JP2010056205A - Method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device with high dimensional accuracy capable of reducing the number of work steps and manufacturing at low cost and effectively discharging voids.
The present invention combines a plurality of first glass ceramic green sheets 11 to 15 and second glass ceramic green sheets 21 to 24 that start firing shrinkage at a temperature higher than the firing shrinkage end temperature. The step of producing the glass ceramic green sheet laminate 5, the step of laminating the heat sink 7 having a larger mass than the multilayer substrate 50 in which the through holes 71 for semiconductor mounting are formed, and the glass ceramic green on which the heat sink 7 is laminated A step of firing the sheet laminate 5 at a temperature at which the second glass ceramic green sheets 21 to 24 are fired and contracted and at which the heat sink 7 is not melted to produce a multilayer substrate 50 to which the heat sink 7 is bonded. And a step of mounting the semiconductor element 6 on the multilayer substrate 50 through the semiconductor mounting through hole 71.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a semiconductor device with high dimensional accuracy in which a semiconductor element and a heat sink are mounted on a multilayer substrate.

  2. Description of the Related Art A semiconductor device is known in which a semiconductor element and a heat sink are mounted on a multilayer substrate in which wiring layers and through conductors are provided inside an insulating substrate in which a plurality of insulating layers are stacked and connected to each other. (For example, refer to Patent Document 1).

  Here, as the multilayer substrate used in the semiconductor device, a substrate having high dimensional accuracy (accuracy of the interval between terminals formed on the main surface) in which shrinkage in the planar direction during firing is suppressed can be used.

  As a specific method for producing a multilayer substrate, a first glass ceramic green sheet, a second glass ceramic green sheet that starts firing shrinkage at a temperature higher than the firing shrinkage end temperature of the first glass ceramic green sheet, And forming a through hole in each glass ceramic green sheet and filling with a paste for through conductor, and applying a wiring layer conductor paste on one main surface of each glass ceramic green sheet to form a first glass ceramic A method of producing a glass ceramic green sheet laminate by combining a green sheet and a second glass ceramic green sheet, and firing the glass ceramic green sheet laminate at a temperature at which the second glass ceramic green sheet is fired and contracted. (For example, patent literature See.).

  According to such a manufacturing method, when the first glass ceramic green sheet is fired and shrunk, the shrinkage in the planar direction is suppressed by the second glass ceramic green sheet that has not started firing shrinkage. On the other hand, when the second glass ceramic green sheet is fired and shrunk, shrinkage in the planar direction is suppressed by the first glass ceramic green sheet in a state where the firing shrinkage has already been completed. Note that the shrinkage in the stacking direction increases as the shrinkage in the planar direction is suppressed. With the mechanism as described above, the dimensional accuracy (accuracy of the distance between the terminals formed on the main surface) of the multilayer substrate (the state after firing the glass ceramic green sheet laminate) is increased.

  However, according to this multilayer substrate manufacturing method, since the second glass ceramic green sheet starts firing shrinkage after the first glass ceramic green sheet finishes firing shrinkage, for example, the second glass ceramic green sheet Voids generated in the second glass ceramic green sheet are contained in the first insulating layer (first glass ceramic) when there are many inorganic compositions that are gasified at high temperatures, such as boron, and voids are likely to be generated. The state after the firing and shrinkage of the green sheet is blocked, and the place is not discharged to the outside, but remains near the boundary with the first insulating layer, resulting in a decrease in insulation reliability or delamination There was a problem that.

On the other hand, there has been proposed a method for producing a multilayer substrate with good dimensional accuracy by firing a glass ceramic green sheet laminate from above and below using a pressure application mechanism while effectively discharging voids ( (See Patent Document 3).
JP 2001-244362 A JP 2001-15875 A Japanese Patent No. 3363227

  However, according to the method described in Patent Document 3, special equipment for pressure firing is required, which is problematic in terms of equipment cost.

  Moreover, when manufacturing a semiconductor device using a multilayer substrate obtained by the method described in Patent Document 3, it is necessary to join a heat radiating member after mounting a semiconductor element, and the number of work steps cannot be reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor device with high dimensional accuracy that can reduce the number of work steps, can be manufactured at low cost, and can effectively discharge voids. .

  The present invention provides a method for manufacturing a semiconductor device in which a semiconductor element and a heat sink are mounted on an upper surface of a multilayer substrate. The first glass ceramic green sheet and a firing shrinkage end temperature of the first glass ceramic green sheet Forming a second glass ceramic green sheet that starts firing shrinkage at a high temperature, and forming a through hole in at least one of the first glass ceramic green sheet and the second glass ceramic green sheet; Filling the through-conductor paste, applying the wiring layer conductor paste to at least one main surface of the first glass ceramic green sheet and the second glass ceramic green sheet, and the first Glass ceramic green sheet and the second glass ceramic grease A step of producing a glass ceramic green sheet laminate by combining a plurality of sheets, and at least one opening is approximately the same size as the semiconductor element, and the one opening from the one opening to the other opening A through-hole for mounting a semiconductor having the same size or a larger cross section than that of the second glass ceramic green sheet, the melting temperature being higher than the firing shrinkage end temperature, and the heat dissipation plate having a mass larger than that of the multilayer substrate And the glass ceramic green sheet laminate in which the heat radiating plate is laminated, and a step of laminating through the bonding material such that the surface having the one opening portion faces the upper surface of the glass ceramic green sheet laminate. The temperature at which the second glass ceramic green sheet is fired and shrunk and the heat sink is not melted. And the step of fabricating the multilayer substrate to which the heat sink is bonded, and the step of mounting the semiconductor element on the multilayer substrate through the through hole for mounting a semiconductor. .

  Here, it is preferable that the semiconductor mounting through-hole has a shape that gradually increases from the one opening to the other opening.

  Further, in the method of manufacturing a semiconductor device, when the side surface of the semiconductor element is not in direct contact with the heat sink, the heat dissipation lid is attached to the upper surface of the semiconductor element and the heat sink after the semiconductor element is mounted. It is preferable to have the process closely_contact | adhered to.

  According to the present invention, a glass ceramic is produced by combining a first glass ceramic green sheet and a second glass ceramic green sheet that starts firing shrinkage at a temperature higher than the firing shrink end temperature of the first glass ceramic green sheet. Since the green sheet laminate is produced and fired, shrinkage in the planar direction is suppressed, and the dimensional accuracy of the multilayer substrate constituting the semiconductor device can be increased.

  Further, since the shrinkage in the planar direction of the glass ceramic green sheet laminate is suppressed, the melting temperature is higher than the firing shrinkage end temperature of the second glass ceramic green sheet, and the multilayer substrate (fired glass ceramic green sheet laminate) Even if a heat sink with a larger mass than the latter) is fired in a state where the heat sink is laminated on the glass ceramic green sheet laminate through the bonding material, the heat sink can be removed from the multilayer substrate, or cracks can be generated in the bonding material. There is little risk of doing so. Therefore, a heat sink can be laminated on the glass ceramic green sheet laminate and fired while applying a load by the heat sink. By firing in this way, the second glass ceramic green sheet is generated, The void accumulated in the vicinity of the boundary with the first insulating layer (the state after completion of the firing shrinkage of the first glass ceramic green sheet) can be effectively discharged by extruding from the center toward the periphery. .

  Further, the heat sink has a semiconductor mounting in which at least one opening is substantially the same size as the semiconductor element and has the same size or larger cross section as the one opening from the one opening to the other opening. And through the bonding material so that the surface having one opening is opposed to the upper surface of the glass ceramic green sheet laminate, the glass ceramic green sheet laminate and the heat sink The bonding area can be increased, the heat dissipation of the semiconductor device can be improved, and a substantially uniform load can be applied to all regions on the upper surface of the glass ceramic green sheet laminate.

  Furthermore, since the through hole for mounting a semiconductor gradually increases from one opening to the other, it is easy to fill the gap between the lower surface of the semiconductor element and the upper surface of the multilayer substrate. Become.

  Furthermore, when the side surface of the semiconductor element is not in direct contact with the heat radiating plate, the semiconductor element is mounted and adhered to the upper surface of the semiconductor element and the heat radiating plate after the semiconductor element is mounted. The heat dissipation effect of the heat generated in can be further enhanced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The present invention is a method of manufacturing a semiconductor device in which a semiconductor element and a heat sink are mounted on the upper surface of a multilayer substrate, and FIG. 1 is an explanatory view of an embodiment of the method of manufacturing a semiconductor device of the present invention. The state which has not mounted the semiconductor element is shown. 2 is an explanatory view of another embodiment of the method for manufacturing a semiconductor device of the present invention, FIG. 3 is an explanatory view of still another embodiment of the method for manufacturing a semiconductor device of the present invention, and FIG. 4 is a semiconductor of the present invention. It is explanatory drawing of further another embodiment of the manufacturing method of an apparatus.

  First, at a temperature higher than the firing shrinkage end temperature of the first glass ceramic green sheets 11, 12, 13, 14, 15 and the first glass ceramic green sheets 11, 12, 13, 14, 15 shown in FIG. Second glass ceramic green sheets 21, 22, 23, and 24 that start firing shrinkage are produced.

  Here, each green sheet is a glass ceramic green sheet because the firing temperature can be lowered, and a low melting point such as silver, copper or gold is used as a through-conductor paste 3 and a wiring layer conductor paste 4 described later. This is because a low-resistance metal can be used as a main component, and can sufficiently cope with high-speed and high-frequency signals.

  The first glass ceramic green sheets 11, 12, 13, 14, and 15 and the second glass ceramic green sheets 21, 22, 23, and 24 have different firing shrinkage start temperatures and firing shrinkage end temperatures. Specifically, the firing shrinkage start temperature of the second glass ceramic green sheets 21, 22, 23, 24 is higher than the firing shrinkage end temperature of the first glass ceramic green sheets 11, 12, 13, 14, 15. It is high. For example, the softening point of the glass contained in the second glass ceramic green sheets 21, 22, 23, 24 is greater than the crystallization point of the glass contained in the first glass ceramic green sheets 11, 12, 13, 14, 15. In this way, the firing shrinkage start temperature of the second glass ceramic green sheets 21, 22, 23, 24 is set to be higher than that of the first glass ceramic green sheets 11, 12, 13, 14, 15. It can be higher than the firing shrinkage end temperature. Note that the firing shrinkage start temperature here refers to the temperature at which volume shrinkage of 0.5% occurs when the target material is fired alone. The term “firing shrinkage end temperature” refers to a temperature at which volume shrinkage of 90% or more is achieved with respect to the amount of shrinkage from the state before firing to the state after finish of firing. Volume shrinkage is determined by converting from linear shrinkage of TMA (thermomechanical analysis) to volume shrinkage.

  As a raw material for producing the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24, firing shrinkage is performed at a low temperature of less than 1000 ° C. It is preferable to use what was prepared in the ratio of 30-100 mass% of glass powder, and 0-70 mass% of ceramic powder so that it can do.

The glass powder contains SiO ₂ and contains at least one of Al ₂ O ₃ , B ₂ O ₃ , ZnO, PbO, alkaline earth metal oxide, and alkali metal oxide, For example _SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O 3 _based, SiO ₂ -B ₂ O 3 _{-MO-based, SiO 2 -B 2 O 3 -Al} 2 O 3 system -MO Examples thereof include borosilicate glass such as a system (where M represents Ca, Sr, Mg, Ba, or Zn), alkali silicate glass, Ba-based glass, Pb-based glass, Bi-based glass, and the like. These glasses include, for example, lithium silicate, quartz, cristobalite, enstatite, cordierite, mullite, ananosite, serdian, spinel, garnite, willemite, dolomite, petalite, diopside and their substitution after firing. Examples thereof include crystalline glass in which at least one type of derivative crystal is precipitated, and amorphous glass that does not precipitate crystals after firing may be used in relation to the amount of ceramic powder blended.

Specifically, as the glass powder used for the first glass ceramic green sheets 11, 12, 13, 14, and 15, for example, Si is made of SiO ₂ in order to start firing shrinkage at a low temperature and to precipitate a large number of crystals. 1 to 30% by mass in terms of conversion, 5 to 25% by mass in terms of Al ₂ O ₃ , 25 to 60% by mass in terms of MgO, 0 to 10% by mass in terms of CaO, 0 in terms of BaO 20 wt%, 5-25 wt% of B in terms _{of B} 2 _{O 3,} 0-10 wt% of P in terms _{of P} 2 _{O 5,} 0 to 10 mass% of Sn in terms of SnO _2, the Na _Na 2 O What contains 0-3 mass% in conversion is mentioned.

The glass powder used for the second glass ceramic green sheets 21, 22, 23, and 24 is the second glass after completion of the firing shrinkage of the first glass ceramic green sheets 11, 12, 13, 14, and 15. For example, Si is converted to SiO ₂ in an amount of 25 to 45% by mass, Al is converted to Al ₂ O ₃ in an amount of 10 to 25% by mass, and Mg is converted to MgO so that the ceramic green sheets 21, 22, 23, and 24 start firing shrinkage. 10 to 24% by mass, B is 5 to 20% by mass in terms of B ₂ O ₃ , Zn is 5 to 20% by mass in terms of ZnO, and Ca is 0.5 to 4% by mass in terms of CaO. It is done.

As the ceramic powder, quartz, and SiO ₂ of _{cristobalite, Al 2 O 3, ZrO 2} , cordierite, mullite, forsterite, enstatite, spinel, magnesia or the like is used. Of these, it is preferable to use alumina from the viewpoint of increasing strength, reducing cost, and quartz from the viewpoint of increasing thermal expansion.

  A predetermined amount of the above-mentioned raw material powder is weighed, and an organic binder, an organic solvent, and optionally a plasticizer are added to prepare a slurry, which is then formed into a sheet by a known forming method such as a doctor blade method, a rolling method, or a pressing method. The first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24 having a thickness of 10 to 500 μm are produced.

  Next, a through hole is formed in at least one of the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24. 3 is filled.

  Further, the wiring layer conductor paste 4 is applied to at least one main surface of the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24. .

  Formation of a through hole in at least one of the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24 is performed by a method such as punching, laser, or etching. Etc. The through-conductor paste 3 filled in the through-hole is obtained by kneading an organic binder and an organic solvent into silver powder, copper powder, gold powder or the like as a main component, and further, if necessary, electric resistance, thermal conductivity. Insofar as it does not deteriorate, other metals, glass, oxides, carbides and nitrides may be included. For the filling, a screen printing method is used by using a metal mask or an emulsion mesh screen mask perforated at a position corresponding to the through hole. At this time, as a method of extruding the through-conductor paste 3 through the mask, a method using a plate-like (or sword-like) squeegee such as a normal polyurethane may be used. A method of injecting 3 under pressure may be used.

  Also, the application of the wiring layer conductor paste 4 to at least one of the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24 is performed by screen printing. This is done by law. As the conductor paste 4 for the wiring layer, similar to the paste 3 for the through conductor, an organic binder and an organic solvent are kneaded with silver powder, copper powder, gold powder or the like as the main component. As long as resistance and thermal conductivity are not deteriorated, other metals, glass, oxides, carbides, nitrides, and other inorganic components may be included. The wiring layer conductor paste 4 used here may have a viscosity different from that of the through conductor paste 3 filled in the through holes by means of, for example, varying the amount of the organic solvent. By making the viscosity lower than that of the through-conductor paste 3, the thickness can be reduced and an accurate pattern can be formed. In contrast, the through-conductor paste 3 can be prevented from dripping after filling by increasing the viscosity. Furthermore, the wiring layer conductor paste 4 and the through conductor paste 3 may have different main components and subcomponents such as glass and inorganic filler.

  The first glass ceramic green sheets 11, 12, 13, 14 and the second glass ceramic green sheets 21, 22, 23 are filled after the through conductor paste 3 is filled and the wiring layer conductor paste 4 is applied. Is dried at 60 to 100 ° C. for about 0.5 to 3 hours.

  Next, a plurality of first glass ceramic green sheets 11, 12, 13, 14, 15 and a plurality of second glass ceramic green sheets 21, 22, 23, 24 are combined to produce a glass ceramic green sheet laminate 5.

  For the lamination, a method in which heat and pressure are applied to the stacked first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24 by thermocompression bonding. A method of applying an adhesive composed of an organic binder, an organic solvent, a plasticizer, or the like between the sheets can be employed. In addition, in terms of the firing shrinkage suppression effect by the mutual glass ceramic green sheets, as shown in FIG. 1, the first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, A configuration in which 22, 23, and 24 are alternately stacked is desirable, but not limited to this form. For example, the first glass ceramic green sheets 11 to 14 may be stacked so that two or three layers continuously overlap each other. Also good. Also, the arrangement of the first glass ceramic green sheet and the second glass ceramic green sheet shown in FIG. 1 may be exchanged, and the second glass ceramic green sheet may be arranged on the surface layer. A similar void discharge effect can be obtained.

  The first glass ceramic green sheets 11, 12, 13, 14, 15 and the second glass ceramic green sheets 21, 22, 23, 24 are laminated in combination to form a first low firing shrinkage start temperature. When the glass ceramic green sheets 11, 12, 13, 14, 15 are fired and shrunk, the second glass ceramic green sheets 21, 22, 23, 24 in an unfired shrunken state are suppressed from shrinking in the planar direction, and fired. When the second glass ceramic green sheets 21, 22, 23, 24 having a high shrinkage start temperature are fired and shrunk, the first glass ceramic green sheets 11, 12, 13, 14, which have already finished firing shrinkage, 15, the shrinkage in the plane direction is suppressed. Thereby, the dimensional accuracy of the multilayer substrate 50 (the state after firing the glass ceramic green sheet laminate 5) constituting the semiconductor device is increased. Here, high dimensional accuracy means that the interval between the terminals formed on the main surface is formed with high accuracy. Note that the shrinkage in the stacking direction increases as the shrinkage in the planar direction is suppressed.

  Next, a semiconductor in which at least one opening 711 is substantially the same size as the semiconductor element 6 and has the same size or larger cross section as one opening 711 from one opening 711 to the other opening 712. A heat sink 7 having a mounting through-hole 71, a melting temperature higher than the firing shrinkage end temperature of the second glass ceramic green sheets 21, 2, 23, 24 and a mass larger than that of the multilayer substrate 50, Lamination is performed via the bonding material 8 so that the surface having the opening 711 faces the upper surface of the glass ceramic green sheet laminate 5.

  Here, the heat radiating plate 7 is a plate-like body made of a material that has good heat conduction and does not melt at a temperature at which the second glass ceramic green sheets 21, 22, 23, and 24 finish firing shrinkage. It is. As a material for forming the heat sink 7, a Cu—W alloy which is an alloy of Cu having a melting point of 1083 ° C. and W having a melting point of 3410 ° C., a Cu—Mo alloy which is an alloy of Cu having a melting point of 1083 ° C. and Mo having a melting point of 2620 ° C., etc. Is mentioned. For example, the heat-radiating plate 7 having a desired shape can be formed by melting this forming material, injecting it into a mold and cooling it. In addition, it is preferable that the ratio of Cu here is 10-60 mass%, and even if there are many ratios of Cu, by using high melting point W and Mo as an aggregate, it becomes by the baking temperature of 800-1000 degreeC. Can also retain its shape.

  The heat sink 7 has a larger mass than the multilayer substrate 50 (the state after the glass ceramic green sheet laminate 5 is fired). Since the heat sink 7 and the multilayer substrate 50 are in such a mass relationship, when the heat sink 7 is laminated on the glass ceramic green sheet laminate 5 and fired, the glass ceramic green sheet laminate 5 is sufficient. A load can be applied. In order to obtain such a mass, the forming material (mixing ratio of the alloy) of the heat sink 7, the area and thickness of the main surface may be adjusted, and the main surface of the heat sink 7 is made of the glass ceramic green sheet laminate 5. It may be larger than the main surface.

  In addition, at least one opening 711 is substantially the same size as the semiconductor element 6 in the heat sink 7, and the same size or larger crossing from one opening 711 to the other opening 712 as one opening 711. A semiconductor mounting through hole 71 having a surface is formed.

  This through hole 71 for semiconductor mounting is formed to secure a mounting region for the semiconductor element 6, and when the heat sink 7 is joined to the upper surface of the glass ceramic green sheet laminate 5, the glass ceramic green sheet is formed. The semiconductor element 6 is mounted in a region seen from above through the semiconductor mounting through hole 7 on the upper surface of the multilayer body 5.

  Here, as the shape of the through hole 71 for semiconductor mounting, one opening 711 is almost the same size as the semiconductor element 6 and the same size as one opening 711 from one opening 711 to the other opening 712. 2 is effective in that the mass of the heat radiating plate 7 can be increased and the load can be applied as evenly as possible. Further, the side surface of the semiconductor element 6 and the through holes 71 for mounting the semiconductor in the heat radiating plate 7 are effective. It is effective in that a high heat dissipation effect can be obtained by bringing the side wall into contact with each other. In the structure shown in FIG. 1, when underfill is injected between the semiconductor element 6 and the multilayer substrate 50, a notch for underfill injection is provided on the side wall of the semiconductor mounting through hole 71 from the upper surface to the lower surface. Just keep it. Although not shown, the thickness of the heat radiating plate 7 shown in FIG. 1 may be larger than the thickness of the semiconductor element 6, and as the thickness of the heat radiating plate 7 increases, the volume increases and the heat radiating effect increases. . Further, a plurality of fins may be provided on the upper surface side of the heat sink 7.

  Note that “substantially the same size” means that when the semiconductor element 6 is mounted, there may be a gap of 1 mm or less around the semiconductor element 6, and this gap is determined by the material and size of the heat sink 7. It adjusts suitably according to the heat dissipation effect.

  And the heat sink 7 is laminated | stacked through the bonding | jointing material 8 so that the surface which has one opening part 711 may oppose the upper surface of the glass ceramic green sheet laminated body 5. FIG.

  Examples of the bonding material 8 include a conductive paste made by kneading an organic binder and an organic solvent with silver powder, copper powder, or gold powder as a main component, or a solder such as silver solder or nickel solder having a melting point lower than that of the heat sink 7. Materials. For example, in the case of silver brazing, by adjusting the composition ratio of silver, copper, zinc, etc., it can be adjusted to withstand in the range of 650 to 900 ° C., and can be adapted to the case of a low firing temperature.

  Next, the glass ceramic green sheet laminate 5 on which the heat radiating plate 7 is laminated is fired at a temperature at which the second glass ceramic green sheets 21, 22, 23, and 24 are baked and contracted and the heat radiating plate 7 is not melted. Thus, the multilayer substrate 50 to which the heat radiating plate 7 is bonded is manufactured.

  When using the material of the present embodiment, specific firing is performed at a maximum firing temperature of 800 to 1000 ° C., particularly 850 to 850, from the viewpoint of sufficiently sintering the glass ceramic green sheet laminate 5 and preventing oversintering. 950 ° C. In firing, the temperature inside the furnace is temporarily maintained at a temperature lower than the firing shrinkage start temperature of the second glass ceramic green sheets 21, 22, 23, 24 until the maximum firing temperature is reached. Temperature management such as is done. The firing atmosphere is preferably a non-oxidizing atmosphere in order to prevent oxidation of the heat sink 7. Prior to firing, the glass ceramic green sheet laminate 5 is heat-treated at 400 to 750 ° C. to decompose and remove organic components in the glass ceramic green sheet laminate 5.

  Here, since the shrinkage in the planar direction of the glass ceramic green sheet laminate 5 is suppressed, even if the heat sink 7 is fired in a state where it is laminated on the glass ceramic green sheet laminate 5 with a bonding material, the multilayer substrate Therefore, there is little risk that the heat sink will be removed and cracks will occur in the bonding material. Therefore, by firing in this way, it is generated in the second glass ceramic green sheet, and its place is blocked by the first insulating layer (the state after the firing shrinkage of the first glass ceramic green sheet). It is possible to effectively discharge the void. Here, the void is effectively discharged because the load by the heat radiating plate 7 acts to push out the void from the center of the glass ceramic green sheet laminate 5 toward the periphery. When the second glass ceramic green sheets 21, 22, 23, and 24 start firing shrinkage, the first glass ceramic green sheets 11, 12, 13, 14, and 15 are already fired shrinkage and solidified. Therefore, even under the through hole 71 for mounting the semiconductor element, it is considered that a load is applied almost evenly.

  Next, the semiconductor element 6 is mounted on the multilayer substrate 50 through the semiconductor mounting through hole 71. The heat sink 7 has at least one opening 711 that is substantially the same size as the semiconductor element 6 and has the same size or larger cross section as the one opening 711 from one opening 711 to the other opening 712. Since the semiconductor mounting through-hole 71 is provided, and the surface having one opening 711 is laminated via the bonding material 8 so as to face the upper surface of the glass ceramic green sheet laminate 5, the heat sink 7 The semiconductor element 6 can be mounted after the bonding.

  Specifically, a connection terminal (not shown) formed on the upper surface of the multilayer substrate 50 and a connection terminal (not shown) formed on the lower surface of the semiconductor element 6 are joined together by solder (not shown). Is implemented.

  The heat radiating plate 7 in the present invention is not limited to the form shown in FIG. 1. For example, as shown in FIG. 2, the semiconductor mounting through-hole 71 gradually extends from one opening 711 to the other opening 712. It may be a shape that becomes larger, in other words, a shape that gradually expands. In the case of this shape, it becomes easy to fill the gap between the lower surface of the semiconductor element 6 and the upper surface of the multilayer substrate 50 with an underfill. In the case of this form, the heat from the semiconductor element 6 is transmitted to the heat radiating plate 7 mainly through the multilayer substrate 50.

  Further, as shown in FIG. 3, the heat sink 7 is thicker than the thickness of the semiconductor element 6, and the shape in which the cross section of the semiconductor mounting through-hole 71 changes midway, specifically, the thickness of the semiconductor element 6 is almost the same. The cross section of the region at a higher position may be larger than the cross section of the region up to the same height. Furthermore, as shown in FIG. 4, the heat dissipation plate 7 may be thicker than the semiconductor element 6, and the semiconductor mounting through hole 71 may gradually expand from one opening 711 to the other opening 712. .

  After mounting the semiconductor element 6, as shown in FIGS. 3 and 4, it is generated in the semiconductor element 6 by adhering and fixing the radiating lid 9 to the upper surface of the semiconductor element 6 and the radiating plate 7. The heat radiation effect can be further enhanced. In particular, when the side surface of the semiconductor element 6 as shown in FIGS. 3 and 4 is not in direct contact with the heat radiating plate 7, after the semiconductor element 6 is mounted, the heat radiating lid 9 is attached to the upper surface of the semiconductor element 6. And the heat radiating plate 7 are preferably in close contact with each other because the heat radiation effect of the heat generated in the semiconductor element 6 can be further enhanced.

  Since the heat dissipation lid 9 is attached after firing, it is not necessary to pay particular attention to the melting temperature, and Cu, Al, etc. can be employed from the viewpoint of thermal conductivity. However, in consideration of the difference in thermal expansion from the heat sink 7, it is preferable to use a material formed of the same material as the heat sink 7.

  Further, for fixing the radiating lid 9 to the radiating plate 7, for example, a method of joining with a conductive paste mainly composed of copper, silver or gold or a brazing material such as silver brazing or nickel brazing is adopted. In some cases, it is not necessary to join all surfaces. For example, in the form shown in FIG. 3, it may be joined to the heat radiating plate 7 only on the side surface or the lower surface of the heat radiating lid body 9, and in the form shown in FIG.

As raw material powder of the first glass ceramic green sheet, 15% by mass of quartz powder and 85% by mass of glass powder were used. The composition of the glass powder, 15 wt% of Si in terms of SiO _2, 2% by weight of Al in terms _{of Al} 2 _{O 3,} 40 wt% of Mg in terms of MgO, 1% by mass of Ca in terms of CaO, BaO converted Ba 15% by mass, B is 20% by mass in terms of B ₂ O ₃ , Zn is 1% by mass in terms of ZnO, Ti is 0.5% by mass in terms of TiO ₂ , and Na is 0.5% by mass in terms of Na ₂ O , Li is 5% by mass in terms of Li ₂ O.

On the other hand, as a raw material powder of the second glass ceramic green sheet, 45% by mass of quartz powder and 55% by mass of glass powder were used. The composition of the glass powder, 50 wt% of Si in terms of SiO _2, 5 wt% of Al in terms _{of Al} 2 _{O 3,} 20 wt% of Mg in terms of MgO, 24 wt% of Ca in terms of CaO, BaO converted Ba 0.5% by mass, B is 0.3% by mass in terms of B ₂ O ₃ , and Li is 0.2% by mass in terms of Li ₂ O.

  Then, a slurry is prepared by adding an acrylic binder as an organic binder and toluene as an organic solvent to each raw material powder, and a first glass having a thickness of 10 μm on a polyethylene terephthalate film (PET film) by a doctor blade method. A ceramic green sheet was produced, and a second glass ceramic green sheet having a thickness of 100 μm was produced on the PET film.

  Thereafter, after the first glass ceramic green sheet and the second glass ceramic green sheet are overlaid, the PET film is peeled off, and the composite glass composed of the first glass ceramic green sheet and the second glass ceramic green sheet A ceramic green sheet was prepared.

  A through hole is formed in the first glass ceramic green sheet and the composite glass ceramic green sheet by punching, and the through conductor paste is filled in the through hole, and the wiring layer conductor paste is applied to the main surface by screen printing. . Here, Cu powder, ethyl cellulose as an organic binder, and 2-2-4-trimethyl-3-3-pentadiol monoisobutyrate as an organic solvent are used as forming materials for the through conductor paste and the wiring layer conductor paste. An added paste was used.

  Then, the first glass ceramic green sheet and the composite glass ceramic green sheet are combined, and the first glass ceramic green sheet and the second glass ceramic green sheet are alternately laminated. A glass ceramic green sheet laminate in which 31 layers of the first glass ceramic green sheet and 30 layers of the second glass ceramic green sheet were laminated so as to be arranged in the outer layer and the planar shape was 5 cm square was produced.

  Next, on the upper surface of the glass ceramic green sheet laminate, a heat sink (4.8 cm) having a through hole for mounting a semiconductor having a cross section substantially the same as the size of the semiconductor element (1.5 cm square) as shown in FIG. 1 mm thick at the corners) were joined and laminated with a conductor paste mainly composed of copper. Here, the heat sink used was a Cu-W alloy having 20 mass% Cu and 80 mass% W.

  The glass ceramic green sheet laminate with the heat sink laminated on the upper surface and the glass ceramic green sheet laminate without the heat sink laminated on the upper surface are held in a nitrogen atmosphere at 700 ° C. for 2 hours for binder removal treatment. After that, firing was performed at a firing maximum temperature of 900 ° C.

  In addition, mass ratio of the heat sink after baking and the multilayer substrate (state after baking of the glass ceramic green sheet laminated body) was 2: 1.

  About each obtained sample, a cross section was grind | polished, the SEM photograph of 1000 time was image | photographed using the scanning microscope (SEM), and the 2nd 2nd insulating layer (2nd from the top was used using the image analyzer. Near the boundary with the second first insulating layer (the state after firing the first glass ceramic green sheet) from the top (the state after firing of the glass ceramic green sheet) of 20 μm from the interface with the first insulating layer The void ratio in the region) was measured.

  As a result, the void ratio of the multilayer board without the heat sink is 20%, whereas the void ratio of the multilayer board with the heat sink is 8%. It was confirmed that can be discharged.

  Further, when a semiconductor element was mounted on a multilayer substrate on which heat sinks were laminated and measured using a thermography, it was confirmed that the heat dissipation effect was sufficient.

It is explanatory drawing of one Embodiment of the manufacturing method of the semiconductor device of this invention, and has shown the state which is going to mount a semiconductor element. It is explanatory drawing of other embodiment of the manufacturing method of the semiconductor device of this invention, and has shown the state after mounting a semiconductor element. It is explanatory drawing of other embodiment of the manufacturing method of the semiconductor device of this invention, and has shown the state after mounting a semiconductor element. It is explanatory drawing of further another embodiment of the manufacturing method of the semiconductor device of this invention, and has shown the state after mounting a semiconductor element.

Explanation of symbols

11, 12, 13, 14, 15 ... 1st glass ceramic green sheet 21, 22, 23, 24 ... 2nd glass ceramic green sheet 3 ... Paste for penetration conductors 4 ... Wiring layer Conductive paste 5 ... Glass ceramic green sheet laminate 50 ... Multilayer substrate 6 ... Semiconductor element 7 ... Heat sink 71 ... Semiconductor mounting through hole 711 ... One opening 712. .... Other opening 8 ... Joint material 9 ... Heat dissipation lid

Claims (3)

In a method for manufacturing a semiconductor device in which a semiconductor element and a heat sink are mounted on an upper surface of a multilayer substrate,
Producing a first glass ceramic green sheet and a second glass ceramic green sheet that starts firing shrinkage at a temperature higher than the firing shrink end temperature of the first glass ceramic green sheet;
Forming a through hole in at least one of the first glass ceramic green sheet and the second glass ceramic green sheet, and filling a through conductor paste;
Applying a wiring layer conductor paste to at least one principal surface of the first glass ceramic green sheet and the second glass ceramic green sheet;
Producing a glass ceramic green sheet laminate by combining a plurality of the first glass ceramic green sheets and the second glass ceramic green sheets;
A semiconductor mounting through-hole having at least one opening having substantially the same size as the semiconductor element and having the same size or a larger cross section as the one opening from the one opening to the other opening. A heat sink having a melting temperature higher than the firing shrinkage end temperature of the second glass ceramic green sheet and a mass larger than that of the multilayer substrate, and the surface having the one opening is the glass ceramic green sheet laminate. Laminating via a bonding material so as to face the upper surface of
The glass ceramic green sheet laminate on which the heat sink is laminated is fired at a temperature at which the second glass ceramic green sheet is fired and contracted and the heat sink is not melted, and the heat sink is joined. Producing the multilayer substrate;
And a step of mounting the semiconductor element on the multilayer substrate through the semiconductor mounting through hole. The method of manufacturing a semiconductor device according to claim 1, wherein the through hole for mounting a semiconductor has a shape that gradually increases from the one opening to the other opening. The side surface of the semiconductor element is not in direct contact with the heat radiating plate, and after the semiconductor element is mounted, the method includes a step of closely attaching a heat radiating lid to the upper surface of the semiconductor element and the heat radiating plate. A method of manufacturing a semiconductor device according to claim 1 or 2.

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