 21 by the temporary-bonding material 72, so that the copper-circuit plate 30 and the bonding-material layer 71 on the ceramic board 21 is prevented from being misaligned while bonding operations or the like in the subsequent bonding process; accordingly, the copper-circuit plate 30 can be bonded on the prescribed position of the ceramic board 21 with an accurately positioned state.
(48) In addition, in the (metal plate)-(ceramic board) laminated assembly 11, the ceramic board 21 and the copper-circuit plate 30 can be bonded by the bonding-material layer 71 therebetween by heating in vacuum remaining the pressurizing state in the laminating direction. Since the bonding material includes active metal, being heated in vacuum, Ti which is active metal reacts to N or O included in the ceramic board 21 and forms nitride, oxide and the like on the surface of the ceramic plate 21; and Ag forms a melted-metal layer by reacting to Cu of the copper-circuit plate 30: and by cooling and solidifying it, the copper-circuit plate 30 and the ceramic board 21 are bonded with an Ag—Cu eutectic layer therebetween. The temporary-bonding material 72 is decomposed and disappeared in an initial stage of this heating.
(49) The heat-radiation plate 40 is bonded to the ceramic board 21 by bonding material such as Al—Si based brazing material, Al—Ge based brazing material, Al—Cu based brazing material, Al—Mg based brazing material, Al—Mn based brazing material or the like. As a bonding method, such methods can be adopted like: laminating the heat-radiation plate 40 and the ceramic board 21 with the bonding material (a brazing-material foil) therebetween; or temporarily tacking the bonding material on an aluminum plate for forming the heat-radiation plate 40 by welding or the like, and then punching out it so as to make the heat-radiation plate 40 on which the bonding material is temporarily tacked, and laminating the bonding material side of the heat-radiation plate 40 on the ceramic board 21. In the laminating operation of the heat-radiation plate 40, the producing apparatus 100 of the (metal plate)-(ceramic board) laminated assembly of the present embodiment can also be used.
(50) The heat-radiation plates 40 each are laminated one by one corresponding to a bonding position of each of the copper-circuit plates 30 on the ceramic board 21 at an opposite surface to the bonding surface for the copper-circuit plate 30. Similar to the above-mentioned bonding process of the copper-circuit plate 30, the bonding material (brazing material) and a part of aluminum in the heat-radiation plate 40 are melted by laminating the laminated assemblies laminating heat-radiation plate 40 and heating them in a vacuum heating furnace in a state of being pressurized in the laminating direction: and then the heat-radiation plate 40 is bonded on the ceramic board 21 by cooling and solidifying.
(51) Making grooves on the ceramic board 21 between the copper-circuit plates 30 by a laser processing or the like, and dividing the ceramic board 21 along the grooves, the respective power-module substrates 10 in which the copper-circuit plate 30 is bonded on one surface of the ceramic board 20 and the heat-radiation plate 40 is bonded on the opposite surface of the ceramic board 20 are made as shown in
(52) As described above, in the producing apparatus 100 of (metal plate)-(ceramic board) laminated assembly of this embodiment, the heating device 4 is provided in the conveying path of the copper-circuit plate 30. Therefore, it is possible to laminate the copper-circuit plate 30 and the ceramic board 21 immediately in the state in which the temporary-bonding material 72 is melted, so that the copper-circuit plate 30 and the ceramic board 21 can be reliably bonded together with the bonding-material layer 71 therebetween.
(53) The (metal plate)-(ceramic board) laminated assembly 11 is subsequently heated so that the ceramic board 21 and the copper-circuit plate 30 are bonded by the bonding material. In this bonding process, a pressurizing tool 110 shown in
(54) The (metal plate)-(ceramic board) laminated assemblies 11 are arranged in a heating furnace 120 together with the pressurizing tool 110 in a state in which the pressurizing tool 110 presses the (metal plate)-(ceramic board) laminated assemblies 11, and heated in vacuum at temperature of 800° C. or higher and 930° C. or lower for 1 minute to 60 minutes; so that the ceramic board 21 and the copper-circuit plate 30 are brazed. The bonding device of the present invention is configured from the pressurizing tool 110 and the heating furnace 120 in this embodiment.
(55) In this bonding process likewise, the ceramic board 21 and the bonding-material layer 71 do not shift from the copper-circuit plate 30; and these are held in the positioned state. Accordingly, the bonding material is prevented from flowing out of the copper-circuit plate 30; and it is possible to produce the power-module substrates 10 efficiently.
(56) Moreover, the temporary-bonding material 72 including polyethylene glycol as major ingredient is immediately decomposed before rising up to bonding temperature in the bonding process, so that bonded surfaces are not influenced.
(57) In the producing apparatus 100 of (metal plate)-(ceramic board) laminated assembly of the present embodiment, the copper-circuit plate 30 can be conveyed by the supplying device 5 in the state in which the applied surface 31 of the temporary-bonding material 72 is downward; so that the copper-circuit plate 30 can be arranged on the ceramic board 21 immediately after melting the temporary-bonding material 72.
(58) Since the cooling device 35 is provided so as to actively cool the copper-circuit plate 30 and the ceramic board 21 after laminating, it can be immediately made into the state of positioning the copper-circuit plate 30 on the ceramic board 21. Accordingly, it is possible to improve efficiency of the producing process of the power-module substrate 10.
(59) By the temperature-measuring device 34, the melting state of the temporary-bonding material 72 can be confirmed. Therefore, it is possible to precisely bond the ceramic board 21 and the copper-circuit plate 30 with the bonding-material layer 71 therebetween without poor-quality of temporal-tacking.
(60) Moreover, by providing the temperature-measuring device 34 at the conveying device 3 conveying the copper-circuit plate 30, it is possible to confirm the melting state of the temporary-bonding material 72 by the one temperature-measuring device 34 at timings of: heating the copper-circuit plate 30; laminating the copper-circuit plate 30 on the ceramic board 21; and after laminating the copper-circuit plate 30 and the ceramic board 21. Therefore, it is possible to laminate the ceramic board 21 in a state in which the temporary-bonding material 72 is melted altogether; and the (metal plate)-(ceramic board) laminated assembly 11 can be treated in the temporal-tacking state of the copper-circuit plate 30 and the ceramic board 21 after laminating. Accordingly, it is reliably possible to prevent the misalignment of the ceramic board 21 and the copper-circuit plate 30.
(61) In the above-mentioned embodiment, the temporary-bonding material is applied on the copper-circuit plate, and the copper-circuit plate is conveyed and laminated on the ceramic board. Conversely, the ceramic board may be conveyed and laminated on the copper-circuit plate after applying the temporary-bonding material on the bonding-material layer of the ceramic board.
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(63) As shown in the part (a) of
(64) In this embodiment, the ceramic board 25 is the one plate of the present invention; and the copper-circuit plate 30 is the other plate of the present invention.
(65) The present invention is not limited to the above-described embodiments and various modifications may be made without departing from the scope of the present invention.
(66) For example, the embodiments of cases of producing a power-module substrate in which a copper-circuit plate and a ceramic board are bonded are explained. The present invention may be used for a power-module substrate using a metal plate other than a copper-circuit plate (e.g., aluminum, aluminum alloy or the like), for bonding the metal plate and a ceramic board.
(67) The present invention is not limited to a power-module substrate: but the present invention can further be used for cases of producing a bonded assembly of a ceramic board and a metal plate for other use than a power module. In those cases, it is applicable to bond these laminated assemblies ((metal plate)-(ceramic board) laminated assemblies) in bonding conditions other than a condition including both pressurizing and heating.
(68) In the above embodiments, although the temporary-bonding material including polyethylene glycol as major ingredient is used, the temporary-bonding material is not limited to this. For example, liquid paraffin, wax and the like can be used.
(69) Although the bonding-material layer configured from active-metal brazing material is formed on the ceramic board in the embodiments, the bonding-material layer may be formed on the copper-circuit plate. Moreover, the temporary-bonding material may be formed on the bonding-material layer instead of a surface of the ceramic board or the copper-circuit plate.
(70) The bonding-material layer 71 of the above-described embodiment may be formed by using a foil of active-metal brazing material.
INDUSTRIAL APPLICABILITY
(71) The present invention enables to prevent a misalignment of the ceramic board, the bonding-material layer, and the metal plate when bonding the metal plate and the ceramic board with the bonding-material layer therebetween, and is applicable suitably for producing a power-module substrate.
DESCRIPTION OF REFERENCE SYMBOLS
(72) 1 mounting table 2 base table 3 conveying device 4 heating device 5 supplying device 6 driving mechanism 10 power-module substrate 11 (metal plate)-(ceramic board) laminated assembly 15a, 15b pusher portion 20 ceramic substrate 21 ceramic board (the other plate) 22 supplying stage 23 guide pin 25 ceramic board (one plate) 30 copper-circuit plate (metal plate; the one plate) 31 applied surface 33 laminating-pickup cylinder 34 temperature-measuring device 35 cooling device 40 heat-radiation plate 41 rubber heater 50 heat sink 51 tray 52 supplying stage 53 receiving-pickup cylinder 54 inverting device 55 alignment device 56 turning stage 56a recessed portion 57 rotary actuator 58 spindle 60 electronic component 61 soldering layer 71 bonding-material layer 72 temporary-bonding material 110 pressurizing tool (bonding device) 120 heating furnace (bonding device)