Microlens production method

Abstract

Disclosed is a solid-state image capture element which has high effective sensitivity due to increased microlens formation stability, a reduced the gap between adjacent lenses during microlens formation, excellence in the formation of structures layered between lenses, and excellent control of lens curvature. Also disclosed is a production method for the solid-state image capture element. The disclosed production method for a solid-state image capture element wherein microlenses are arranged on a substrate so as to be adjacent to one another comprises: a first step wherein first microlenses are formed on the surface of a substrate leaving a space wherein second microlenses will be provided; and a second step wherein an overcoat material is applied and then dried on the surface of the substrate whereon the first microlenses have been formed, the resulting substrate is then exposed using a greyscale mask, then second microlenses are formed in the space between adjacent first microlenses, by developing the exposed overcoat material.

Description

technical field [0001] The present invention relates to a solid-state imaging device with a microlens and its manufacturing method. Background technique [0002] As a method of forming microlenses on a substrate, various methods have been studied. [0003] As the first method, the following method (melt method, melt method) is well known: forming a photosensitive thermoplastic resin layer for lenses on the light-receiving part color filter of the image sensor, exposing the resin layer using a photomask having a predetermined pattern, After development, a columnar resist pattern layer is formed at the position corresponding to each light-receiving part, and then heat treatment is performed above the softening point of the thermoplastic resin to cause the resin to flow thermally, thereby causing liquid subsidence at the edge of the pattern layer. Drip, thus forming a convex lens. [0004] As a second method, a method (eching back) is known in which a photosensitive resist fi...

AI Technical Summary

Problems solved by technology

[0006] When using the first method of the prior art, since the pattern layer of the photosensitive lens thermoplastic resin is heat-flowed to form a convex lens shape, welding occurs between adjacent lenses in the heat-flow process, which causes a decrease in yield. reason

In addition, if the distance between the lenses is increased to prevent this phenomenon, the yield will be improved, but there is a problem that a gap is generated between the lenses, which leads to a reduction in the aperture ratio, and the performance of the image sensor is reduced.

[0007] The second method also has a thermal flow process, so it has the same concern

However, the gap between adjacent lenses cannot be eliminated in this method

Furthermore, there is the following problem: the microlens array shape with a high aperture ratio, which is considered ideal in terms of light-gathering efficiency, and has overlap between lenses, cannot be obtained.

Images