KR20110070076A

KR20110070076A - Fabricating method image sensor

Info

Publication number: KR20110070076A
Application number: KR1020090126754A
Authority: KR
Inventors: 정오진
Original assignee: 주식회사 동부하이텍
Priority date: 2009-12-18
Filing date: 2009-12-18
Publication date: 2011-06-24

Abstract

PURPOSE: A method for manufacturing an image sensor is provided to minimize plasma damage occurring when an HDP(High Density Plasma) insulating film is formed, thereby increasing the reliability of the image sensor. CONSTITUTION: A photo diode(110) is formed on a semiconductor substrate(100). A first interlayer insulating layer(210) is formed on the semiconductor substrate which includes the photo diode. A metal wire is formed on the first interlayer insulating layer. A second interlayer insulating layer(400) is formed on the first interlayer insulating layer. The second interlayer insulating layer has the structure in which O3 TEOS(Tetra-Ethyl-Ortho-Silicate) and HDP insulating film are laminated.

Description

Fabrication Method Image Sensor

Embodiments relate to a method of manufacturing an image sensor.

The CMOS image sensor outputs each unit pixel by the MOS transistors by forming MOS transistors corresponding to the quantity of unit pixels on the semiconductor substrate using CMOS technology using a control circuit and a signal processing circuit as peripheral circuits. It is a device that adopts a switching method that detects sequentially.

That is, the CMOS image sensor implements an image by sequentially detecting an electrical signal of each unit pixel by a switching method by forming a photodiode and a MOS transistor in the unit pixel.

However, when the metallization layer is formed on the photodiode and the plasma process is performed to form a high density plasma (HDP) oxide film, deterioration of the photodiode occurs due to plasma damage, resulting in deterioration of optical characteristics and dark current. ), The reliability of the image sensor may be degraded.

The embodiment provides a method of manufacturing an image sensor capable of minimizing plasma damage to a photodiode.

In another aspect, a method of manufacturing an image sensor includes forming a photodiode and a gate on a semiconductor substrate; Forming a first interlayer dielectric layer on the semiconductor substrate including the photodiode and gate; Forming a metal wiring on the first interlayer insulating layer; And forming a second interlayer insulating layer on the first interlayer insulating layer on which the metal wiring is formed, wherein the second interlayer insulating layer is formed by stacking an O ₃ TEOS (Tetraethylorthosilicate) and HDP (High density plasma) insulating film. It includes what is formed.

In the method of manufacturing the image sensor according to the embodiment, when the metal wiring layer is formed, the interlayer insulating film is formed by stacking the TEOS film and the HDP insulating film, thereby minimizing the plasma damage of the photodiode by the TEOS film.

That is, by forming a TEOS film under the HDP insulating film, it is possible to minimize the plasma damage generated when the HDP insulating film is formed to improve the reliability of the image sensor.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

In the description of an embodiment according to the present invention, each layer (film), region, pattern or structure may be "on" or "under" the substrate, each layer (film), region, pad or pattern. "On" and "under" include both "directly" or "indirectly" formed through another layer, as described in do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

8 is a side cross-sectional view illustrating an image sensor according to an embodiment.

As shown in FIG. 8, the image sensor according to the embodiment includes a semiconductor substrate 100, a first interlayer insulating layer 210, a first metal wiring layer 500, a second metal wiring layer 600, and a color filter 700. ), The planarization layer 800, and the microlens 900.

A photodiode 110 may be formed on the semiconductor substrate 100, and although not shown in the drawing, a gate may be formed on the semiconductor substrate 100.

The first interlayer insulating layer 210 may be formed of a Boro-Phospho-Silicate-Glass insulating film.

The first metal wiring layer 500 includes a first wiring 300 and a second interlayer insulating layer 400.

The first wiring 300 may include a first barrier pattern 311, a metal pattern 321, and a second barrier pattern 331.

In this case, the first barrier pattern 311 and the second barrier pattern 331 may be formed by stacking Ti and TiN.

The second interlayer insulating layer 400 may be formed by stacking the first TEOS layer 410 and the first HDP insulating layer 420.

The first TEOS film 410 may be formed to a thickness of 100 ~ 1000Å.

The first TEOS layer 410 may prevent damage to the photodiode 110 by plasma when the first HDP insulating layer 420 is formed.

Accordingly, the first TEOS layer 410 may improve the optical characteristics of the image sensor by minimizing the degradation of the photodiode 110 due to the plasma.

The first TEOS layer 410 is disposed between the first interlayer insulating layer 210 and the first HDP insulating layer 420.

Although the plan view is not shown in the drawing, the color filter 700 may be formed in the form of a matrix.

The color filter 700 may be formed with a step for each color, and the planarization layer 800 may eliminate the step.

The microlens 900 may be formed in a matrix form similarly to the color filter 700.

Hereinafter, a manufacturing method of an image sensor will be described with reference to FIGS. 1 to 8.

1 to 8 are side cross-sectional views illustrating a method of manufacturing an image sensor according to an embodiment.

First, as shown in FIG. 1, the photodiode 110 is formed on the semiconductor substrate 100.

The semiconductor substrate 100 may have a low concentration p-type epi layer (not shown) on a high concentration p ++ type silicon substrate.

This may increase the depth of the depletion region of the photodiode due to the low concentration of p epitaxial layer, thereby increasing the photodiode's ability to collect photocharges.

In addition, having a high concentration of p ++ type substrate under the p-type epi layer reduces the random diffusion of photocharges because the charge is recombined before the charge is diffused to neighboring pixel units. This is because the change in the transfer function of the photocharge can be reduced.

Although not shown, a gate for driving the photodiode 110 may be further formed on the semiconductor substrate 100.

Subsequently, as shown in FIG. 2, the first interlayer insulating layer 210, the first barrier layer 310, the metal layer 320 and the second layer are formed on the semiconductor substrate 100 on which the photodiode 110 is formed. The barrier layer 320 is formed.

The first interlayer insulating layer 210 may be formed of a Boro-Phospho-Silicate-Glass (BPSG) insulating film.

The first barrier film 310 and the second barrier film 320 may be formed by stacking Ti and TiN.

The metal layer 320 may be formed of aluminum (Al).

As shown in FIG. 3, the first barrier layer 310, the metal layer 320, and the second barrier layer 320 are patterned to form a first wiring on the first interlayer insulating layer 210. Form 300.

Subsequently, as shown in FIG. 4, a first TEOS film 410 is formed on the first interlayer insulating layer 210 on which the first wiring 300 is formed.

The first TEOS layer 410 may be deposited by chemical vapor deposition using TEOS (Tetraethylorthosilicate) and ozone (O ₃ ).

In more detail, the first TEOS film 410 has a pressure of 100 to 800 Torr and a temperature of 350 to 450 ° C., 1000 to 10,000 sccm for ozone (O ₃ ), 1000 to 10,000 sccm for nitrogen (N ₂ ), and helium (He). ) Can be formed by injecting 1000 ~ 5000sccm, TEOS 100 ~ 10000mgm.

In addition, the first TEOS layer 410 may be formed to a thickness of 100 ~ 1000Å.

The first TEOS layer 410 may prevent damage to the photodiode 110 by plasma when a high density plasma (HDP) insulating layer to be formed later is formed.

5, a first HDP insulating film 420 is formed on the first TEOS film 410 to form a second interlayer insulating layer 400.

The first HDP insulating layer 420 may be formed by a plasma process, and damage may occur to the photodiode 110, which is a lower structure.

However, in the present exemplary embodiment, before forming the first HDP insulating layer 420, the first TEOS layer 410 may be formed to minimize plasma damage transferred to the photodiode 110.

The first HDP insulating film 420 has a pressure of 2 to 10 mTorr and a temperature of 350 to 450 ° C., 50 to 1000 sccm of oxygen (O ₂ ), 100 to 10000 sccm of silane (SiH ₄ ), and 10 to 10 argon (Ar). It can be formed by injecting 1000sccm.

A first HDP insulating film 420 is formed on the first TEOS film 410, and the first TEOS film 410 is disposed between the first interlayer insulating layer 210 and the first HDP insulating film 420. do.

The second interlayer insulating layer 400 is formed on the first wiring 300 to form a first metal wiring layer 500 including the first wiring 300 and the second interlayer insulating layer 400. .

Subsequently, as shown in FIG. 6, a second metal wiring layer 600 is formed on the second interlayer insulating layer 400.

The second metal interconnection layer 600 may be formed of a second interconnection including a barrier layer and a third interlayer dielectric layer, and the third interlayer dielectric layer is also formed of a second TEOS like the second interlayer dielectric layer 400. It can be formed by stacking the film and the second HDL insulating film.

Since the second metal wiring layer 600 is formed in the same manner as the first metal wiring layer 500, the formation method is omitted.

As shown in FIG. 7, a color filter 700 is formed on the second metal wiring layer 600.

In this case, although the plan view is not shown in the drawing, the color filter 700 may be formed in the form of a matrix.

Subsequently, as shown in FIG. 8, the planarization layer 800 and the microlens 900 are formed on the color filter 700.

The microlens 900 may be formed by forming a photoresist pattern for forming a microlens and then performing a reflow process.

As described above, in the image sensor and the method of manufacturing the same according to the embodiment, when the metal wiring layer is formed, the interlayer insulating film is formed by stacking the TEOS film and the HDP insulating film, so that the plasma damage of the photodiode can be minimized by the TEOS film. .

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Claims

Forming a photodiode on the semiconductor substrate;

Forming a first interlayer insulating layer on the semiconductor substrate including the photodiode;

Forming a metal wiring on the first interlayer insulating layer; And

Forming a second interlayer insulating layer on the first interlayer insulating layer on which the metal wiring is formed;

The second interlayer dielectric layer is formed of a stack of O ₃ Tetraethylorthosilicate (TEOS) and high density plasma (HDP) insulating film.

The method of claim 1,

The O ₃ TEOS layer is a method of manufacturing an image sensor comprising a deposited by a chemical vapor deposition using TEOS and ozone (O ₃ ).

3. The method of claim 2,

The O ₃ TEOS layer is a pressure of 100 ~ 800 Torr and a temperature of 350 ~ 450 ℃,

A method for manufacturing an image sensor comprising forming by injecting 1000 to 10,000 sccm in ozone (O ₃ ), 1000 to 10,000 sccm in nitrogen (N ₂ ), 1000 to 5000 sccm in helium (He), and 100 to 10,000 mgm of TEOS.

3. The method of claim 2,

The O ₃ TEOS layer is a manufacturing method of an image sensor comprising a thickness of 100 ~ 1000Å.

The method of claim 1,

The HDP insulating film is at a pressure of 2 ~ 10mTorr and a temperature of 350 ~ 450 ℃,

50 to 1000 sccm of oxygen (O ₂ ), 100 to 10000 sccm of silane (SiH ₄ ), and 10 to 1000 sccm of argon (Ar).

The method of claim 1,

The first interlayer insulating layer is a manufacturing method of an image sensor comprising a BPSG (Boro-Phospho-Silicate-Glass) insulating film.

The method of claim 1,

And the O ₃ TEOS is disposed between the HDP insulating layer and the first interlayer insulating layer.

The method of claim 1,

And the metal wiring is formed by stacking a first barrier layer, a metal layer, and a second barrier layer.

The method of claim 8,

And the first barrier layer and the second barrier layer are formed by stacking Ti and TiN.