Method for Manufacturing CMOS Image Sensor

Abstract

A method for manufacturing a CMOS image sensor that independently forms a poly routing line connected to a gate poly of a reset transistor is provided. In an embodiment, a semiconductor substrate is prepared defining a device isolation region and an active region. Subsequently, a plurality of gate polys are formed on a predetermined portion of the active region. A photodiode is formed in a portion of the semiconductor substrate located at one side of one of the plurality of gate polys. After an oxide layer is deposited on the semiconductor substrate including the gate polys, the oxide layer is selectively removed to form oxide layer patterns for exposing a portion of the plurality of gate polys. After a polysilicon layer is deposited on the oxide layer pattern, the polysilicon layer is selectively removed to form a routing line connected to the portion of the plurality of gate polys.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is an equivalent circuit diagram of a general 4T type CMOS image sensor;

FIG. 2 is a lay-out diagram illustrating a unit pixel of a general 4T type CMOS image sensor;

FIG. 3 is a lay-out diagram for illustrating a poly routing method of a CMOS image sensor according to the related art;

FIG. 4 is a lay-out diagram for illustrating another poly routing method of a CMOS image sensor according to the related art;

FIG. 5 is a lay-out diagram illustrating forming an active region and a poly layer in a method for manufacturing a CMOS image sensor according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view along line I-I′ of FIG. 5;

FIGS. 7A to 7C are cross-sectional views illustrating a method for manufacturing a CMOS image sensor according to an embodiment of the present invention; and

FIG. 8 is a lay-out diagram for illustrating a poly routing of a CMOS image sensor according to an embodiment of the present invention.

Claims

1. A method for manufacturing a complementary metal oxide semiconductor image sensor, comprising: preparing a semiconductor substrate where a device isolation region and an active region are defined;forming a plurality of gate polys on a predetermined portion of the active region;forming a photodiode in a portion of the semiconductor substrate located at one side of one of the plurality of gate polys;depositing an oxide layer on the semiconductor substrate including the gate polys, and selectively removing the oxide layer to form oxide layer patterns for opening a predetermined portion of the plurality of gate polys; anddepositing a polysilicon layer on the oxide layer patterns, and selectively removing the polysilicon layer to form a poly routing line connected to the predetermined portion of the plurality of gate polys.

2. The method according to claim 1, wherein the polysilicon layer is formed of silicon doped with impurities.

3. The method according to claim 1, further comprising performing a salicide process on the poly routing line.

4. A method for manufacturing a complementary metal oxide semiconductor image sensor, comprising: forming a photodiode and a plurality of gate polys on a semiconductor substrate;performing a front-end process on the semiconductor substrate having the photodiode and the plurality of gate polys; anddepositing a polysilicon layer to form a poly routing line contacting some of the plurality of gate polys.

5. The method according to claim 4, wherein the polysilicon layer is formed of doped silicon.

6. The method according to claim 4, further comprising performing a salicide process on the poly routing line.