KR20100078631A

KR20100078631A - Method for manufacturing image sensor

Info

Publication number: KR20100078631A
Application number: KR1020080136943A
Authority: KR
Inventors: 박지환
Original assignee: 주식회사 동부하이텍
Priority date: 2008-12-30
Filing date: 2008-12-30
Publication date: 2010-07-08

Abstract

In another embodiment, a method of manufacturing an image sensor includes: forming a first photodiode using ion implantation in a first epitaxial layer; First laser annealing the formation region of the first photodiode; Forming a second epitaxial layer on an upper side of the first epitaxial layer on which the first photodiode is formed; Forming a second photodiode using ion implantation in the second epitaxial layer; Second laser annealing of the formation region of the second photodiode; Forming a third epitaxial layer on an upper side of the second epitaxial layer on which the second photodiode is formed; Forming a third photodiode using ion implantation into the third epitaxial layer; And tertiary laser annealing of the formation region of the third photodiode.

Description

Method for Manufacturing Image Sensor

The embodiment relates to a manufacturing method of an image sensor.

Complementary Metal Oxide Silicon (CMOS) image sensor (CIS) is a semiconductor device that converts an optical image into an electrical signal.

In the CIS configuration, when the photodiode area, which receives light signals and converts them into electrical signals, is stacked, the CIS may be configured without a color filter.

Conventional methods for forming a CIS having a stacked photodiode structure include implanting ions into a light-receiving region for receiving red light in a silicon epilayer, and then activating the implanted ions through a thermal process. Form a red photodiode.

Thereafter, epi-Si is grown to form a crystal layer such as a silicon wafer, and a photodiode for receiving green light is formed by performing a thermal process after ion implantation. The above method is repeated to stack the photodiodes for receiving blue light.

According to the conventional method of implementing a stacked photodiode, a lamp heat treatment called a rapid thermal process (RTP) or a furnace heat treatment process is performed for ion activation.

However, the ion implantation defects generated during ion implantation are not likely to be completely removed by the thermal process by RTP or furnace, and the unremoved defects may cause loss of light or disappearance of electrons generated by light. There is a problem that deteriorates the sensitivity and noise characteristics of the diode.

In the embodiment of the present invention, in forming a CIS having a stacked photodiode structure that does not use a color filter, an ion implantation defect generated during ion implantation for forming a photodiode effectively removes the sensitivity of the CIS. It provides a method of manufacturing an image sensor that can improve the.

According to the manufacturing method of the image sensor of the embodiment, in forming a CIS having a stacked photodiode structure without using a color filter, an ion implantation defect generated during ion implantation for forming a photodiode is eliminated. Effective removal can improve the sensitivity of the CIS.

Hereinafter, a manufacturing method of an image sensor according to an exemplary embodiment will be described in detail with reference to the accompanying drawings. However, in describing the embodiments, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, in describing the embodiments, each layer (film), region, pattern, or structure may be “on” or “under” a substrate, each layer (film), region, pad, or pattern. In the case of being described as being formed "in", "on" and "under" include both "directly" or "indirectly" formed. . Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

A method of manufacturing an image sensor according to an embodiment will be described in detail with reference to FIGS. 1 to 6. In the embodiment, the first photodiode is described as a red photodiode, the second photodiode is a green photodiode, and the third photodiode as an example of a blue photodiode, but is not limited thereto.

First, as shown in FIG. 1, the first photodiode 114 is formed by performing an ion implantation process on the first epitaxial layer 110 formed on a predetermined substrate (not shown). For example, an N-type ion implantation into a P-type first epitaxial layer 110 to form a red photodiode 114 for receiving a red light of a stacked photodiode. (implantation) process is performed.

In the ion implantation process for forming the red photodiode 114, the first laser annealing is performed to sufficiently melt-recrystallize the implanted region. Through the primary laser annealing process, the implanted ions are fully activated and defects due to ion implantation can be completely eliminated. In order to sufficiently perform melt-recrystallization, it is preferable to perform scanning while maintaining energy of about 1000 to 2000 mJ / cm 2 during the primary laser annealing.

Meanwhile, before forming the first photodiode 114, the first barrier layer 112 may be formed by implanting P-type ions for pixel separation into the upper portion of the first epitaxial layer 110.

Next, as shown in FIG. 2, a second epitaxial layer 116 is formed on the first photodiode 114 of the first epitaxial layer 110. The second epitaxial layer 116 may be formed of a crystal layer such as a silicon wafer by depositing silicon by CVD. In this case, the second epi layer 116 is formed of a Si epi layer.

After the second epitaxial layer 116 is formed, the second barrier layer 118 may be formed by implanting P-type ions for pixel separation into a portion of the upper part.

Next, as shown in FIG. 3, a second photodiode 122 is formed in the second epitaxial layer 116. The second photodiode 122 may be a green photodiode.

In order to form the green photodiode 122, an N-type implantation process is performed on the P-type second barrier layer 118 and a second laser annealing process is performed. During the secondary laser annealing process, the scan is performed by maintaining the energy at about 1000 to 2000 mJ / cm 2 so that the ion implanted region is sufficiently melt-recrystallized. Thus, the implanted ions are fully activated, and defects due to ion implantation can be completely removed.

Thereafter, an ion implantation step of the first plug 120 electrically connected to the first photodiode 114 of the first epitaxial layer 110 may be performed. For example, the first plug 120 electrically connected to the red photodiode 114 may be formed by N-type ion implantation, and the first plug 120 may be formed by a plurality of ion implantation. .

Next, as shown in FIG. 4, a third epitaxial layer 126 is formed on the second photodiode 122 of the second epitaxial layer 116. The third epitaxial layer 126 may be formed of a crystal layer such as a silicon wafer by depositing silicon by CVD. In this case, the third epitaxial layer 126 is formed of a silicon epitaxial layer.

Next, as shown in FIG. 5, the third photodiode 130 is formed in the third epitaxial layer 126. Here, the third photodiode 130 may be a blue photodiode.

In order to form the blue photodiode 130, an N-type ion implantation process is performed on the third epitaxial layer 126 and a third laser annealing process is performed. During the tertiary laser annealing process, the scan is performed while maintaining the energy at about 1000 to 2000 mJ / cm 2 so that the ion implanted region is sufficiently melt-recrystallized. Thus, the implanted ions are fully activated, and defects due to ion implantation can be completely removed.

Thereafter, an ion implantation step of the second plug 132 electrically connected to the first plug 120 may be performed. The second plug 132 may be formed by a plurality of ion implantation.

The embodiment may proceed with the ion implantation step of the third plug 134 electrically connected to the second photodiode 122 in the ion implantation step of the second plug 132.

Next, as shown in FIG. 6, the device isolation region 128 is formed in the third epitaxial layer 126. For example, the isolation region 128 may be formed by shallow trench isolation (STI), but is not limited thereto.

As described above, the embodiment of the present invention, in the ion implantation step for forming the photodiode 114, 122, 130 in each epi layer (110, 116, 126), the laser at an energy of 1000 ~ 2000mJ / cm The annealing process is performed to sufficiently melt-recrystallize the implanted region, thereby fully activating the implanted ion and completely eliminating ion implantation defects.

Although described above with reference to the embodiment is only an example and is not intended to limit the invention, those of ordinary skill in the art to which the present invention does not exemplify the above within the scope not departing from the essential characteristics of this embodiment 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.

1 to 6 are process cross-sectional views of a manufacturing method of an image sensor according to an embodiment.

Claims

Forming a first photodiode using ion implantation in the first epitaxial layer;

First laser annealing the formation region of the first photodiode;

Forming a second epitaxial layer on an upper side of the first epitaxial layer on which the first photodiode is formed;

Forming a second photodiode using ion implantation in the second epitaxial layer;

Second laser annealing of the formation region of the second photodiode;

Forming a third epitaxial layer on an upper side of the second epitaxial layer on which the second photodiode is formed;

Forming a third photodiode using ion implantation into the third epitaxial layer;

And tertiary laser annealing of the region in which the third photodiode is formed.

The method of claim 1,

The first, second, third laser annealing process,

Method of manufacturing an image sensor comprising the step of performing a scan by maintaining the laser energy to 1000 ~ 2000mJ / cm2.

The method of claim 1,

Forming the second epitaxial layer and the third epi layer,

Method of manufacturing an image sensor comprising the step of depositing a silicon (Si) epi layer.

The method of claim 1,

Forming a first photodiode using ion implantation in the first epitaxial layer,

Before forming the first photodiode, forming a first barrier layer for pixel separation by implanting P-type ions into an upper side of the first epilayer.

The method of claim 1,

Forming a second photodiode using ion implantation in the second epitaxial layer,

Before forming the second photodiode, forming a second barrier layer for pixel separation by implanting P-type ions into an upper side of the second epilayer.

The method of claim 5,

And forming a first plug electrically connected to the first photodiode.

The method of claim 6,

Forming a third photodiode using ion implantation in the third epitaxial layer,

Forming a second plug in electrical connection with the first plug;

A method of manufacturing an image sensor comprising forming an isolation region.