Image sensor and method for manufacturing the same

Abstract

The present invention discloses an image sensor and a method for manufacturing the same which is capable of increasing the light-collection efficiency of a photodiode. The image sensor comprises: at least one photodiode formed on a semiconductor substrate; multilayer interlayer insulating films formed on the photodiode and stacked in at least two layers so that the density of the upper interlayer insulating film becomes lower than that of the lower interlayer insulating film as the multilayer interlayer insulating films proceed upward; a light shield layer and an element-protecting film sequentially stacked on the multilayer interlayer insulating film; color filter arrays and a flattening layer sequentially stacked on the element-protecting film; and microlenses arranged on the positions corresponding to the color filters on the flattening layer. Therefore, the light-collection efficiency of the photodiode can be increased with an increased transmittance of a vertical light reaching to the photodiode by making the multilayer interlayer insulating films have a lower density as they proceed upward to decrease the refraction angle of the incident light penetrated through the microlenses and color filters.

Description

technical field [0001] The invention relates to an image sensor and a manufacturing method thereof, in particular to an image sensor capable of improving the light collection efficiency of a photodiode and a manufacturing method thereof. Background technique [0002] Generally, an image sensor is a semiconductor device that converts an optical image into an electrical signal. Among image sensors, a charge-coupled device (CCD) is a device in which metal-oxide-silicon (hereinafter referred to as MOS) capacitors are placed closely and charge carriers are stored in the MOS capacitors and transferred. Complementary metal-oxide-semiconductor (hereinafter referred to as CMOS) image sensor adopts CMOS technology, which uses control circuits and signal processing circuits as peripheral circuits to form an array of MOS transistors as many as the number of pixels, and adopts a switching method of sequential detection output . MOS transistors are formed in peripheral circuits as many ...

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Problems solved by technology

[0010] However, if the incident light irradiated onto the photodiodes by the microlens 28 and the color filters 22a, 22b, and 22c is not parallel focused but focused on other optical channels, the photodiodes 12 on the corresponding optical channels cannot sense the light. light or interfere with other adjacent photodiodes 12

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