Multi-layer compound passivation layer structure of Bipolar circuit and manufacturing process thereof

Abstract

The invention provides a multi-layer compound passivation film structure of a Bipolar circuit, which comprises a bottom silicon oxide film layer and a silicon nitride film layer, wherein the silicon oxide film layer is deposited on the surface of a silicon substrate, and the silicon nitride film layer is deposited on the silicon oxide film layer; a certain proportion of phosphine is doped in the silicon oxide film layer; and the silicon oxide film layer sequentially comprises an undoped silicon oxide layer, a doped phosphorosilicate glass layer and an undoped silicon oxide layer. Meanwhile, the invention also provides a manufacturing process of the multi-layer compound passivation film of the Bipolar circuit. The multi-layer compound passivation film structure of the Bipolar circuit has scratch resistance, moisture resistance, high density, low film stress, higher impurity absorbing ability, better step covering ability and excellent photoelectric properties, electrical characteristics and heat stability, reduces the soft breakdown, and solves the problems of poor reliability, and the like.

Description

technical field [0001] The invention relates to a passivation layer structure and a passivation layer generation process in the field of semiconductor manufacturing, in particular to a multilayer composite passivation layer structure of a Bipolar circuit and a generation process method thereof. Background technique [0002] Silicon oxide is widely used as a conventional passivation film structure in Bipolar circuits due to its relatively small stress on the silicon substrate and aluminum film. However, due to the shortcomings of silicon oxide such as radiation sensitivity, low scratch resistance, poor photoelectric performance, weak moisture resistance and mobile ion penetration, it is limited in special semiconductor processes and devices (such as silicon photoelectric application in conversion circuits, etc.). For the silicon oxide film formed by the conventional low-pressure chemical vapor deposition method, due to its better step conformality, in the double-layer wiring...

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Problems solved by technology

However, due to the shortcomings of silicon oxide such as radiation sensitivity, low scratch resistance, poor photoelectric performance, weak moisture resistance and mobile ion penetration, it is limited in special semiconductor processes and devices (such as silicon photoelectric conversion circuits, etc.)

For the silicon oxide film formed by the conventional low-pressure chemical vapor deposition method, due to its better step conformality, in the double-layer wiring process without planarization process, the passivation film is between the vertical edge and the surface parallel to the layer. Gaps are prone to appear at the corners of high steps, which weakens the protective effect of the silicon oxide passivation film here, thereby affecting the thermal stability and reliability of the circuit

Silicon nitride is another commonly used passivation layer dielectric material. Its barrier effect on mobile ions and water vapor is the best among all commonly used dielectric materials, and it has high scratch resistance. However, silicon nitride material The step coverage ability of the aluminum alloy is poor, and it is prone to breakage at high steps without a planarization process. At the same time, its expansion coefficient is greatly different from that of aluminum materials, and it is easy to deform after high temperature annealing

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