Image sensor

Abstract

Embodiments relate to an image sensor, and are used to directly form microlenses on a color filter layer without forming a separate planarization layer by forming a color filter layer having relatively flat steps. According to an embodiment, a method may include: forming an interlayer dielectric layer on a semiconductor substrate formed together with a plurality of photodiodes; forming a color filter layer on the interlayer dielectric layer; A sacrificial layer is formed on the surface; steps of the color filter layer are flattened by etching the upper surface of the color filter layer and the sacrificial layer; and microlenses are formed on the color filter layer.

Description

[0001] This application claims the benefit of Korean Patent Application No. 10-2006-0136969 filed on December 28, 2006, which is incorporated herein by reference in its entirety. technical field [0002] The present invention relates to an image sensor, and more particularly, to a method for preparing an image sensor including a color filter having flat steps. Background technique [0003] Image sensors may be semiconductor devices that convert optical signals into electrical signals, and may be roughly classified into two types of devices. The first type is a Charge Coupled Device (CCD) image sensor device and the second type is a Complementary Metal-Oxide-Semiconductor (CMOS) image sensor device. [0004] The image sensor may be provided as a pixel unit and may include a photodiode that senses the irradiating light and a logic circuit part that processes the light sensed from the photodiode into an electrical signal to represent the light as data. In general, an increased...

AI Technical Summary

Problems solved by technology

However, this structure can have a disadvantage: as the image sensor pixel unit size decreases, the planarization layer thickness becomes relatively thick

This can degrade the performance of sensing light signals

There may also be a problem that, due to a difference in thickness between a pixel unit in which a color filter layer and a planarization layer can be formed and a logic circuit unit in which a color filter layer and a planarization layer can not be formed, the Streaks such as striation can occur during the coating process

Although an RIE etch-back process can be additionally performed to remove the uneven step, the difference in etch selectivity between the R, G and B color filter layer patterns may be small such that it is practically possible to etch the uneven step back to its original shape

Therefore, its surface cannot be formed flat

Images