Inductor applied to backside illuminated image sensor chip

Abstract

The invention provides an inductor applied to a back-illuminated image sensor chip. A main body circuit arranged on the front face of a substrate and a chip bonding pad arranged on the back face of the substrate are connected with each other, a bonding wire connecting the chip bonding pad with a packaging bonding pad is used as the inductor, the situation that a large area of the front face of the substrate is occupied is avoided, the chip integration degree is improved, coupling interference in the main body circuit is reduced, the length and the material of the bonding wire can be set according to the inductance value and the quality factor of the needed inductor, so that the requirements for high inductance value and high quality factor are met, the chip performance is improved, the system cost is reduced; and the inductor can be applied to an oscillator circuit, so that the output frequency is improved, and the phase noise performance is improved, and the application range is expanded.

Description

technical field [0001] The invention relates to an inductor applied to a back-illuminated image sensor chip. Background technique [0002] A back-illuminated image sensor chip is usually connected to a packaging substrate or circuit board by bonding wires, where the image sensor chip includes a semiconductor substrate with opposing front and back sides, where light enters the substrate from the back, and metals used to form interconnected circuits The layer is disposed on the front side of the substrate. With the reduction of the feature size of the integrated circuit process, the area of ​​the integrated circuit chip is getting smaller and smaller, and the reduction of the area means the reduction of the cost. However, the passive components required for integrated circuit design, such as inductors, cannot be reduced to the same extent as transistors. Therefore, the large area of ​​passive components has become a bottleneck for the reduction of integrated circuit chips. I...

AI Technical Summary

Problems solved by technology

The passive components required for integrated circuit design, such as inductors, cannot be reduced to the same extent as transistors. Therefore, the large area of ​​passive components has become a bottleneck for the reduction of integrated circuit chips.

In addition, some circuits have higher requirements on the quality factor Q value of the inductor, so thicker metal is required to make the coil of the inductor, and the use of thick metal requires an additional mask, which increases the production cost

[0003] At present, for the problem that the inductor occupies a large area, it is a simple way to place the inductor outside the chip, but the use of the off-chip inductor reduces the integration of the chip, and at the same time, it also increases the system cost of applying the chip; additional The increased pads are also not conducive to the further reduction of the chip area

In oscillator circuits, in order to avoid the use of inductors, ring oscillators are often used. This oscillator has the disadvantages of low oscillation frequency and poor phase noise, which limits its use in some application scenarios.

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