Patent Application
20070284731
In the following, embodiments of the power module according to the invention will be described, together with its heat-dissipating structure, with reference to the drawings.
The heat generated by the IGBT chip is conducted by the individual layers before it is dissipated via the heat sink into water or to the air.
It is noted that instead of the conventional metal heat dissipating plate made of Cu—Mo or the like, which is relatively expensive, the present invention also advantageously allows the use of a metal heat dissipating plate made of Cu, which is inexpensive and of which there is not much price fluctuations.
As in Embodiment 1, the heat generated by the IGBT chip is conducted by the individual layers before it is dissipated via the heat sink into water or to the air.
As in Embodiment 1, the heat generated by the IGBT chip is conducted by the individual layers and before it is dissipated via the heat sink into water or to the air.
As in Embodiment 1, the heat generated by the IGBT chip is conducted by the individual layers before it is dissipated via the heat sink into water or to the air.
The problems of prior art that are solved by the invention include the following. First, with regard to the issue of bonding between the individual layers, the present invention does not require soldering for the bonding with the lower heat dissipating plate or the like. Therefore, no metal plate is required at the bottom of the insulating material. Furthermore, the type of metal that can be bonded to the resin insulating material, such as polyimide, is not limited to aluminum but may be Cu or other general-purpose metal. In this respect, the invention offers another advantage that metals having high wettability, such as Cu, do not require Ni plating.
Next, with regard to the issue of thermal expansion in the individual layers, a thin film of thermoplastic polyimide material has a very low Young's modulus such that it does not break when subjected to bending stress but instead absorbs the bending stress, thus preventing the device from being affected by such stress. Thus, the invention offers the advantage that the heat dissipating plate can be made of a general-purpose metal that has high thermal expansion and is inexpensive, such as copper or aluminum.
In the following, thermoplastic polyimide suitable as a resin-based insulating material for the invention will be described.
In accordance with the present invention, the thermoplastic polyimide is preferably an aromatic polyimide. Aromatic polyimides are a condensation product of an aromatic tetracarboxylic acid with an aliphatic or aromatic diamine. They are typically obtained by producing an amide acid by the condensation polymerization of tetracarboxylic acid dianhydride, such as pyromellitic acid dianhydride or biphenyltetracarboxylic acid dianhydride, and diamine, such as paraphenylene diamine or diaminodiphenyl ether, followed by ring-closing curing by heat or a catalyst. Such thermoplastic polyimide can be obtained by copolymerization of the following compounds, for example.
Examples of dicarboxylic anhydride include: pyromellitic acid dianhydride; 4,4′-oxydiphthalic acid dianhydride; 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride; 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride; 2,2′,3,3′biphenyltetracarboxylic acid dianhydride; 2,2′-bis(3,4-dicarboxyphenyl)hexafuluoropropane dianhydride; bis(3,4-dicarboxyphenyl)sulfone dianhydride; bis(3,4-dicarboxyphenyl)sulfide dianhydride; bis(2,3-dicarboxyphenyl)methane dianhydride; bis(3,4-dicarboxyphenyl)methane dianhydride; 1,1-bis(2,3-dicarboxyphenyl)methane dianhydride; 1,1-bis(2,3-dicarboxyphenyl)propane dianhydride; 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride; and m-phenylenebis(trimellitic acid)dianhydride; 2,2′-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.
Examples of diamine include: hexamethylenediamine; heptamethylenediamine; 3,3′-dimethylpentamethylenediamine; 3-methylhexamethylenediamine; 3-methylheptamethylenediamine; 2,5-dimethylhexamethylenediamine; octamethylenediamine; nonamethylenediamine; 1,1,6,6-tetramethylhexamethylenediamine; 2,2,5,5-tetramethylhexamethylenediamine; 4,4-dimethylheptamethylenediamine; decamethylenediamine; m-phenylenediamine; 4,4′-diaminobenzophenone; 4-aminophenyl-3-aminobenzoate; m-aminobenzoil-p-aminoanilide; 4,4′-diaminodiphenyl ether; 3,4′-diaminodiphenyl ether; bis(4-aminophenyl)methane; 1,1-bis(4-aminophenyl)ethane; 2,2-bis(4-aminophenyl)propane; 2,2′-bis[4-(4-aminophenoxy)phenyl)]propane; 4,4′-diaminodiphenyl sulfoxide; 3,3′-diaminobenzophenone; 1,3-bis(4-aminophenoxy)benzene; 2,2′-diaminobenzophenone; 1,2-bis(4-aminophenoxy)benzene; 1,3-bis(4-aminobenzoyloxy)benzene; 4,4′-dibenzanilide; 4,4′-bis(4-aminophenoxy)diphenylether; 2,2′-bis(4-aminophenyl)hexafluoropropane; 4,4′-diaminodiphenylsulfone; 1,12-diaminododecane; 1,16-diaminohexadecane; and polysiloxanediamine; 1,3-bis(3-aminobenzoyloxy)benzene; 1,4-bis(4-aminophenoxy)benzene; 4,4-bis(4-aminopheoxy)biphenyl; 4,4-bis(4-aminophenoxy)diphenylsulfone; 4,4-bis(3-aminophenoxy)diphenylsulfone; 2,2-bis(4-[4-aminophenoxy]phenyl)-1,1,1,3,3,3-hexafluoropropane; 3,3′-diaminophenylsulfone; and p-phenylenediamine.
Of the above compounds, particularly preferable as a thermoplastic polyimide used in the present invention are a copolymer of 1,3-bis(4-aminophenoxy)benzene (abbreviated as RODA), pyromellitic acid dianhydride (abbreviated as PMDA), and 4,4′-oxydiphthalic acid dianhydride (ODPA), a copolymer of 4,4′-diaminodiphenyl ether (abbreviated as ODA) and 3,3′4,4′-biphenyltetracarboxylic acid dianhydride (abbreviated as BPDA), a copolymer of ODA, PMDA, and BPDA, and a copolymer of 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BTDA), PMDA, and 2,2′-bis[4-(4-aminophenoxy)phenyl)]propane (abbreviated as BAPP).
In accordance with the invention, the glass transition temperature of the thermoplastic polyimide, which is softened when heated, is from 200° C. to 350° C. and more preferably from 210° C. to 300° C.
In accordance with the invention, by using a resin-based insulating material in the heat-dissipating structure of a power module instead of the conventional ceramic insulating material, the mounting structure of the power device can be simplified and a cost reduction can be achieved and, in addition, improvements in heat dissipation and the reliability of the module can be achieved. By equipping a hybrid automobile with the aforementioned inverter module, widespread use of hybrid vehicles can be promoted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-115823 | Apr 2006 | JP | national |
