GB2327150A - Composite substrate for a heat-generating semiconductor device - Google Patents
Composite substrate for a heat-generating semiconductor device Download PDFInfo
- Publication number
- GB2327150A GB2327150A GB9823805A GB9823805A GB2327150A GB 2327150 A GB2327150 A GB 2327150A GB 9823805 A GB9823805 A GB 9823805A GB 9823805 A GB9823805 A GB 9823805A GB 2327150 A GB2327150 A GB 2327150A
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- United Kingdom
- Prior art keywords
- composite
- layer
- metal
- composite substrate
- semiconductor device
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Links
- 239000002131 composite material Substances 0.000 title claims abstract description 234
- 239000000758 substrate Substances 0.000 title claims abstract description 139
- 239000004065 semiconductor Substances 0.000 title claims abstract description 118
- 229910052751 metal Inorganic materials 0.000 claims abstract description 133
- 239000002184 metal Substances 0.000 claims abstract description 133
- 239000000463 material Substances 0.000 claims abstract description 57
- 239000006185 dispersion Substances 0.000 claims abstract description 33
- 239000011159 matrix material Substances 0.000 claims abstract description 30
- 229910000679 solder Inorganic materials 0.000 claims abstract description 21
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 7
- 229910052802 copper Inorganic materials 0.000 claims abstract description 7
- 239000010949 copper Substances 0.000 claims abstract description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000005219 brazing Methods 0.000 claims abstract description 6
- 238000005266 casting Methods 0.000 claims abstract description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000000919 ceramic Substances 0.000 claims abstract description 3
- 238000005476 soldering Methods 0.000 claims description 17
- 230000017525 heat dissipation Effects 0.000 claims description 13
- 229910000838 Al alloy Inorganic materials 0.000 claims description 7
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 3
- 230000007423 decrease Effects 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 238000010030 laminating Methods 0.000 claims 1
- 229910045601 alloy Inorganic materials 0.000 abstract description 3
- 239000000956 alloy Substances 0.000 abstract description 3
- 239000004411 aluminium Substances 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 159
- 238000010276 construction Methods 0.000 description 20
- 239000000835 fiber Substances 0.000 description 11
- 206010040844 Skin exfoliation Diseases 0.000 description 9
- 238000005336 cracking Methods 0.000 description 9
- 230000008646 thermal stress Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 7
- 230000004048 modification Effects 0.000 description 7
- 229910010293 ceramic material Inorganic materials 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910018125 Al-Si Inorganic materials 0.000 description 3
- 229910018520 Al—Si Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000035882 stress Effects 0.000 description 3
- -1 Forstellite Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 230000005496 eutectics Effects 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- QYEXBYZXHDUPRC-UHFFFAOYSA-N B#[Ti]#B Chemical compound B#[Ti]#B QYEXBYZXHDUPRC-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910006776 Si—Zn Inorganic materials 0.000 description 1
- 229910020994 Sn-Zn Inorganic materials 0.000 description 1
- 229910009069 Sn—Zn Inorganic materials 0.000 description 1
- 229910033181 TiB2 Inorganic materials 0.000 description 1
- 229910007948 ZrB2 Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- VWZIXVXBCBBRGP-UHFFFAOYSA-N boron;zirconium Chemical compound B#[Zr]#B VWZIXVXBCBBRGP-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 210000001170 unmyelinated nerve fiber Anatomy 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
- H01L23/3733—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the groups H01L21/18 - H01L21/326 or H10D48/04 - H10D48/07
- H01L21/4814—Conductive parts
- H01L21/4871—Bases, plates or heatsinks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0058—Laminating printed circuit boards onto other substrates, e.g. metallic substrates
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
A composite substrate 1 on which a heat-generating semiconductor device 7 is to be mounted, comprises a composite layer 2, which includes a matrix 5 made of a metal having a high thermal conductivity and a fibrous or particulate ceramic dispersion material 4 having low thermal expansion properties, and a metal layer 3 bonded by a brazing material or solder 10 to one main surface of the composite layer. The heat-generating semiconductor device 7 for a substrate 8 with low thermal expansion properties having the heat-generating semiconductor device provided thereon, is mounted on the other main surface of the composite layer, possibly via solder 6 and a metal film 9. The metal matrix 5 and the metal layer 3 may be aluminium or copper or alloys thereof. The composite substrate may be formed by pressure casting.
Description
COMPOSITE SUBSTRATE FOR HEAT-GENERAT1NG SEMICONDUCTOR DEVICE AND SEMICONDUCTOR
APPARATUS USING THE SAME
The present application is divided from UK Application 9705237 7 (Serial No. 2311414), the "parent case".
BACKGROUND OF THE INVENTION
The present invention relates to a composite substrate which has excellent heatdissipating properties (or heat-absorbing properties) and is suitable for a substrate with a semiconductor device generating heat mounted thereon. The present invention also relates to a semiconductor apparatus employing the composite substrate.
Recently, with the development of large-scale semiconductor devices and the increase of the integration density, the amount of heat generated from the semiconductor devices has increased. To prevent thermal distortion, the substrate, on which the semiconductor device generating heat is mounted, (hereinafter, referred to as "heat-generating semiconductor device") must have a small thermal expansion coefficient close to that of the semiconductor device. To increase heat dissipation, the substrate must have an excellent thermal conductivity.
As a material for the substrate having a small thermal expansion coefficient, a ceramic material and a metal material are known. Examples of the ceramic material include alumina, Forstellite, mullite, and the like. Examples of the metal material include an Fe-Co alloy such as Koval, a Ni alloy such as 42
Alloy, and the like. However, these materials have a problem in that they have low thermal conductivities. On the other hand, as a material for the substrate having a high thermal conductivity, copper, copper alloys, aluminum, aluminum alloys and the like are generally known. However, these materials have a problem in that they have large thermal expansion coefficients.
Hence, the conventional semiconductor apparatuses employ a composite substrate which comprises a board having a small thermal expansion coefficient and a board having a good thermal conductivity, both being bonded with a solder having a low melting point. A heat-generating semiconductor device is usually mounted on the side of the board having a small thermal expansion coefficient of the composite substrate.
However, the conventional composite substrate has the following problems. Since the composite substrate is formed of two heterogeneous materials quite different in properties, high bonding strength is hardly obtained. Crackings or peelings are likely to take place at the bonding portion of the composite substrate when the bonding portion repeatedly receives thermal stress due to heat generation from the semiconductor device. As a result, the heat dissipation properties are deteriorated. Furthermore, since the board, on which the heat generating semiconductor device is mounted, is poor in thermal conductivity, the heat dissipation properties of the composite substrate is low.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a composite substrate, on which a heat-generating semiconductor device is to be mounted, and which has excellent heat dissipation properties with rare occurrence of cracking and peeling due to thermal stress.
Another object of the present invention is to provide a semiconductor apparatus comprising the composite substrate, on which a heatgenerating semiconductor device is mounted, and which has good heat dissipation properties with rare occurrence of crackings and peeling due to thermal stress.
According to the present invention, there is provided a composite substrate adapted to have a heat-generating semiconductor device mounted thereon, which comprises:
a composite layer containing a matrix of a high-thermal-conductivity metal and a fibrous or particulate dispersion material formed of a ceramic contained in said matrix; and
a solid metal layer having high heat dissipation properties and a high thermal conductivity provided onto a first main surface of said composite layer;
wherein either a heat-generating semiconductor device or a low-thermal-expansion substrate provided with a heat-generating semiconductor device, may be mounted on a second main surface of said composite layer; and
wherein a metal film serving as either one of a brazing material and solder is formed on a bonding face of said composite layer to said metal layer, and said metal layer is at least partially bonded onto said first main surface through said metal film.
According to the present invention, there is provided a semiconductor apparatus comprising the aforementioned composite substrate on which either one of a heat-generating semiconductor device and a low-thermalexpansion substrate provided with the heat-generating semiconductor device, is mounted on the main surface of the composite layer not facing the metal layer.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate certain exemplary constructions which are the subject of claims in the parent case and presently preferred embodiments of the invention claimed herein, and together with the general description given above and the detailed description of the drawings given below, serve to explain the principles of the present invention.
FIG. 1 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a first exemplary construction.
FIG.2 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a second exemplary construction.
FIG. 3 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a third exemplary construction.
FIG. 4 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a fourth exemplary construction.
FIG. 5 is a cross-sectional view of an example of the bonding portion of the composite layer and the metal film of the composite substrate shown in FIG. 4.
FIG. 6 is a cross-sectional view of another example of the bonding portion of the composite layer and the metal film of the composite shown in FIG.
4.
FIG. 7 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a fifth exemplary construction.
FIG. 8 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to Embodiment 1 of the present invention.
FIG. 9 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to Embodiment 2 of the present invention.
FIG. 10 is an enlarged cross-sectional view of the joint of the composite layer and the metal film forming the composite substrate shown in FIG.
9.
FIG. 11 is a cross-sectional view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to Embodiment 3 of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The composite substrate, on which a heat-generating semiconductor device is to be mounted, of the present invention, comprises a composite layer and a metal layer formed on one main surface of the composite layer. The composite layer contains a matrix made of a metal having a high thermal conductivity and a fibrous or particulate dispersion material having a low thermal expansion property dispersed in the matrix.
Since the dispersion material having a low thermal expansion property is dispersed in the metal matrix in the composite layer constituting the composite substrate of the present invention, it is possible to approximate the thermal expansion coefficient of the composite substrate to that of the semiconductor device. Therefore, excessive stress will not be applied to the bonding portion of the composite substrate to a heat-generating semiconductor device (or to a substrate with poor thermal expansion properties, provided with a heat generating semiconductor device). As a result, the reliability of the semiconductor apparatus can be enhanced.
As the layers are bonded with solder or by welding, the bonding strength between the metal layer and the composite layer can be improved and cracking and peeling will rarely take place within the composite substrate, and excessive stress will not be applied to the bonding portion of the composite substrate to a heat-generating semiconductor device. Hence, the reliability of the semiconductor apparatus can be enhanced.
Because the composite layer is soldered to the metal layer, deformation such as warpage due to thermal stress may take place because the thermal expansion coefficients of both layers differ. In such a case, the composite layer and the metal layer are not necessarily arranged contiguously in the thickness direction. To explain more specifically, only the composite layer is present in the thickness direction in some portions, whereas the composite layer and the metal layer may be present contiguously in other portions. Hence, the metal layer may be present in a discrete form. In this way, it is possible to reduce the total bonded area between the composite layer and the metal layer. As an extreme case, a metal layer of a pin-form may be directly connected to the composite layer.
In the composite layer thus constructed, warpage does not occur when the metal layer is bonded to the composite layer. Furthermore, if projections and depressions are formed on the surface of the discrete form metal layer which are connected only by way of the composite layer, improvement of heat dissipation can be expected. Since warpage of the composite substrate due to heat history at bonding will be suppressed by such modifications, the bonding can be performed by braze-bonding using an Al-Si base brazing material (for example,
BA4343, BA4045), if necessary.
When either a heat-generating semiconductor device or a substrate with poor thermal expansion properties, provided with a heat-generating semiconductor device, is mounted with soldering on the composite layer of the composite substrate mentioned above, the composite layer will exhibits poorer soldering properties due to the presence of dispersion material, than a metal layer containing no dispersion material. In particular, the composite layer made of an
Al-base matrix containing a dispersion material is poor in soldering properties.
Hence, even though no cracking and peeling take place within the composite substrate, they may take place at the soldering portion between the composite layer and a heat-generating semiconductor device or the substrate (poor thermal expansion) having a heat-generating semiconductor device mounted thereon, due to the poor soldering properties.
To overcome the aforementioned problems, a metal film or a metal plate having good soldering properties may be provided onto the surface of the composite layer of the composite substrate on which a heat-generating semiconductor device is to be mounted.
The presence of the metal film or the metal plate makes it possible to improve the soldering properties of the composite layer to the heat-generating semiconductor device or to the substrate (poor thermal expansion) having the heatgenerating semiconductor device mounted thereon, and to lower the occurrence of cracking and peeling at the soldering portion between the substrate and the device.
Hereinbelow, Embodiments of the present invention will be explained with reference to the drawings. However, firstly, the construction of certain substrates which are the subject of claims in the parent case will be described to assist understanding of the present invention.
FIG. 1 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a first construction. In FIG.
1, reference numeral 1 denotes a composite substrate on which a heat-generating semiconductor device is to be mounted. Numeral 7 denotes a heat-generating semiconductor device. The composite substrate 1 comprises a composite layer 2 and a metal layer 3 laminated in a thickness direction. In other words, the composite layer 2 constitutes part of the composite substrate 1 in the thickness direction. The thickness of the composite layer 2 is preferably from 1 - 20 mm.
The thickness of the metal layer 3 is preferably selected according to the output of the semiconductor device 7 mounted on the composite substrate 1.
The composite layer 2 is composed of a metal matrix 5 with high thermal conductivity and a dispersion material 4 with poor thermal-expansion properties dispersed in the matrix. The size of the fibrous dispersion material 4 preferably falls in the ranges of 0.1 - 100 ,um in diameter, and 20 llm or more in length. The volume filling ratio of the dispersion material 4 contained in the composite substrate is preferably in the range of 10 - 70%.
In this construction, the metal layer 3 is composed of the same metal as that used in the metal matrix 5 of the composite layer 2. The metal layer 3 is contiguous to the metal matrix 5 of the composite layer 2 with no material interposed therebetween.
The heat-generating semiconductor device 7 is bonded to the composite layer 2 with solder 6. Heat generated from the semiconductor device 7 is dissipated by passing through the composite layer 2 and the metal layer 3. In the composite layer, the vacant spaces between particles or fibers of the dispersion material 4 are filled with the metal matrix 5 having an excellent thermal conductivity to form a continuous sponge-form. Therefore, the composite layer 2 has an excellent thermal conductivity. The metal layer 3 is formed contiguously to the metal matrix 5 of the composite layer 2. Therefore, the thermal conductivity between them is excellent. The thermal conductivity within the metal layer 3 is also satisfactory.
Since the composite layer 2 contains the dispersion material 4 having poor thermal expansion properties, the composite layer 2 has considerably poor thermal expansion properties than the layer made of metal alone. Therefore, the thermal expansion properties of the composite layer 1 can be approximated to that of the semiconductor device 7. Hence, even if the temperature of the semiconductor device 7 changes, excessive stress may not be applied to the bonding portion of the semiconductor device 7 and the composite layer 2.
Then, to increase heat dissipation, it is desired to provide projections and depressions to the surface (outer surface) of the metal layer 3, as shown in the figure. Alternatively, the surface of the metal layer 3 may be formed flat.
As the material constituting the metal layer 3 and the metal matrix 5 of the composite layer 2, copper, copper alloys, aluminum, or aluminum alloys may be appropriately used.
As the dispersion material 4 constituting the composite layer 2, ceramic materials are used. Examples of the ceramic materials include Awl203, mullite, AIN, SiC, 2iO2, ZrO2 Si3N4, TiB2, ZrB2, 9Al203 B2O3, K2Ti6OtS, C and the like.
These dispersion materials may be used in the form of fibers or particles (powders). The dispersion materials may be appropriately chosen depending on required specification, i.e., cost, thermal expansion coefficient, thermal conductivity, and electric properties. Depending on required characteristics, the dispersion materials may be used alone or in combination of two or more materials. The thermal conductivity and thermal expansion coefficient of the composite layer may be controlled by varying the volume filling ratio of the dispersion material contained in the composite layer.
Although it is not shown in the figure, an insulating layer may be provided on the composite substrate, more specifically, on that surface of the composite substrate on which a heat-generating semiconductor device is to be mounted. If the semiconductor device is required to be electrically isolated from the substrate, an insulating layer must be provided onto the composite substrate since the composite layer of the composite substrate is conductive. If the insulating layer is provided, a circuit pattern can be formed on the surface thereof As a material for the insulating layer, glass epoxy may be used. When the metal matrix 5 is made of Al or Al alloy, alumite film may be used as the insulating layer.
The filling ratio of the dispersion material contained in the composite layer is preferably highest at the surface thereof and gradually decreases toward the inside. In this manner, the thermal expansion coefficient near the surface of the composite layer can be easily approximated to that of the semiconductor device and the thermal conductivity within the composite substrate can be further increased.
When the fiber-form dispersion material is used, it is preferable that the dispersion material is oriented in the direction of suppressing the thermal expansion. The thermal expansion of the composite layer can be efficiently decreased by this arrangement.
FIG. 2 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a second construction. In the construction shown in FIG. l, the composite layer 2 is present on the entire region of one surface of the composite substrate. Whereas in the construction shown in
FIG. 2, the composite layer 2 is present in the form of an island in the portion on which the heat-generating semiconductor device 7 is mounted. Alternatively, the composite layer 2 may be present in the form of a band extending through the area on which the semiconductor device 7 is mounted. The island-form or band-form composite layer 2 reduces the amount of the dispersion material used while maintaining good heat dissipation properties.
In FIG. 2, the same reference numerals are used to designate the same structural members corresponding to those shown in FIG. 1. Any further explanation is omitted since the structural members and materials used therein and modifications thereof excluding those mentioned above, are the same as those in
FIG. 1.
FIG. 3 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a third construction. In the construction shown in FIG. 1, the heat-generating semiconductor device 7 is directly soldered onto the composite layer 2. Whereas, in the construction shown in FIG. 3, a substrate 8 having the heat-generating semiconductor device 7 mounted thereon, is bonded with a solder 6 onto the composite layer 2. The substrate 8 used herein has poor thermal expansion properties. As the substrate 8, for example, DBC (direct bonding copper) substrate is used, which is an alumina plate having copper layers provided on both sides.
In FIG. 3, the same reference numerals are used to designate the same structural members corresponding to those shown in FIG. 1. Any further explanation is omitted since other structural members and materials used herein and modifications thereof excluding those mentioned above, are the same as those in FIG. 1. As the composite substrate 1, the substrate formed as shown in FIG. 2 may be employed herein.
FIG. 4 is a schematic view of a composite substrate on which a heat generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a fourth construction. In this construction, a metal film 9 having good soldering properties is provided over the surface of the composite layer 2. On the metal film 9, a substrate 8 (with poor thermal expansion properties) having the heat-generating semiconductor device 7 mounted thereon, is bonded with a solder 6. As the material for the metal film 9, Cu, Ni, Pd, Sn, Au, Ag, or the like may be used.
The composite layer 2 is inferior in soldering properties since it contains the dispersion material 4. However, if the metal film 9 is provided on the surface of the composite layer 2, the soldering properties of the composite layer 2 can be improved. In addition, the metal film 9 contributes to preventing the cracking and peeling due to thermal stress at the soldering portion. In the case where the metal matrix 5 of the composite layer 2 is made of aluminum or an aluminum alloy, it is particularly preferable to employ the structure shown in FIG.
4. The metal film 9 may be a single layer or a laminate structure consisting of at least two layers made of the aforementioned materials depending on requirements.
The metal film 9 may be formed by means of plating or the like. To improve the adhesion of the composite layer 2 to the metal film 9, it is better to provide projections and depressions to the surface of the composite layer 2, as shown in FIG. 5, followed by providing the metal film 9 thereon.
To improve the adhesion of the composite layer 2 to the metal film 9, the following method may be effective. In this method, some portions of the dispersion material 4 are allowed to protrude from the surface of the composite layer 2, as shown in FIG. 6, followed by forming the metal film 9 thereon. Since the protruding portions of the dispersion material 4 eat into the metal film 9, the adhesion is ensured. Such a structure can be obtained by etching the surface of the metal matrix 5 of the composite layer 2 to a depth of 5 to 50 pm and then forming the metal film 9 having good soldering properties over the etched surface in a thickness larger than the etching depth. The structure shown in FIG. 6 can be obtained by dispersing a fibrous-form dispersion material 4 in such a manner that at least 50 % of the dispersion material 4 is oriented in the direction with an angle (0) of 30 - 90C to the surface of the metal film 9.
In FIG. 4, the same reference numerals are used to designate the same structural members corresponding to those shown in FIG. 1. Any further explanation is omitted since the structural members and materials used herein and modifications thereof excluding those mentioned above are the same as those of
FIG. 1. The composite substrate 1 as shown in FIG. 2 may be employed herein.
The heat-generating semiconductor device 7 used herein may be soldered directly onto the surface of the metal film 9.
FIG. 7 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to a fifth construction. In this construction, a metal film 9 having good soldering property is provided in the form of an island or a band at the surface region of the composite layer 2 on which the substrate 8 having the heat-generating semiconductor device 7 mounted thereon, is to be soldered.
In FIG. 7, the same reference numerals are used to designate the same structural members corresponding to those shown in FIGS. 4-6. Any further explanation is omitted since the structural members and materials used herein and modifications excluding those mentioned above are the same as those in FIGS. 46.
Embodiment 1
FIG. 8 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to the first embodiment of the present invention. In this embodiment, the substrate 1 on which the heatgenerating semiconductor device is to be mounted, is constituted by a composite layer 2 and a metal layer 3, which are bonded to each other with a solder layer 10 interposed therebetween. With this structure, the thermal conductivity of the composite substrate 1 in the thickness direction decreases, compared to the case where the composite layer 2, the metal matrix 5, and the metal layer 3 constitute a continuous phase. However, if the thickness of the solder layer 10 is reduced to, for example, about 0.1 to 0.4 mm, sufficient heat dissipating properties can be obtained.
In the composite substrate of this embodiment, the metal layer 3 is made of the same metal or a metal of the same series as that used in the metal matrix 5 of the composite layer 2 in order to ensure the bonding by means of the solder layer 10 and to prevent the cracking and peeling at the bonding face due to thermal stress. For example, in the case where the metal matrix 5 of the composite layer 2 is made of Al or an Al alloy, the metal layer 3 should be made of Al or an
Al alloy. To bond the composite layer 2 to the metal layer 3, an Sn-Zn solder usually employed in aluminum bonding, is used.
In this embodiment, the metal film 9 having good soldering properties is formed on the surface of the composite layer 2. The substrate 8 with the heat-generating semiconductor device 7 mounted thereon is bonded to the metal film 9 with solder 6. In this respect, any further explanation is omitted since the construction is the same as that shown in FIGS. 4 to 6. The metal film 9 may be provided partially as is shown in FIG. 7. Furthermore, the heat-generating semiconductor device 7 may be directly solder-bonded either to the metal film 9 or to the composite layer 2 without providing the metal film 9. Any further explanation is omitted since the structure and materials used therein and modifications except those mentioned above are the same as those in FIG. 1.
Embodiment 2
FIG. 9 is a schematic view of a composite substrate on which a heatgenerating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate, according to the second embodiment of present invention. In this embodiment, a composite substrate 1 on which a heatgenerating semiconductor device is to be mounted, is formed of a composite layer 2 and a metal layer 3. The entire composite layer 2 is not in contact with the metal layer 3. To be more specific, the discrete metal layers 3a are partially formed on the rear surface of the composite layer 2.
Accordingly, in some portions of the composite substrate, only the composite layer 2 is present in the thickness direction. In other portions, both composite layer 2 and the isolated metal layers 3a are present in a continuous form in the thickness direction. With the structure mentioned above, the area of the bonding surface of the composite layer 2 in contact with the metal layer 3a can be reduced.
This structure is also effective to reduce the thermal stress ascribed to the difference in thermal expansion rate between the metal layers 3a and the composite layer 2 when the metal layers 3a are bonded to the composite layer 2.
Consequently, distortion of the composite substrate 1 due to warpage can be prevented.
Since the thermal stress between the composite layer 2 and the metal layers 3a is suppressed, the composite layer 2 can be bonded to the metal layers 3a with solder 13, as shown in the enlarged view of FIG. 10. Alternatively, the bonding may be made at relatively high temperatures by use of e.g. an Al-Si base blazing material (such as BA4343, A4045). In this case, a solder having a higher melting point can be used when other structural members are attached. Therefore, fabrication of the semiconductor apparatus can be carried out with high degree of freedom.
Alternatively, if solder or a brazing material is applied to the surface of the composite layer 2 to be bonded to the metal layers 3a, and discrete metal layers 3a are fixed all together to the composite layer 2 by use of a tool, and bonded thereto, the mass production of the composite substrate can be attained.
To facilitate the bonding in this embodiment, a metal film (not shown in FIG. 9) may be formed on the surface of the composite layer 2.
Embodiment 3
FIG. 11 is a schematic view of a composite substrate on which a heat-generating semiconductor device is to be mounted, and a semiconductor apparatus provided with the composite substrate. In this embodiment, discrete metal layers 3b are further bonded to the surface of each of the metal layers 3a shown in Embodiment 2. In this manner, projection and depressions are provided.
With the structure having the metal layers 3a and 3b, the surface area of the metal layer increases. Consequently, the heat dissipation is improved.
Incidentally, the metal layers 3b are bonded to the metal layers 3a with solder 13 in the Embodiment of FIG. 11. However, the metal layers 3b may be formed by machining the metal layers 3a.
Also in this embodiment, a metal film (not shown in FIG. 11) may be formed on the surface of the composite layer 2 to facilitate the bonding.
Any further explanation is omitted since the structure and materials used therein and modifications thereof are the same as those in FIG. 1.
Hereinbelow, Examples of the present invention will be specifically described on the Embodiments mentioned above.
Example 1
In this Example, there will be explained a composite substrate on which a heat-generating semiconductor device is to be mounted and a method of manufacturing a semiconductor apparatus employing the composite substrate, with reference to FIG. 8.
As the dispersion materials, used were a SiC fiber (average diameter: 0.3 corm, average length: 90 corm), a 9A1203 2q 2B203 fiber (average diameter: 0.5 ym, average length: 30 Rm), and an A1N fiber (average diameter: 1 ,um, average length: 30 Cun). Then, porous fiber molded products having a volume filling ratio (Vf) of 40% were prepared for each of the aforementioned fibers. The dimensions of the porous molded products were 100 mm x 100 mm x 5 mm. Each of the porous molded products was set in a cavity (having the same shape as the molded products) of a pressure casting machine. Pressure-casting was made by using an Al-Si7% matrix melt. In this manner, composite boards were prepared comprising a metal matrix in which a fiber with poor thermal expansion properties was dispersed.
Each of the composite boards 2 thus formed was subjected to pretreatment with an alkaline solution (sodium hydroxide) for 70 seconds at 50"C.
In the pretreatment, the surface of the composite board was modified by removing oil components therefrom. Thereafter, a Zn underlying layer (1 to 2 um thick) was formed on the resultant board by zincate treatment. On the surface of the Zn underlying layer, Ni was plated at normal temperature and with a current density of 4A/cm2, thereby forming a Ni-plated layer 9 (metal film) of 10 ",lm thick on one surface of the composite board 2.
Further on the other surface of Ni-plated composite board, a metal plate (Al-Si 7 %) 3 serving as a heat sink was bonded with Si-Zn solder 10 (0.2 mm thick). In this manner, a composite substrate was formed. On the Ni-plated layer 9 of the composite substrate, a DBC substrate 8 (70 mm x 70 mm x 1.2 mm) having a heat-generating semiconductor device mounted thereon, was bonded with an eutectic solder 6. In this way, a semiconductor apparatus 1 was manufactured.
Example 2
In this Example, there will be explained a composite substrate on which a heat-generating semiconductor device is to be mounted and a method of manufacturing a semiconductor apparatus employing the composite substrate, with reference to FIG. 9.
As the dispersion materials, used were a SiC fiber (average diameter: 0.3 Wn, average length: 90 clam) and a C fiber (average diameter: 10 clam, average length: 200 cut). Then, porous molded products having a volume filling ratio (Vf) of 40% were prepared for each of the aforementioned fibers. The dimensions of the porous molded products were 100 mm x 100 mm x 5 mm. Each of the porous molded products was set in a cavity (having the same shape as the molded products) of a pressure casting machine. Pressure-casting was made by using A1- Si22 wtO/o matrix melt. In this manner, the composite board 2 was prepared comprising a metal matrix in which a fiber with poor thermal expansion properties was dispersed.
To one surface of the composite board 2 thus manufactured, Ni was plated in the same manner as in Example 1, thereby forming a Ni plated layer (metal film) of 10 Rm thick. Onto the other surface of the composite board 2, 100 cylindrical pieces 3a (which correspond to a metal layer) made of Al having 5 mm in diameter and 25 mm in length were bonded almost uniformly. The composite board 2 was bonded to the cylindrical pieces 3a as follows:
A thin plate coated with a flux made of brazing material (BA4045) of 7 mm diameter was set at a predetermined surface position of the composite board 2 at which a metal layer is to be connected. Thereafter, cylindrical members 3a were aligned on the thin plate, and then, about 2 kg weight was mounted on the cylindrical members 3a.
Then, the resultant structure was allowed to stand in a furnace maintained at 5950C for 10 minutes, thereby forming a metal layer 3a consisting of cylindrical members. Through the steps mentioned above, the composite substrate was manufactured. Thereafter, a DBC substrate 8 having a heatgenerating semiconductor device mounted thereon, was bonded onto the composite substrate with an eutectic solder. In this manner, a semiconductor apparatus was manufactured.
As explained in the foregoing, according to the present invention, there is provided a composite substrate on which a heat-generating semiconductor device is to be mounted and a semiconductor apparatus, the composite substrate having good heat dissipation properties with rare occurrence of cracking and peeling at the interface between the composite substrate and the heat-generating semiconductor device, or between the composite substrate and a substrate (with poor thermal expansion properties) having a heat-generating semiconductor device mounted thereon. Therefore, the development of large-scale semiconductor devices and operation of the semiconductor device with high power can be realized by the present invention.
Claims (18)
1. A composite substrate adapted to have a heat-generating semiconductor device mounted thereon, which comprises:
a composite layer containing a matrix of a high-thermal-conductivity metal and a fibrous or particulate dispersion material formed of a ceramic contained in said matrix; and
a solid metal layer having high heat dissipation properties and a high thermal conductivity provided onto a first main surface of said composite layer;
wherein either a heat-generating semiconductor device or a low-thermal-expansion substrate provided with a heat-generating semiconductor device, may be mounted on a second main surface of said composite layer; and
wherein a metal film serving as either one of a brazing material and solder is formed on a bonding face of said composite layer to said metal layer, and said metal layer is at least partially bonded onto said first main surface through said metal film.
2. The composite substrate according to claim 1, wherein a metal film having good soldering properties is provided onto said first main surface of said composite layer.
3. The composite substrate according to claim 2, wherein projections and depressions are provided to said first main surface of said composite layer in order to improve adhesion to said metal film.
4. The composite substrate according to claim 2, wherein portions of said dispersion material protrude from said first main surface of said composite layer and said protruding portions intrude into said metal film.
5. The composite substrate according to claim 1, wherein a metal plate having good soldering properties is bonded to said first main surface of said composite layer.
6. The composite substrate according to claim 5, wherein said composite layer is bonded to said metal layer by laminating a porous molded product constituting said dispersion material with a metal plate, supplying a metal constituting said matrix, and then casting with pressure.
7. The composite substrate according to claim 6, wherein projections and depressions are provided to a surface of said metal plate to be bonded to said composite layer, in order to improve a bonding strength to said composite layer.
8. The composite substrate according to claim 6, wherein a metal is plated onto a surface of said metal plate bonded to said composite layer, in order to improve a bonding strength to said composite layer.
9. The composite substrate according to claim 1, wherein said matrix and said metal layer are made of aluminum or an aluminum alloy.
10. The composite substrate according to claim 1, wherein said matrix and said metal layer are made of copper or a copper alloy.
11. The composite substrate according to claim 1, wherein said composite layer is present in the form of an island or a band on one surface of said metal layer.
12. The composite substrate according to claim 1, wherein projections and depressions are provided to a surface of said metal layer not facing said composite layer, in order to improve heat dissipation properties.
13. The composite substrate according to claim 1, wherein a volume filling ratio of a dispersion material contained in said composite layer is highest at a surface of said composite layer and decreases toward the inside thereof.
14. The composite substrate according to claim 1, wherein said composite layer contains a fibrous dispersion material which is oriented in the direction of suppressing thermal expansion of said composite layer.
15. The composite substrate according to claim 1, wherein an insulating layer is provided onto said second main surface of said composite layer.
16. A semiconductor apparatus comprising a composite substrate according to any preceding claim and either a heat-generating semiconductor device or a low-thermal-expansion substrate provided with a heat-generating semiconductor device mounted on said second main surface of the composite layer of said composite substrate.
17. A composite substrate for heat-generating semiconductor device substantially as hereinbefore described with reference to the accompanying drawings.
18. A semiconductor apparatus using a composite substrate for a heatgenerating semiconductor device substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6418796 | 1996-03-21 | ||
| JP25062996 | 1996-09-20 | ||
| GB9705237A GB2311414B (en) | 1996-03-21 | 1997-03-13 | Composite substrate for heat-generating semiconductor device and semiconductor apparatus using the same |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9823805D0 GB9823805D0 (en) | 1998-12-23 |
| GB2327150A true GB2327150A (en) | 1999-01-13 |
| GB2327150B GB2327150B (en) | 1999-07-07 |
Family
ID=27268773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9823805A Expired - Fee Related GB2327150B (en) | 1996-03-21 | 1997-03-13 | Composite substrate for heat-generating semiconductor device and semiconductor decice and semiconductor apparatus using the same |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2327150B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1695382A1 (en) * | 2001-05-24 | 2006-08-30 | Fry's Metals Inc. | Thermal interface material and solder preforms |
| US7663242B2 (en) | 2001-05-24 | 2010-02-16 | Lewis Brian G | Thermal interface material and solder preforms |
| US7709951B2 (en) * | 2007-03-16 | 2010-05-04 | International Business Machines Corporation | Thermal pillow |
| WO2019110219A1 (en) * | 2017-12-04 | 2019-06-13 | Siemens Aktiengesellschaft | Heat sink for an electronic component, electronic subassembly with a heat sink of this kind and method for producing a heat sink of this kind |
| CN111647766A (en) * | 2020-06-11 | 2020-09-11 | 昆明理工大学 | Preparation method of copper-based composite material |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0471552A1 (en) * | 1990-08-14 | 1992-02-19 | Texas Instruments Incorporated | Heat transfer module for ultra high density and silicon on silicon packaging applications |
-
1997
- 1997-03-13 GB GB9823805A patent/GB2327150B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0471552A1 (en) * | 1990-08-14 | 1992-02-19 | Texas Instruments Incorporated | Heat transfer module for ultra high density and silicon on silicon packaging applications |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1695382A1 (en) * | 2001-05-24 | 2006-08-30 | Fry's Metals Inc. | Thermal interface material and solder preforms |
| EP1695382A4 (en) * | 2001-05-24 | 2007-10-10 | Fry Metals Inc | Thermal interface material and solder preforms |
| US7663242B2 (en) | 2001-05-24 | 2010-02-16 | Lewis Brian G | Thermal interface material and solder preforms |
| US7709951B2 (en) * | 2007-03-16 | 2010-05-04 | International Business Machines Corporation | Thermal pillow |
| WO2019110219A1 (en) * | 2017-12-04 | 2019-06-13 | Siemens Aktiengesellschaft | Heat sink for an electronic component, electronic subassembly with a heat sink of this kind and method for producing a heat sink of this kind |
| US11948856B2 (en) | 2017-12-04 | 2024-04-02 | Siemens Aktiengesellschaft | Heat sink for an electronic component |
| CN111647766A (en) * | 2020-06-11 | 2020-09-11 | 昆明理工大学 | Preparation method of copper-based composite material |
| CN111647766B (en) * | 2020-06-11 | 2021-05-11 | 昆明理工大学 | A kind of preparation method of copper matrix composite material |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9823805D0 (en) | 1998-12-23 |
| GB2327150B (en) | 1999-07-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20030313 |