KR930024180A - Image sensor and its manufacturing method - Google Patents

Abstract

The present invention relates to an image sensor, comprising: sequentially depositing an oxide film and a first silicon nitride film on a semiconductor substrate to form a transfer gate dielectric layer; and forming a first transfer gate electrode on the transfer gate dielectric layer. Forming a transfer gate electrode, forming a thermal oxide film on the entire surface of the first transfer gate electrode, and wet etching the first silicon nitride film on which the first transfer gate electrode and the thermal oxide film are not formed. And removing the second silicon nitride film on the entire surface of the resultant, and forming a second transfer gate electrode on the second silicon nitride film. Therefore, according to the process configuration and cross-sectional shape of the present invention, the thermal oxide film and the silicon nitride film are formed as the insulating oxide on the transfer gate electrode to solve the weakness of the DC leakage current, and also the upper portion of the dielectric layer between the transfer gate electrodes. After removing the silicon nitride film and reforming the silicon nitride film on the entire surface of the substrate, the transfer charge amount caused by contamination by the post-process of the silicon nitride film, which is a conventional problem, or the thickness of the dielectric layers of the first and second transfer gate electrodes becomes uneven. Since it can prevent the electrical characteristics of the device is improved, manufacturing yield is improved.

Description

Image sensor and its manufacturing method

Since this is an open matter, no full text was included.

2A to 2D are cross-sectional views illustrating a method for forming a transfer gate electrode of an image sensor according to an exemplary embodiment of the present invention.

Claims (10)

Forming a transfer gate dielectric layer by sequentially depositing an oxide film and a first silicon nitride film on a semiconductor substrate, and forming a first transfer gate electrode on the transfer gate dielectric layer, on the entire surface of the first transfer gate electrode. Forming a thermal oxide film, removing the first silicon nitride film on which the first transfer gate electrode and the thermal oxide film is not formed by wet etching, redepositing a second silicon nitride film on the entire surface of the resultant, And forming a second transfer gate electrode on the second silicon nitride film. The method of claim 1, wherein the oxide film is formed to a thickness of 10 kV to 2000 kV. The method of claim 1, wherein the first and second silicon nitride films are formed by CVD or FECVD. The method of claim 1, wherein the thickness of the second silicon nitride film is equal to the thickness of the first silicon nitride film. The method of claim 4, wherein the first and second silicon nitride films are formed in a thickness of 60 μs to 2000 μs. The method of claim 1, wherein etching the first silicon nitride film is performed by phosphoric acid. The method of claim 6, wherein a portion of the first silicon nitride layer may be wet-etched with phosphoric acid after dry etching to reduce side etching of the first silicon nitride layer. A dielectric layer of first and second transfer gate electrodes comprising an oxide film and a first or second silicon nitride film is disposed on a semiconductor substrate, and a first transfer gate electrode capped with a thermal oxide film is disposed on the dielectric layer. And a second silicon nitride film interposed as an insulating layer between the second transfer gate and the second transfer gate electrode capped by the thermal oxide film. The method of claim 8, wherein the dielectric layer of the first transfer gate electrode is formed of an oxide film and a first silicon nitride film. The method of claim 8, wherein the dielectric layer of the second transfer gate electrode comprises an oxide film and a second silicon nitride film. ※ Note: The disclosure is based on the initial application.