JP2013030523A - Method of manufacturing metal-ceramic junction circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a metal-ceramic junction circuit board with ease and at low cost in which a metal circuit board is joined onto one face of a ceramic substrate and a metal base plate for heat release is joined onto the other face.SOLUTION: A metal-ceramic junction substrate 10' is manufactured in which a metal plate 14' for a circuit is joined onto one face of a ceramic substrate 12 and a metal base plate 16 is joined onto the other face. A resist 26 is formed so as to cover the surface of the metal plate for a circuit and metal base plate of the metal-ceramic junction substrate. Unwanted parts of the resist are removed by radiating laser light onto the resist. Thereafter, parts where the surface of the metal plate for a circuit and metal base plate are exposed are subjected to etching. Thus, a metal-ceramic junction circuit board 10 is manufactured in which a metal circuit board 14 is joined onto one face of a ceramic substrate and a metal base plate is joined onto the other face.

Description

  The present invention relates to a method of manufacturing a metal / ceramic bonding circuit board, and in particular, a metal plate (metal circuit board) for mounting electronic components is formed on one surface of a ceramic substrate, and a metal base plate for heat dissipation is formed on the other surface. The present invention relates to a method for manufacturing a metal / ceramic bonding circuit board on which is formed.

  In conventional power modules used to control large currents in electric vehicles, trains, machine tools, etc., a metal-ceramic insulating substrate is soldered to one side of a metal plate or composite material called a base plate. The semiconductor chip is fixed on the metal-ceramic insulating substrate by soldering. Further, a metal radiating fin or a cooling jacket is attached to the other surface (back surface) of the base plate through heat conductive grease by screwing or the like.

  Since the base plate and the semiconductor chip are soldered to the metal-ceramic insulating substrate by heating, the base plate is likely to warp due to the difference in thermal expansion coefficient between the joining members during soldering. Also, the heat generated from the semiconductor chip is released to the air and cooling water by the heat radiation fins and the cooling jacket through the metal-ceramic insulating substrate, the solder, and the base plate, so that the base plate warps during soldering. , The clearance when radiating fins and cooling jackets are attached to the base plate is increased, and the heat dissipation is extremely reduced. Furthermore, since the thermal conductivity of the solder itself is low, a higher heat dissipation is required for a power module through which a large current flows.

  In order to solve these problems, a metal base plate made of aluminum or aluminum alloy is directly bonded to one surface of the ceramic substrate, and a metal plate for circuit made of aluminum or aluminum alloy is directly bonded to the other surface. A ceramic bonded substrate has been proposed (see, for example, Patent Document 1). In this metal-ceramic bonding substrate, a ceramic substrate is arranged inside a mold, a molten aluminum or aluminum alloy is poured into the mold, brought into contact with both surfaces of the ceramic substrate, and then cooled and solidified (so-called so-called). It can be manufactured by molten metal bonding).

  In order to manufacture a metal-ceramic circuit board using such a metal-ceramic bonding board, the surface of the circuit metal plate and the metal base board bonded to the ceramic substrate is polished and machined, and then the circuit metal board A UV-curable resist ink is screen printed in a circuit pattern shape and UV cured to form a circuit pattern resist, and a thermosetting resist is applied to the entire surface of the metal base plate with a dispenser and thermally cured. After a resist is formed on the entire surface of the metal base plate, a chemical-resistant tape is applied to the end of the metal base plate, the metal-ceramic bonding substrate (workpiece) is fixed to an etching jig, and then etched. After removing the workpiece from the etching jig, remove the resist and remove the tape. That.

  On the other hand, a method for manufacturing a printed wiring board by coating a resist on a metal foil to be a conductor, forming a pattern by etching after removing a predetermined portion of the resist by laser irradiation (for example, a patent) Reference 2).

Japanese Patent Laying-Open No. 2005-74434 (paragraph numbers 0013 to 0015) JP-A-10-270826 (paragraph numbers 0007 to 0008)

  However, when manufacturing a metal / ceramic bonding circuit board in which a metal circuit board is bonded to one surface of a ceramic substrate and a metal base plate for heat dissipation is bonded to the other surface, unlike a flat printed wiring board. Before etching, it is necessary not only to form a circuit pattern resist on the circuit metal plate, but also to form a resist on the surface of the metal base plate, and at the end of the metal base plate on which the resist is formed. Since it is necessary to apply the tape manually, labor and time are required, and the cost increases.

  Therefore, in view of such a conventional problem, the present invention provides a metal-ceramic bonding circuit board in which a metal circuit board is bonded to one surface of a ceramic substrate and a metal base plate for heat dissipation is bonded to the other surface. It is an object of the present invention to provide a method for producing a metal / ceramic bonding circuit board which can be easily and inexpensively produced.

  As a result of diligent research to solve the above problems, the inventors of the present invention manufactured a metal-ceramic bonding substrate in which a circuit metal plate was bonded to one surface of a ceramic substrate and a metal base plate was bonded to the other surface. Then, a resist is formed so as to cover the surfaces of the metal plate for circuit and metal base plate of the metal-ceramic bonding substrate, and the resist is irradiated with laser light to remove unnecessary portions of the resist, and then the circuit metal Metal-ceramic bonding in which a metal circuit board is bonded to one surface of a ceramic substrate and a metal base plate for heat dissipation is bonded to the other surface by etching the exposed portions of the surface of the plate and the metal base plate The present inventors have found that a circuit board can be easily and inexpensively manufactured and have completed the present invention.

  That is, the method for producing a metal / ceramic bonding circuit board according to the present invention produces a metal / ceramic bonding board in which a circuit metal plate is bonded to one surface of a ceramic substrate and a metal base plate is bonded to the other surface, A resist is formed so as to cover the surfaces of the circuit metal plate and the metal base plate of the metal-ceramic bonding substrate, and unnecessary portions of the resist are removed by irradiating the resist with laser light, and then the circuit metal plate and Etching the exposed surface of the metal base plate to manufacture a metal-ceramic bonding circuit board in which the metal circuit board is bonded to one surface of the ceramic substrate and the metal base plate is bonded to the other surface It is characterized by.

  In this metal-ceramic bonding circuit board manufacturing method, a metal-ceramic bonding board is a metal-ceramic bonding board in which a circuit metal plate is directly bonded to one surface of a ceramic substrate and a metal base plate is directly bonded to the other surface. The metal-ceramic bonding circuit board is preferably a metal-ceramic bonding circuit board in which the metal circuit board is directly bonded to one surface of the ceramic substrate and the metal base plate is directly bonded to the other surface. In addition, the metal-ceramic bonding substrate is manufactured by disposing a ceramic substrate inside the mold, pouring a molten metal into the mold, bringing it into contact with both surfaces of the ceramic substrate, and then cooling and solidifying it. Is preferred.

  Further, in the above method for manufacturing a metal / ceramic bonding circuit board, the resist portion formed so as to cover the upper surfaces of the circuit metal plate and the metal base plate is a planar region that covers the upper surface of the circuit metal plate. 1 area, a second area that is a plane area including a step covering the upper surface of the metal base plate, and a third area that is an area including an inclined surface between the first area and the second area. In addition, it is preferable to irradiate the laser light by adjusting the depth of focus in the height direction of the laser light for each region. Moreover, it is preferable that laser beam irradiation is performed by a carbon dioxide laser irradiation apparatus or a Yb laser irradiation apparatus.

  In the method for producing a metal / ceramic bonding circuit board, the surfaces of the circuit metal plate and the metal base plate are preferably polished before the resist is formed. Also, before forming the resist, it is preferable to chamfer the edge portion of the ceramic substrate of the metal base plate in an R shape, and this chamfering is preferably performed so as to be R0.15 to 5.0 mm.

  Furthermore, in the above-described method for producing a metal / ceramic bonding circuit board, the resist is preferably formed by applying a resist ink to the entire surface of the circuit metal plate and the metal base plate by spray coating and curing the resist ink. In this case, it is preferable to heat the metal / ceramic bonding substrate in advance before forming the resist. Further, it is preferable that the resist ink is an ultraviolet curable resist ink containing acryl polymer or a resist removal type resist ink.

  In the method for producing a metal / ceramic bonding circuit board, the circuit metal plate and the metal base plate are preferably made of aluminum or an aluminum alloy.

  According to the present invention, it is possible to easily and inexpensively manufacture a metal-ceramic bonding circuit board in which a metal circuit board is bonded to one surface of a ceramic substrate and a metal base plate for heat dissipation is bonded to the other surface. .

It is a perspective view which shows an example of the metal-ceramics junction circuit board manufactured by embodiment of the manufacturing method of the metal-ceramics junction circuit board by this invention. It is a top view of the metal-ceramics junction circuit board of FIG. 1A. It is IC-IC sectional view taken on the line of FIG. 1B. It is a perspective view of the casting_mold | template used for manufacture of the metal-ceramics junction circuit board of FIG. 1A-FIG. 1C. It is sectional drawing of the casting_mold | template of FIG. 2A. It is sectional drawing of the metal-ceramics junction board manufactured using the casting_mold | template of FIG. 2A-FIG. 2B. It is sectional drawing which shows the state which formed the resist so that the metal plate for a circuit of the metal-ceramics joint board | substrate of FIG. 3A and the surface of a metal base plate might be covered. It is a figure explaining the laser irradiation area | region formed in a ceramic substrate, in order to investigate the influence of the intensity | strength by the laser irradiation of the ceramic substrate of Examples 3-8. It is a figure explaining the measuring method of the 3 point | piece bending bending strength of the ceramic substrate of Examples 3-8 and the comparative example 3. FIG. It is a figure which shows the average value of the 3 point | piece bending bending strength of the ceramic substrate of Examples 3-8.

  In the embodiment of the method for manufacturing a metal / ceramic bonding circuit board according to the present invention, a circuit metal plate is bonded (directly) to one surface of the ceramic substrate, and a metal base plate for heat dissipation is (directly) bonded to the other surface. A bonded metal-ceramic bonding substrate is manufactured, a resist is formed so as to cover the surfaces of the circuit metal plate and metal base plate of the metal-ceramic bonding substrate, and the resist is unnecessary by irradiating the resist with laser light. After removing the portion, the exposed portions of the circuit metal plate and the metal base plate are etched so that the metal circuit plate is (directly) bonded to one surface of the ceramic substrate and the metal base is bonded to the other surface. A metal-ceramic bonding circuit board in which the plates are (directly) bonded is manufactured.

  According to the embodiment of the manufacturing method of the metal-ceramic bonding circuit board, for example, as shown in FIGS. 1A to 1C, a substantially rectangular shape of a rectangular shape smaller than the ceramic substrate 12 is formed on one surface of the substantially rectangular ceramic substrate 12. It is possible to manufacture the metal-ceramic bonding circuit board 10 in which the metal circuit board 14 is directly bonded and the substantially rectangular metal base plate 16 having a planar shape larger than the ceramic board 12 is directly bonded to the other surface of the ceramic board 12. it can.

  The metal-ceramic bonding circuit board 10 uses, for example, a mold 20 shown in FIGS. 2A to 2B, and a circuit board metal plate is directly bonded to one surface of the ceramic substrate and a metal base plate is bonded to the other surface. After the directly bonded metal-ceramic bonding substrate is manufactured, it can be manufactured by etching unnecessary portions of the circuit metal plate and the metal base plate.

  As shown in FIGS. 2A to 2B, the mold 20 includes a lower mold member 22 having a substantially rectangular plane shape, and a substantially flat upper mold member 24 as a lid of the lower mold member 22. ing. A recess (metal base plate forming portion) 22a for forming a metal base plate is formed on the bottom surface of the lower mold member 22, and a recess (ceramic substrate) for accommodating the ceramic substrate is formed on the bottom surface of the recess 22a. A housing portion 22b is formed, and a recess (circuit metal plate forming portion) 22c for forming a circuit metal plate is formed on the bottom surface of the recess 22b. The upper mold member 24 is formed with a pouring port 24 a for pouring molten metal into the mold 20. The lower mold member 22 is formed with a molten metal passage (runner passage) (not shown) extending between the metal base plate forming portion 22a and the circuit metal plate forming portion 22c, and is formed in the ceramic substrate housing portion 22b. The metal base plate forming portion 22a and the circuit metal plate forming portion 22c are in communication with each other even when the ceramic substrate is accommodated.

  The ceramic substrate 12 is placed inside the mold 20, a molten metal such as aluminum or aluminum alloy is poured into the mold 20, brought into contact with both surfaces of the ceramic substrate 12, and then cooled and solidified. When the ceramic bonded substrate is manufactured, as shown in FIG. 3A, the circuit metal plate 14 ′ is directly bonded to one surface of the ceramic substrate 12 and the metal base plate 16 is directly bonded to the other surface. The circuit metal plate 14 ′ and the metal base plate 16 are formed by a molten metal filled in a molten metal flow path (runner) extending between the metal base plate forming portion 22 a and the circuit metal plate forming portion 22 c of the mold 20. They are connected by the same metal, and it is necessary to etch away unnecessary portions such as the connecting portion 18.

  Therefore, in the embodiment of the method for producing a metal / ceramic bonding circuit board according to the present invention, as shown in FIG. 3B, the surfaces of the metal plate for circuit 14 ′ and the metal base plate 16 of the metal / ceramic bonding board are covered. By forming a resist 26 and irradiating the resist 26 with laser light, an unnecessary portion of the resist 26 (a portion corresponding to an unnecessary portion for forming the metal circuit board 14, a portion corresponding to the connecting portion 18, etc.) Then, portions where the surfaces of the circuit metal plate 14 ′ and the metal base plate 16 are exposed (such as a portion unnecessary for forming the metal circuit plate 14 and the connecting portion 18) are removed by etching.

  In the metal-ceramic bonding substrate, unlike the flat printed wiring board, the unevenness of the surface is large, so that the film thickness of the resist 26 becomes uneven at the edge portion of the metal base plate 16, and the subsequent steps The etching process cannot withstand chemicals and may cause etching defects.

  Therefore, in the embodiment of the method for manufacturing a metal / ceramic bonding circuit board according to the present invention, it is preferable that the edge portion of the metal base plate 16 is chamfered in an R shape before the resist 26 is formed. It is preferable to carry out so that it may become 15-5.0 mm, and it is still more preferable to carry out so that it may become R0.15-1.0 mm. In order to improve the dimensional accuracy of the metal circuit board 14 and the metal base plate 16 and to improve the adhesion of the resist 26 to the circuit metal plate 14 ′ and the metal base plate 16, before forming the resist 26, The surfaces of the circuit metal plate 14 ′ and the metal base plate 16 are preferably polished. The resist 26 is preferably formed by applying and curing a resist ink on the entire surface of the circuit metal plate 14 ′ and the metal base plate 16 by spray coating. In this case, it is preferable that the resist ink is an ultraviolet curable resist ink or an ant-kari removing resist ink containing an acrylic polymer. Furthermore, it is preferable to heat the metal / ceramic bonding substrate in advance before forming the resist.

  In addition, unlike a flat printed wiring board, a metal-ceramic bonding substrate has an uneven shape with a large step on the surface, so that resist ink is applied to the entire surface of the circuit metal plate 14 'and the metal base plate 16 by spray coating. When the resist 26 is formed so as to cover the surfaces of the circuit metal plate 14 ′ and the metal base plate 16, a laser is applied to the stepped portion between the edge surface of the ceramic substrate 12 and the metal base plate 16. It may be difficult to remove unnecessary portions of the resist 26 by irradiation. There are laser processing machines that have a function to focus on the work by moving the height of the work fixing base up and down so that it follows the uneven shape on the surface of the work. It takes a lot of time and effort to create 3D pattern data and input it to the laser processing machine.

  Therefore, as a method of removing unnecessary portions of the resist 26, a portion of the resist 26 formed so as to cover the upper surfaces of the circuit metal plate 14 ′ and the metal base plate 16 is covered with a plane covering the upper surface of the circuit metal plate 14 ′. A first region A that is a region; a second region B that is a planar region including a step covering the upper surface of the metal base plate 16; and an inclined surface between the first region A and the second region B. It is preferable to divide the laser beam into the third region C, which is a region, and adjust the depth of focus in the height direction of the laser beam for each region. In this case, the depth of focus of the laser beam in the height direction is the upper surface of the circuit metal plate 14 ′ in the first region A, the upper surface of the metal base plate 16 in the second region B, and the circuit depth in the third region C. It is preferable that the height of the upper surface of the metal plate 14 ′ and the upper surface of the metal base plate 16 are adjusted to be substantially intermediate. In this method, it is only necessary to create two-dimensional (coordinate) pattern data and input it to the laser processing machine, so it is easy to create and input pattern data, and create three-dimensional pattern data to the laser processing machine. The time required is 1/2 to 1/3 compared with the case of inputting.

  Moreover, it is preferable that laser beam irradiation is performed by a carbon dioxide laser irradiation apparatus or a Yb laser irradiation apparatus.

  Hereinafter, embodiments of the method for producing a metal / ceramic bonding circuit board according to the present invention will be described in detail.

[Example 1]
2A to 2B, a ceramic substrate made of AlN is accommodated in a ceramic substrate accommodating portion of a mold similar to the mold 20 shown in FIG. The metal base plate is directly bonded to one surface of the ceramic substrate and the circuit is connected to the other surface by filling the molten metal into the metal plate forming portion and then cooling to solidify the molten aluminum (so-called molten metal bonding method). A metal-ceramic bonding substrate in which the metal plate was directly bonded was manufactured.

  After the surfaces of the metal plate for circuit and metal base plate of the metal-ceramic bonding substrate manufactured in this way are mechanically polished and flattened, the surface of the metal plate for circuit and metal base plate (entire surface) is coated with acrylic resin. The etching resist ink is diluted with a diluent (propylene glycol monomethyl ether) to a dilution ratio of 6: 4 (resist ink: diluent), applied by a spray coater, and heated at 60 ° C. for 10 minutes in a warm air circulating oven to obtain resist ink. Was cured to form a resist having a thickness of 25 μm.

  Thus, a metal-ceramic bonding substrate having a resist formed on the surface (entire surface) of the circuit metal plate and the metal base plate is prepared, and two resists having a width of 1.6 mm are formed on the surface of the circuit metal plate by laser irradiation. The resist is irradiated with a laser with a 30 W output Yb laser (Keyence F300FAYb) to remove a predetermined portion of the resist so that one of the resist lines is formed. When the width of the resist line was measured at 15 points spaced at 1 mm intervals in the longitudinal direction, the minimum value was 1.60 mm, the maximum value was 1.70 mm, and the average value was 1.65 mm.

[Example 2]
A metal-ceramic bonding substrate having a resist formed on the surface (entire surface) of the circuit metal plate and metal base plate was prepared in the same manner as in Example 1 except that the resist thickness was 15 μm, and laser irradiation was performed. When the distance between two resist lines was measured at 15 points spaced apart by 1 mm in the longitudinal direction with respect to the resist lines formed by the above, the minimum value was 1.07 mm, the maximum value was 1.12 mm, and the average value was 1 0.09 mm.

[Comparative Example 1]
Screen printing is performed so that two resist lines having a width of 1.6 mm are formed at intervals of 1 mm by screen printing on the surface of the circuit metal plate of the metal-ceramic bonding substrate manufactured by the same method as in Example 1. The width of the resist line was measured at 15 points spaced apart by 1 mm in the longitudinal direction for one of the formed resist lines by moving the squeegee in parallel with the line. The minimum value was 1.66 mm and the maximum value was Was 1.71 mm, and the average value was 1.68 mm.

[Comparative Example 2]
Except that the squeegee of the screen printing machine was moved in the direction perpendicular to the line, the resist line was formed at 15 points spaced apart by 1 mm in the longitudinal direction for one of the formed resist lines by the same method as in Comparative Example 1. When the width was measured, the minimum value was 1.68 mm, the maximum value was 1.79 mm, and the average value was 1.75 mm.

  From the results of Examples 1-2 and Comparative Examples 1-2 described above, the linearity of the acrylic resist line formed by laser irradiation with a Yb laser as in Examples 1-2 is as in Comparative Examples 1-2. It was found that the linearity of the acrylic resist line formed by screen printing was equal to or better than that.

  Moreover, when the metal-ceramic bonding substrates of Examples 1-2 and Comparative Examples 1-2 were etched using a ferric chloride solution (specific gravity 1.4 g / mL) as an etching solution, Examples 1-2 were obtained. When the resist line was formed by laser irradiation as in the above and when the resist line was formed by screen printing as in Comparative Examples 1 and 2, there was no difference in line linearity due to etching.

[Example 3]
When the resist on the ceramic substrate is removed by laser irradiation, there is a possibility that the ceramic substrate may be irradiated with laser. Therefore, the influence of the strength of the ceramic substrate by laser irradiation was examined as follows.

  First, as shown in FIG. 4A, grooves 112a are formed vertically and horizontally by a mold so as to pass through the approximate center of one surface of an AlN substrate 112 of 90 mm × 80 mm × 0.6 mm as a ceramic substrate. After being divided into quarters as shown in (b), one of the divided ceramic substrates 112 ′ was output with a Yb laser of 30 W output (F300FAYb manufactured by Keyence Corporation) at an output of 40% and a scanning speed of 3000 mm / sec. A laser irradiation region 112′a having a line width of about 1 mm passing through the center line of the surface (a line width of about 1 mm was obtained by scanning 17 in parallel at a spot diameter of 60 μm) was formed.

  In this way, five ceramic substrates 112 ′ having the laser irradiation region 112′a formed thereon are prepared. As shown in FIG. 5, each ceramic substrate 112 ′ is placed with the laser irradiation region 112′a on the lower side. The upper fulcrum 122 is placed vertically on the opposite side (upper side) of the laser irradiation region 112′a of the ceramic substrate 112 ′ under measurement conditions of a load speed of 0.5 mm / min and a span distance of 30 mm on a pair of lower fulcrums 120. When the three-point bending strength was measured by loading so as to hit, the maximum value was 360 MPa, the minimum value was 331 MPa, and the average value was 346 MPa.

[Example 4]
Except that the output of the Yb laser was set to 30%, five ceramic substrates on which the laser irradiation region 112′a was formed were prepared in the same manner as in Example 3, and the three-point bending strength was measured. The maximum value was 530 MPa, the minimum value was 424 MPa, and the average value was 465 MPa.

[Example 5]
Except for setting the Yb laser output to 30% and the scan speed to 8000 mm / sec, five ceramic substrates on which the laser irradiation region 112'a was formed were prepared in the same manner as in Example 3, and three-point bending was performed. When the bending strength was measured, the maximum value was 563 MPa, the minimum value was 489 MPa, and the average value was 514 MPa.

[Examples 6 to 7]
Instead of a Yb laser, a CO ₂ laser with an output of 30 W (ML-Z9500 (wavelength 10.6 μm) manufactured by Keyence) was used, the laser output was 80%, and the scanning speed was 400 mm / second (Example 6). And 5 mm / sec (Example 7), except that the ceramic irradiation substrate 112′a was formed in the same manner as in Example 3, and the three-point bending strength was measured. However, in Example 6, the maximum value was 566 MPa, the minimum value was 536 MPa, the average value was 551 MPa, and in Example 7, the maximum value was 555 MPa, the minimum value was 532 MPa, and the average value was 546 MPa.

[Example 8]
A laser irradiation region 112'a having a line width of about 1 mm passing through the center line of one surface of the divided ceramic substrate (with a spot diameter of 60 μm (scanned like a ladder) and scanned to a line width of about 1 mm) was formed. Except for the above, in the same manner as in Example 7, five ceramic substrates on which the laser irradiation region 112′a was formed were prepared, and when the three-point bending strength was measured, the maximum value was 563 MPa, and the minimum value was 539 MPa. The average value was 551 MPa.

[Comparative Example 3]
Except for not forming the laser irradiation region 112′a, five ceramic substrates were prepared by the same method as in Example 3, and the three-point bending strength was measured. The maximum value was 569 MPa, and the minimum value was 532 MPa. The average value was 559 MPa.

The average value of the three-point bending strength of the AlN substrates of Examples 3 to 8 and Comparative Example 3 is shown in FIG. The three-point bending strength of the AlN substrate is preferably 300 MPa or more, more preferably 400 MPa or more, and most preferably 500 MPa or more. However, when laser irradiation is performed with a CO ₂ laser, The strength of the AlN substrate does not decrease.

  In addition, with respect to the metal / ceramic bonding substrate manufactured by the same method as in Example 1, the resist was irradiated with laser light under the same irradiation conditions as in the case of forming the laser irradiation region 112′a in Examples 3-8. However, the resist at the irradiated portion could be removed.

[Example 9]
2A to 2B, a ceramic substrate made of AlN is accommodated in a ceramic substrate accommodating portion of a mold similar to the mold 20 shown in FIG. The metal base plate is directly bonded to one surface of the ceramic substrate and the circuit is connected to the other surface by filling the molten metal into the metal plate forming portion and then cooling to solidify the molten aluminum (so-called molten metal bonding method). A metal-ceramic bonding substrate in which the metal plate was directly bonded was manufactured.

  The surface of the metal plate for circuit of the metal-ceramic bonding substrate thus manufactured and the surface of the metal base plate opposite to the bonding surface with the ceramic substrate are mechanically polished and flattened, and then the ceramic substrate of the metal base plate 4 sides (edge part) of the surface opposite to the joint surface with C are chamfered into an R shape (R0.2 mm by manual buffing), and heated (preheated) at 60 ° C. for 10 minutes in a hot air circulating oven. After that, an acrylic etching resist ink was diluted with a diluent (propylene glycol monomethyl ether) at a dilution ratio of 6: 4 (resist ink: diluted) to form a resist having a thickness of about 15 μm on the surface (entire surface) of the metal base plate. And is applied by spray coating, heated in a hot air circulating oven at 80 ° C. for 10 minutes to cure the resist ink, The thickness of the flat portion in the thickness of the section is 10 [mu] m (plane portion of the ceramic substrate opposite to side) to form a resist 20 [mu] m.

  In this way, four metal-ceramic bonding substrates having a resist formed on the entire surface of the metal base plate are prepared, and the resist on the surface of the metal base plate of each metal-ceramic bonding substrate is subjected to chloride at 35 ° C. as an etching solution. Ferric solution (specific gravity 1.4 g / mL) was sprayed for 10 minutes × 3 times, and the presence or absence of corrosion on the four sides (edge portions) on the opposite side of the ceramic substrate of the metal base plate was examined. When the number of corroded sides relative to the total number of sides (4 sides x 4) of the metal base plate of each metal-ceramic bonding substrate opposite to the ceramic substrate is the edge corrosion rate (%), the edge corrosion rate is 25%. Met. In this example, since buffing was performed manually, the edge chamfering of the edge portion of the metal base plate was uneven, and the edge corrosion rate was estimated to be 25%.

[Comparative Example 4]
4 pieces of resist in which the edge portion has a thickness of 2 μm and the planar portion has a thickness of 18 μm by the same method as in Example 9 except that the metal base plate is not chamfered and the edge portion has a substantially right angle. When the edge corrosion rate was examined, the edge corrosion rate was 100%.

[Comparative Example 5]
Four metal-ceramics having a resist formed in the same manner as in Example 9, except that the metal base plate is not chamfered and the edge portion is substantially perpendicular, and the resist ink dilution ratio is 5: 5, respectively. A bonded substrate was prepared and the edge corrosion rate was examined. The edge corrosion rate was 100%.

[Comparative Example 6]
Except that the metal base plate is not chamfered to have a substantially right edge portion, and the dilution ratio of the resist ink is 4: 6, respectively, the edge portion has a thickness of 2 μm and a flat portion by the same method as in Example 9. Four metal-ceramic bonding substrates on which a resist having a thickness of 23 μm was prepared and the edge corrosion rate was examined. The edge corrosion rate was 100%.

[Comparative Example 7]
A method similar to Example 9 except that the four sides of the metal base plate are chamfered instead of chamfering in a C shape (C0.25 by C cut), and the dilution ratio of the resist ink is set to 4: 6, respectively. Then, four metal-ceramic bonding substrates on which resists having an edge portion thickness of 2 μm and a planar portion thickness of 24 μm were prepared and the edge corrosion rate was examined. The edge corrosion rate was 94%. It was.

[Comparative Example 8]
The thickness of the edge portion was 3 μm and the thickness of the flat portion was the same as in Example 9, except that the preheating temperature was 80 ° C. and the metal base plate was not chamfered and the edge portion was substantially perpendicular. When four metal-ceramic bonding substrates on which a 15 μm resist was formed were prepared and the edge corrosion rate was examined, the edge corrosion rate was 50%.

[Comparative Example 9]
The resist was prepared in the same manner as in Example 9 except that the preheating temperature was 80 ° C., the metal base plate was not chamfered and the edge portion was substantially perpendicular, and the dilution ratio of the resist ink was 5: 5. When four formed metal-ceramic bonding substrates were prepared and the edge corrosion rate was examined, the edge corrosion rate was 75%.

[Comparative Example 10]
The edge portion was formed by the same method as in Example 9 except that the preheating temperature was 80 ° C., the edge portion was substantially perpendicular without chamfering the metal base plate, and the dilution ratio of the resist ink was 4: 6. 4 metal-ceramic bonding substrates on which a resist having a thickness of 7 μm and a planar portion of 20 μm was prepared, and the edge corrosion rate was examined. The edge corrosion rate was 88%.

  If the temperature of the metal / ceramic bonding substrate is preheated to 80 ° C. as in Comparative Examples 5 to 7, the solvent content of the resist ink is volatilized and the thixotropy increases in a short time after the sprayed resist ink is deposited. However, it was estimated that the film thickness remained adhered by spraying was maintained, but from the results of Comparative Examples 5 to 7, the resist film thickness at the edge of the metal base plate was several μm or less, and was resistant to etching. It is understood that it is necessary to sufficiently secure the resist film thickness at the edge portion of the metal base plate. On the other hand, if the edge portion of the metal base plate is chamfered in an R shape as in Example 9, the resist on the edge portion of the metal base plate can be thickened. In order to increase the thickness of the resist at the edge portion, it is preferable that the resist ink has a high viscosity.

[Examples 10 to 11, Comparative Example 11]
A resin-made cup brush mixed with abrasives is attached to a milling cutter, and the metal base plate is chamfered by wet machining under conditions of 3600 rpm and 250 mm / min (approximately 30 seconds per metal-ceramic bonding substrate). Example (R dimension: 0.2-0.3 mm) (Example 10) and R-shaped chamfering (R dimension: 0.4-0.6 mm) (Example 11) by dry processing. 10 metal-ceramic bonding substrates on which resists were formed by the same method as in No. 9, and the edge corrosion rate for four (Example 10) and six (Example 11) metal-ceramic bonding substrates, respectively. As a result, in all of Examples 10 and 11, the edge corrosion rate was 0%. In addition, except that the metal base plate was not chamfered and made a substantially right-angled edge portion, by preparing the three metal-ceramic bonding substrates by the same method as in Example 9, and examining the edge corrosion rate, The number of corroded sides was 9, and the edge corrosion rate was 75%.

DESCRIPTION OF SYMBOLS 10 Metal-ceramic bonding circuit board 10 'Metal-ceramic bonding board 12 Ceramic board 14 Metal circuit board 14' Circuit metal plate 16 Metal base plate 20 Mold 22 Lower mold member 22a Recessed part (metal base plate formation part)
22b Concave portion (ceramic substrate receiving portion)
22c Recess (Circuit metal plate forming part)
24 Upper mold member 24a Pouring port 26 Resist 112 Ceramic substrate (AlN substrate)
112a Groove 112 ′ Divided ceramic substrate 112 ′ a Laser irradiation area 120 Lower fulcrum 122 Upper fulcrum

Claims (12)

A metal-ceramic bonding substrate is manufactured in which a circuit metal plate is bonded to one surface of a ceramic substrate and a metal base plate is bonded to the other surface, and the circuit metal plate and the metal base plate of the metal-ceramic bonding substrate are manufactured. After forming a resist so as to cover the surface and irradiating this resist with a laser beam to remove unnecessary portions of the resist, etching the exposed portions of the circuit metal plate and the metal base plate, A method for producing a metal / ceramic bonding circuit board, comprising: producing a metal / ceramic bonding circuit board having a metal circuit board bonded to one surface of a ceramic substrate and a metal base plate bonded to the other surface. The metal-ceramic bonding substrate is a metal-ceramic bonding substrate in which the circuit metal plate is directly bonded to one surface of the ceramic substrate and the metal base plate is directly bonded to the other surface; The bonded circuit board is a metal-ceramic bonded circuit board in which the metal circuit board is directly bonded to one surface of the ceramic substrate and the metal base plate is directly bonded to the other surface. 2. A method for producing a metal / ceramic bonding circuit board according to 1. The metal-ceramic bonding substrate is manufactured by disposing the ceramic substrate in a mold, pouring a molten metal into the mold, bringing it into contact with both surfaces of the ceramic substrate, and then cooling and solidifying the metal substrate. The method for producing a metal / ceramic bonding circuit board according to claim 1 or 2, wherein: A resist portion formed so as to cover the upper surface of the circuit metal plate and the metal base plate, a first region which is a planar region covering the upper surface of the circuit metal plate, and an upper surface of the metal base plate The laser beam is divided into a second region, which is a planar region including a step to cover, and a third region, which is a region including an inclined surface between the first region and the second region. 4. The method of manufacturing a metal / ceramic bonding circuit board according to claim 3, wherein the laser beam is irradiated while adjusting a depth of focus in a height direction. The method for producing a metal / ceramic bonding circuit board according to any one of claims 1 to 4, wherein the laser beam irradiation is performed by a carbon dioxide laser irradiation device or a Yb laser irradiation device. 6. The method for producing a metal / ceramic bonding circuit board according to claim 1, wherein surfaces of the metal plate for circuit and the metal base plate are polished before forming the resist. 7. The method of manufacturing a metal / ceramic bonding circuit board according to claim 1, wherein an edge portion of the metal base plate is chamfered in an R shape before the resist is formed. The method for producing a metal / ceramic bonding circuit board according to claim 7, wherein the chamfering is performed so that R is 0.15 to 5.0 mm. 9. The resist according to claim 1, wherein the resist is formed by applying and curing a resist ink on the entire surface of the circuit metal plate and the metal base plate by spray coating. Manufacturing method of metal-ceramic bonding circuit board. The method for producing a metal / ceramic bonding substrate according to claim 9, wherein the metal / ceramic bonding substrate is heated in advance before forming the resist. 11. The method for producing a metal / ceramic bonding substrate according to claim 9, wherein the resist ink is an ultraviolet curable resist ink or an ant-removal type resist ink containing an acrylic polymer. 12. The method for producing a metal / ceramic bonding substrate according to claim 1, wherein the circuit metal plate and the metal base plate are made of aluminum or an aluminum alloy.

Images