JPH0115153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a hybrid integrated circuit that enables highly reliable wire bonding between a semiconductor and a circuit using aluminum lead wires only by etching without the need for complicated operations.

Conventionally, hybrid integrated circuits have generally been made by attaching circuit components such as resistors and transistors to a ceramic or glass substrate, or by providing an insulating layer on an aluminum or iron substrate and incorporating a circuit on top of this. .

On these boards, die bonding of semiconductors is done by soldering, terminal connections to the outside, and chip parts such as chip capacitors are attached, and connections between semiconductors and circuits are made by wire bonding with gold or aluminum wires. ing.

For connecting aluminum wires, use precious metal plating or nickel plating (special public
-3461), aluminum evaporation plating (Japanese Patent Application Laid-open No. 1973)
-28662) and adhesion of metal pellets (Special Publication No. 1973)
-37110), and various other proposals. However, in the case of plating, in addition to requiring plating equipment, it is also necessary to control the accuracy of the plating surface and the layer thickness. Furthermore, in the case of bonding metal pellets, the number of bonded pellets is greater than the number of semiconductor die bondings, and these operations are extremely complicated.

Furthermore, in a copper foil circuit having a polymer resin insulating layer, since the insulating layer has a low Young's modulus, when wire bonding is performed using ultrasonic vibration, there is a phenomenon in which so-called ultrasonic waves are lost, making it impossible to perform sufficient bonding. Furthermore, in the noble metal plating and nickel plating methods, precision of the bonding surface is strictly required, and the ultrasonic vibration bonding conditions must also be operated within a narrow range.

The present invention solves these drawbacks,
A wiring circuit is formed by etching the aluminum-copper clad foil, which is a laminate made by sequentially laminating an insulating layer and an aluminum-copper clad foil on a metal substrate, with iron chloride, etc., which can etch both aluminum and copper. In addition, the aluminum circuit and copper circuit are exposed by etching with alkali or ammonium persulfate, and then the copper circuit, semiconductor, and other components are laminated via solder, and the semiconductor and aluminum circuit are bonded using aluminum lead wires. It is an object of the present invention to provide a method for manufacturing a hybrid integrated circuit that is fixed by sound waves.

That is, the present invention provides the aluminum-copper cladding of a laminate which is formed by sequentially laminating and integrating an insulating layer and an aluminum (10 to 100μ)-copper cladding foil (hereinafter referred to as aluminum-copper cladding foil) on a metal substrate. The method is characterized in that the foil is etched to form a wiring circuit, further etched to form an aluminum circuit, and then the aluminum circuit and semiconductor are fixed by an aluminum lead wire using an ultrasonic vibration method.

Examples of the present invention will be explained in detail below with reference to the drawings.
4 are cross-sectional views of examples, and FIG. 5 is a diagram showing the relationship between ultrasonic output and tensile strength.

First, as shown in FIG. 1, in the laminate used in the present invention, an insulating layer 2 is laminated on a metal substrate 1, and aluminum 3 and copper 4 are stacked so that the aluminum foil 3 is placed on the surface of the insulating layer 2. The aluminum-copper clad foil 8 shown in FIG. The cladding foil 8 is laminated.

Next, this aluminum-copper clad foil 8 is etched with etchingable iron chloride or the like to form a wiring circuit. Next, the laminate shown in FIG. 2 is etched by the method described above, and as shown in FIG. 3, a part of the metal substrate 1, insulator layer 2, and aluminum circuit 3' is alkali-etched to form a copper circuit 4'. After exposing the copper circuit 4' and placing a semiconductor, a chip low antibody, etc. on the copper circuit 4' via the solder 7, the semiconductor 6 and the aluminum circuit 3' are fixed by an aluminum lead wire 5 using an ultrasonic vibration method. . Further, the laminate shown in FIG. 1 is etched by the above-described method, and further, as shown in FIG. 4, a part of the metal substrate 1, insulator layer 2, and copper circuit 4 is etched with ammonium persulfate, etc., and then wire bonded. exposing the aluminum circuit 3' that will become the
A semiconductor, a chip low antibody, etc. are placed on the copper circuit 4' via solder 7 as in FIG. 3, and the semiconductor 6 and the aluminum circuit 3' are connected by the aluminum lead wire 5 using the ultrasonic vibration method. .

The metal substrate 1 used in the present invention is made of aluminum, iron, etc. with a thickness of 0.5 to 3.0 mm and has good thermal conductivity, and the insulating layer 2 is made of various ceramics,
A polymer resin insulation layer containing inorganic powder, a polymer resin insulation layer containing glass fiber, and a heat-resistant polymer resin insulation layer are used, and the thickness thereof is 20 μm or more. The inorganic powder is preferably alumina, beryllia, boron nitride, magnesia, silica, etc., and the polymer resin is preferably epoxy resin, phenolic resin, polyimide resin, etc. Further, as the insulating layer 2, an insulating layer containing a polymeric resin is preferable, and furthermore, the aluminum of the aluminum-copper clad foil 8 has a thickness of 10 to 100μ, and if the aluminum is less than 10μ, thick aluminum lead wires cannot be fixed. Furthermore, the adhesive strength is weak, resulting in poor reliability. Moreover, there is no problem if the thickness exceeds 100μ, but it only increases the cost. Copper preferably has a thickness of 0.1 to 100μ. Furthermore, a foil made of aluminum plated with copper may be used. It is also possible to sequentially plate aluminum with different metals, such as nickel and copper.

Next, a 30μ aluminum wire was ultrasonic wire bonded using a metal substrate made by bonding a 2mm thick aluminum plate with a 50μ aluminum-copper clad foil or a 35μ gold or nickel plated copper foil with epoxy adhesive. Figure 5 shows the relationship between the type of bonding pad and the tensile strength. That is, by selectively etching the aluminum-copper clad foil according to the present invention,
It can be seen that in an experimental example in which a bonding pad of 15μ aluminum foil was formed, the tensile strength was higher than when gold plating or nickel plating was applied on a 35μ copper foil, and there was less variation in the tensile strength. This large variation in tensile strength when plated means that the properties of the plated surface have a significant effect on wire bonding properties.
This is an unavoidable drawback when forming a bonding pad by plating.

As explained above, the present invention sequentially laminates an insulating layer and an aluminum-copper cladding foil on a metal substrate,
The aluminum-copper cladding foil is etched to form a wiring pattern, and a bonding pad is also formed, so that the semiconductor, etc. and the aluminum circuit can be easily and firmly bonded to the aluminum lead wire using an ultrasonic vibration method. It is something.

[Brief explanation of drawings]

1 to 4 are cross-sectional views of embodiments of the present invention,
FIG. 5 shows examples and comparative examples of tensile strength. Symbol 1...Metal substrate, 2...Insulator layer, 3...Aluminum foil, 3'...Aluminum circuit, 4...Copper foil,
4'...Copper circuit, 5...Aluminum lead wire, 6...
Semiconductor, 7...Solder, 8...Aluminum-copper clad foil.

Claims (1)

[Claims] 1 Metal substrate with insulating layer, aluminum (10~
100μ) - The above-mentioned aluminum (10 to 100μ), which is a laminate made by laminating copper clad foils in sequence and integrating them.
- A copper clad foil is etched to form a wiring circuit, further etched to form an aluminum circuit or a copper circuit, and the aluminum circuit and semiconductor are fixed with an aluminum lead wire using an ultrasonic vibration method. A method for manufacturing hybrid integrated circuits.