KR20100080210A - Image sensor and manufacturing method of image sensor - Google Patents

Image sensor and manufacturing method of image sensor Download PDF

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Publication number
KR20100080210A
KR20100080210A KR1020080138856A KR20080138856A KR20100080210A KR 20100080210 A KR20100080210 A KR 20100080210A KR 1020080138856 A KR1020080138856 A KR 1020080138856A KR 20080138856 A KR20080138856 A KR 20080138856A KR 20100080210 A KR20100080210 A KR 20100080210A
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KR
South Korea
Prior art keywords
insulating layer
photodiode
forming
substrate
layer
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KR1020080138856A
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Korean (ko)
Inventor
김영미
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주식회사 동부하이텍
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Priority to KR1020080138856A priority Critical patent/KR20100080210A/en
Publication of KR20100080210A publication Critical patent/KR20100080210A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/1462—Coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14636—Interconnect structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14685—Process for coatings or optical elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/1469—Assemblies, i.e. hybrid integration
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14692—Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon

Abstract

In another embodiment, a method of manufacturing an image sensor includes: forming a first insulating layer including a metal wiring, a ground layer, and a pad on a first substrate on which a readout circuit is formed; Coupling a second substrate on the first insulating layer, and forming a photodiode on the second substrate; Forming a plurality of PTIs on the photodiode; Allowing the PTI to be buried to form a second insulating layer over the photodiode; And forming a trench in the second insulating layer to expose the photodiode and the ground layer, and forming a reset line on the second insulating layer including the trench.

According to an embodiment, the photodiode region and the PTI structure are isolated without removing the donor substrate on the lead-out circuit where the photodiode is not formed, thereby eliminating the interference caused by the refraction of light, and then performing the subsequent process such as the via process. There is an effect that can prevent the occurrence of a defect.

Description

Image sensor and manufacturing method of image sensor

Embodiments relate to an image sensor and a method for manufacturing the image sensor.

An image sensor is a semiconductor device that converts an optical image into an electrical signal, and is divided into a charge coupled device (CCD) and a CMOS image sensor (CIS). do.

In the prior art, a photodiode is formed on a substrate by ion implantation. However, as the size of the photodiode gradually decreases for the purpose of increasing the number of pixels without increasing the chip size, the image quality decreases due to the reduction of the area of the light receiver.

In addition, a method of increasing the electron generation rate by increasing the capacitance of the photodiode has been considered, but there is a limit to extending the depletion region of the photodiode to increase the capacitance, and is formed by a back end process of the photodiode. The light opening ratio is lowered by the structure.

One alternative to overcome this is to deposit photodiodes with amorphous Si, or read-out circuitry using wafer-to-wafer bonding such as silicon substrates. And a photodiode on another substrate above the readout circuit (referred to as " three-dimensional image sensor ", " PD-up CIS ") have been attempted.

This structure is achieved by sequentially forming n + regions, p− regions, and p0 regions in the photodiode region of the other substrate defined as the device isolation film.

According to such a structure, the photo-opening ratio can be improved, and as the depletion region (p- region) of the photodiode is extended, a large value of capacitance can be realized to obtain a high electron generation rate.

1 to 4 are process diagrams illustrating a method of manufacturing an image sensor having a three-dimensional structure. The metal wiring 11, the ground layer 12, and the pad are formed on a main substrate (not shown) on which a readout circuit is formed as shown in FIG. 1. (13) The first insulating layer 10 having the same and the second insulating layer 20 having the contact plugs 22 formed thereon are formed thereon, and the amorphous silicon layer 30 is formed thereon.

After the donor substrate is bonded thereon, an ion implantation process is performed to form the photodiode 40.

As shown in FIG. 2, a hard mask 50 is formed on the photodiode 40 and an etching process is performed to form PTI (Pixel Trench Isolation) as shown in FIG. 3.

The photodiode 40 is not formed on the ground layer 12 and the pad 13, that is, on the main substrate on which the lead-out circuit is located. Light is refracted through the region and the photodiode ( 40) may cause interference.

Therefore, as shown in FIG. 3, the donor substrate 40 on the ground layer 12 and the pad 13 is removed while the PTI process is performed.

Subsequently, the PTI is buried to form a third insulating layer 60.

As shown in FIG. 4, trenches are formed in the third insulating layer 60 and the hard mask 50 to expose the photodiode 40 and the ground layer 12 separated by pixels, and include the trenches. As a result, a reset line 70 is formed on the third insulating layer 60.

An oxide layer 80 is formed on the reset line 70, and a SiN layer 90 is formed thereon.

As described above, since the stepped portion is formed by removing the area of the donor substrate 40 on the ground layer 12 and the pad 13, the photodiode 40, the pad 13, and the like are subsequently removed. In the process of the via process to connect with the metal wiring, defocus occurs during the photo process.

Therefore, as illustrated in FIG. 5, the via hole formed on the photodiode 40 has a normal shape, whereas the via hole formed in the step A does not open, but has an abnormal shape. have.

Embodiments relate to a three-dimensional image sensor, wherein a step is formed in a donor substrate on a readout circuit in which a photodiode is not formed, thereby preventing a defect from occurring in a subsequent process such as a via process. It provides a method for producing.

An image sensor according to an embodiment includes a first substrate on which a readout circuit is formed; A first insulating layer formed on the first substrate and including a metal wiring, a ground layer, and a pad; A second substrate coupled to the first insulating layer, a photodiode formed, and a plurality of PTIs formed thereon; A second insulating layer formed on the photodiode so that the PTI is buried; And a reset line formed on the second insulating layer, including a trench formed in the second insulating layer to expose the photodiode and the ground layer.

In another embodiment, a method of manufacturing an image sensor includes: forming a first insulating layer including a metal wiring, a ground layer, and a pad on a first substrate on which a readout circuit is formed; Coupling a second substrate on the first insulating layer, and forming a photodiode on the second substrate; Forming a plurality of PTIs on the photodiode; Allowing the PTI to be buried to form a second insulating layer over the photodiode; And forming a trench in the second insulating layer to expose the photodiode and the ground layer, and forming a reset line on the second insulating layer including the trench.

According to an embodiment, the photodiode region and the PTI structure are isolated without removing the donor substrate on the lead-out circuit where the photodiode is not formed, thereby eliminating the interference caused by the refraction of light, and then performing the subsequent process such as the via process. There is an effect that can prevent the occurrence of a defect.

With reference to the accompanying drawings, it will be described in detail with respect to the image sensor and the manufacturing method of the image sensor according to the embodiment.

Hereinafter, in describing the embodiments, detailed descriptions of related well-known functions or configurations are deemed to unnecessarily obscure the subject matter of the present invention, and thus only the essential components directly related to the technical spirit of the present invention will be referred to. .

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.

6 is a side cross-sectional view showing the shape of an image sensor after the photodiode 240 is formed according to the embodiment.

Although not shown in FIG. 6, an isolation layer is formed on the first substrate to define an active region, and a readout circuit is formed in the active region.

For example, the first substrate may be a P-type silicon substrate, and the readout circuit may include a transfer transistor, a reset transistor, a drive transistor, a select transistor, and a floating diffusion layer. and a floating diffusion layer).

Subsequently, as shown in FIG. 6, first insulating layers 100 and 200 including metal wiring 110, ground layer 120, pad 130, and the like are formed on the first substrate. 100 and 200 may form a plurality of stacked structures.

The region where the metal line 110 is formed is a region where a photodiode (FIG. 9; 240) is to be formed later, and the region where the ground layer 120 and the pad 130 are formed is a lead-out circuit region of the first substrate. The area corresponding to.

Subsequently, an amorphous Si layer 230 is formed on the first insulating layer 200.

When the amorphous silicon layer 230 is formed, the second substrate 240 is bonded thereon.

The second substrate 240 may be an active silicon substrate in a wafer state, and the surface energy of the bonding surface may be increased by activating the plasma prior to bonding the second substrate 240.

The amorphous silicon layer 230 functions to improve the bonding force of the bonding interface.

Subsequently, the ion implantation process is performed in sequence to form a high concentration P-type conductive layer to be used as ground, a low concentration N-type conductive layer to be used as a light receiving unit, a high concentration N-type conductive layer to contribute to ohmic contact, and a hydrogen ion layer to the second substrate 240. Form.

Thereafter, the hydrogen ion layer is changed to a hydrogen gas layer through heat treatment, and the remainder of the second substrate 240 except for the conductive layers is removed using a blade or the like based on the hydrogen gas layer.

Thus, the photodiode 240 as shown in FIG. 6 may be completed.

7 is a side cross-sectional view showing the shape of an image sensor after the hard mask is formed according to the embodiment.

Referring to FIG. 7, a hard mask 50 is formed on the photodiode 240, and a plurality of PTIs are formed.

In this case, although the photodiode is not required on the ground layer 120 and the pad 130, that is, on the first substrate on which the readout circuit is located, the photodiode is excluded to exclude the stepped structure as described above. Do not remove the 240 area.

Instead, one or more PTIs may be formed in a region of the photodiode 240 on the first substrate on which the readout circuit is formed to function as a light blocking layer.

Accordingly, the photodiode 240 region corresponding to the readout circuit and the photodiode 240 region to be used as the light receiving unit may be isolated by the PTI and interference may be prevented.

8 is a side cross-sectional view illustrating a shape of an image sensor after the second insulating layer 260 is formed according to the embodiment.

Thereafter, as shown in FIG. 8, the PTI is buried to form a second insulating layer 260 on the hard mask 250.

The hard mask 250 is formed of a transparent TEOS (Tetraethyl orthosilicate; Si (C2H5O4)) material and may remain without being removed because it does not interfere with the optical path. However, in some cases, the hard mask 250 may be removed.

9 is a side cross-sectional view illustrating a shape of an image sensor after the fourth insulating layer 290 is formed according to an embodiment.

Referring to FIG. 9, trenches are formed in the second insulating layer 260 and the hard mask 250 to expose the photodiode 240 and the ground layer 220 separated by pixels, and the trenches may be formed. To form a reset line 270 on the second insulating layer 260.

Subsequently, a third insulating layer 280 for insulating the reset line 270, for example, an oxide layer, is formed on the second insulating layer 270 including the reset line 270, and the third insulating layer ( The fourth insulating layer 290, for example, a SiN layer, is formed on the 280.

Thereafter, a microlens (not shown) is formed on the fourth insulating layer 290 on the photodiode 240 separated for each pixel, and the fourth insulating layer 290 has a function of alleviating interlayer stress. do.

The present invention has been described above with reference to preferred embodiments thereof, which are merely examples and are not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. 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 4 are process diagrams illustrating a method of manufacturing an image sensor having a three-dimensional structure.

5 is a view comparing vias formed in stepped areas and non-stepped areas of the image sensor, respectively.

6 is a side cross-sectional view showing the form of an image sensor after the photodiode according to the embodiment is formed;

7 is a side cross-sectional view showing the form of an image sensor after the hard mask is formed according to the embodiment;

8 is a side sectional view showing the shape of an image sensor after a second insulating layer is formed according to the embodiment;

9 is a side sectional view showing the form of an image sensor after the fourth insulating layer is formed according to the embodiment;

Claims (17)

Forming a first insulating layer including a metal wiring, a ground layer, and a pad on the first substrate on which the readout circuit is formed; Coupling a second substrate on the first insulating layer, and forming a photodiode on the second substrate; Forming a plurality of PTIs on the photodiode; Allowing the PTI to be buried to form a second insulating layer over the photodiode; And And forming a trench in the second insulating layer to expose the photodiode and the ground layer, and forming a reset line on the second insulating layer including the trench. The method of claim 1, And forming an amorphous silicon layer on the first insulating layer. The method of claim 1, wherein forming the photodiode Forming a high concentration P-type conductive layer from below the second substrate; Forming a low concentration N-type conductive layer on the high concentration P-type conductive layer; Forming a high concentration N-type conductive layer on the low concentration N-type conductive layer; Forming a hydrogen ion layer on the high concentration N-type conductive layer; And removing the remaining portion of the second substrate based on the hydrogen ion layer. The method of claim 1, wherein forming the PTI is At least one PTI is formed in the photodiode region on the first substrate on which the readout circuit is formed. The method of claim 1, wherein forming the PTI is A hard mask is formed on the photodiode, and the PTI is formed by performing an etching process using the mask as a mask. The method of claim 5, wherein the hard mask is Method of manufacturing an image sensor comprising a TEOS material. The method of claim 1, And forming a third insulating layer on the reset line. The method of claim 7, wherein And a fourth insulating layer is formed on the third insulating layer. The method of claim 7, wherein the third insulating layer A method of manufacturing an image sensor comprising an oxide material. The method of claim 8, wherein the fourth insulating layer The manufacturing method of the image sensor characterized by including SiN. A first substrate on which a readout circuit is formed; A first insulating layer formed on the first substrate and including a metal wiring, a ground layer, and a pad; A second substrate coupled to the first insulating layer, a photodiode formed, and a plurality of PTIs formed thereon; A second insulating layer formed on the photodiode so that the PTI is buried; And a reset line formed over the second insulating layer, including a trench formed in the second insulating layer to expose the photodiode and the ground layer. The method of claim 11, The image sensor further comprises an amorphous silicon layer formed on the first insulating layer. The method of claim 11, wherein the PTI is And at least one photodiode region on the first substrate on which the readout circuit is formed. The method of claim 11, And a third insulating layer formed on the reset line. The method of claim 14, And a fourth insulating layer formed on the third insulating layer. The method of claim 14, wherein the third insulating layer is An image sensor comprising an oxide material. The method of claim 15, wherein the fourth insulating layer An image sensor comprising SiN.
KR1020080138856A 2008-12-31 2008-12-31 Image sensor and manufacturing method of image sensor KR20100080210A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107195649A (en) * 2017-06-06 2017-09-22 豪威科技(上海)有限公司 Back-illuminated cmos image sensors and its manufacture method
CN108470711A (en) * 2018-02-12 2018-08-31 上海集成电路研发中心有限公司 The manufacturing method thereof of imaging sensor and its deep trench and silicon hole

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107195649A (en) * 2017-06-06 2017-09-22 豪威科技(上海)有限公司 Back-illuminated cmos image sensors and its manufacture method
CN107195649B (en) * 2017-06-06 2019-09-17 豪威科技(上海)有限公司 Back-illuminated cmos image sensors and its manufacturing method
CN108470711A (en) * 2018-02-12 2018-08-31 上海集成电路研发中心有限公司 The manufacturing method thereof of imaging sensor and its deep trench and silicon hole

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