JPH0569312B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and more particularly to a bipolar integrated circuit having a resistive element using a barrier metal film used in an electrode part to prevent aluminum alloy spikes. It is something.

[Conventional technology]

Conventionally, resistance elements that have been installed in bipolar integrated circuits include resistance elements that use an epitaxial single crystal film (called a diffused resistance), and resistance elements that use a polycrystalline silicon film deposited on an insulating film such as an oxide film. There are elements (polycrystalline silicon resistors), etc.

[Problem that the invention seeks to solve]

In the case of the conventional diffused resistor described above, a p-type conductive region is usually provided within an n-type conductive region to form a resistance element, so (1) the n-type conductive region is separated into other regions with a pn junction or an insulating film. There is a need to. (2) It is necessary to maintain the n-type conductive region at the highest potential. (3) There is a delay in operating speed due to pn junction capacitance. These drawbacks have limited improvements in integrated circuit performance and integration density, and have placed significant restrictions on pattern layout.

On the other hand, in the case of polycrystalline silicon resistors, the disadvantages of (1), (2), and (3) above are eliminated because they can be formed on an insulating film, but a significant disadvantage is that they have a temperature coefficient of resistance. ing. As the layer resistance increases, the temperature coefficient rapidly increases, and when using various resistances in a circuit, it is necessary to take an operating margin against temperature changes or provide a temperature compensation circuit. This is a factor that significantly reduces the degree of freedom in design.

Also, when attaching electrode wiring to a resistance element,
Conventionally, Al wiring was connected after opening a contact hole in an insulating film such as an oxide film or nitride film on a resistor element, but in this structure, aluminum alloy spikes are used for heat treatment in the wafer manufacturing process and assembly process. This may cause an increase in contact resistance and a fluctuation in resistance value. This variation in resistance value is directly linked to variation in characteristics, posing a problem from the quality perspective of ICs and LSIs.

The present invention eliminates the above-mentioned conventional drawbacks, has a structure that prevents aluminum alloy spikes, has an extremely small temperature coefficient on an insulating film, and realizes a resistive element without parasitic capacitance such as a pn junction. It is an object of the present invention to provide a semiconductor device in which the resistance can be changed significantly and the degree of freedom in circuit design and pattern layout can be greatly increased.

[Means for solving problems]

In the semiconductor device of the present invention, an electrode contact opening provided in an insulating film on a semiconductor substrate and an electrode wiring metal formed to cover the electrode contact opening are prevented from entering the contact surface. and a resistive element formed by introducing atoms different from the main constituent atoms of the barrier film into the same metal film as the barrier film, which is provided on an insulating film in succession to the barrier film. be done.

Further, by ion-implanting oxygen atoms into the resistive element region of the barrier film and then performing heat treatment, the layer resistance can be significantly changed, and a resistive element having a predetermined resistance value can be easily obtained.

〔Example〕

Next, the present invention will be explained with reference to the drawings. 1 to 3 are schematic diagrams of main steps for explaining an embodiment of the present invention and its manufacturing method, in which FIG. 1 is a sectional view, and FIGS. 2 and 3 are plan views. In this embodiment, a collector load resistance in an emitter-coupled logic circuit will be explained as an example.

First, a manufacturing method of one embodiment will be explained using FIGS. 1 to 3. In FIG. 1, a collector contact opening 4 is provided in an oxide film 2 covering the surface of a silicon substrate 1. As shown in FIG. Next, a titanium nitride (TiN) film 5 is sputtered to a thickness of 0.2 μm over the entire surface as a barrier film. Note that 3 is a collector diffusion layer that has already been formed.

Next, as shown in FIG. 2, a resist film is first formed on the TiN film 5 using a normal photolithography technique, and the resist film is used as a mask.
A predetermined resistance element shape 6 is obtained by etching and removing unnecessary TiN film in H ₂ O ₂ solution.

Next, as shown in FIG. 3, an aluminum film 7 with a thickness of about 1 μm is formed so as to cover only the collector contact 4 portion, oxygen atoms are ion-implanted over the entire surface, and then heat treatment is performed at 400 to 500°C. Next, by removing the aluminum film 7, the resistor element 8 is completed and the semiconductor device of this embodiment is obtained.

The layer resistance of the resistive element obtained in this way is
Varies depending on the amount of oxygen atoms implanted, 10 ¹⁶ to 10 ¹⁸ cm
With an implantation dose of ⁻² , a layer resistance of several hundred Ω/□ to several tens of KΩ/□ is achieved. Further, the reason why oxygen atoms are not implanted into the electrode portion is to prevent contact resistance from increasing.

In addition, the temperature coefficient of the resulting resistance element is extremely small compared to diffused resistance or polycrystalline silicon resistance.
It is about several tens of ppm/℃.

[Effect of the invention] As explained above, if the present invention is used, it has a structure that prevents aluminum alloy spikes,
A resistor element with an extremely small temperature coefficient and no parasitic capacitance such as a pn junction can be realized on an insulating film, and the layer resistance can be changed significantly, greatly increasing the degree of freedom in circuit design and pattern layout. You can get the effect that you can.

[Brief explanation of the drawing]

1 to 3 are schematic diagrams of main steps for explaining an embodiment of the present invention and its manufacturing method, in which FIG. 1 is a sectional view, and FIGS. 2 and 3 are plan views. DESCRIPTION OF SYMBOLS 1... Silicon substrate, 2... Oxide film, 3... Contact diffusion layer, 4... Opening part for collector contact, 5... Titanium nitride film, 7... Aluminum film, 8... Resistance element.

Claims (1)

[Scope of Claims] 1. An electrode contact opening provided in an insulating film on a semiconductor substrate, and a method for preventing an electrode wiring metal formed covering the electrode contact opening from entering the contact surface. It is characterized by comprising a barrier film, and a resistance element formed by introducing atoms different from the main constituent atoms of the barrier film into the same metal film as the barrier film, which is provided on an insulating film in succession to the barrier film. semiconductor devices. 2. The semiconductor device according to claim 1, wherein the barrier film is made of titanium nitride, and the atoms different from the main constituent atoms of the barrier film are oxygen atoms.