US20080023737A1 - Image sensor and method for manufacturing the same - Google Patents
Image sensor and method for manufacturing the same Download PDFInfo
- Publication number
- US20080023737A1 US20080023737A1 US11/878,384 US87838407A US2008023737A1 US 20080023737 A1 US20080023737 A1 US 20080023737A1 US 87838407 A US87838407 A US 87838407A US 2008023737 A1 US2008023737 A1 US 2008023737A1
- Authority
- US
- United States
- Prior art keywords
- gate electrode
- substrate
- layer
- image sensor
- photodiode region
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- 239000000758 substrate Substances 0.000 claims abstract description 34
- 125000006850 spacer group Chemical group 0.000 claims abstract description 19
- 150000004767 nitrides Chemical class 0.000 claims abstract description 15
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 10
- 238000005530 etching Methods 0.000 claims abstract description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 18
- 229910052681 coesite Inorganic materials 0.000 claims description 9
- 229910052906 cristobalite Inorganic materials 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 9
- 229910052682 stishovite Inorganic materials 0.000 claims description 9
- 229910052905 tridymite Inorganic materials 0.000 claims description 9
- 238000005229 chemical vapour deposition Methods 0.000 claims description 8
- 238000000151 deposition Methods 0.000 claims description 7
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 239000005380 borophosphosilicate glass Substances 0.000 claims description 4
- 239000005388 borosilicate glass Substances 0.000 claims description 4
- 239000005360 phosphosilicate glass Substances 0.000 claims description 4
- 238000001020 plasma etching Methods 0.000 claims description 4
- 229910000077 silane Inorganic materials 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 238000000137 annealing Methods 0.000 claims description 2
- 238000005498 polishing Methods 0.000 claims description 2
- 239000005368 silicate glass Substances 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 238000009792 diffusion process Methods 0.000 description 13
- 230000003287 optical effect Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000000875 corresponding effect Effects 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910004205 SiNX Inorganic materials 0.000 description 1
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 238000004380 ashing Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Images
Classifications
-
- 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
- H01L27/14689—MOS based technologies
-
- 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
-
- 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
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification 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
- H01L27/14601—Structural or functional details thereof
- H01L27/14625—Optical elements or arrangements associated with the device
- H01L27/14627—Microlenses
Definitions
- the present invention relates to a method for manufacturing an image sensor, and more particularly, to an image sensor having a gate spacer, which can prevent damage to a photodiode region in the image sensor.
- An image sensor is a semiconductor device that can convert an optical image into an electrical signal.
- a Charge Coupled Device is a device in which individual Metal-Oxide-Silicon (MOS) capacitors are located very close to each other to store and carry charge carriers.
- a CMOS image sensor is a device that has the same number of MOS transistors as the number of pixels and employs a switching method in which outputs are detected sequentially using the MOS transistors.
- the MOS transistors are formed with CMOS technology in which a control circuit and a signal processing circuit are used as peripheral circuits.
- Such an image sensor has a Color Filter Array (CFA) arranged on an optical detection portion that receives external light and generates and stores photo-generated charges.
- the color filter array includes red, green, and blue color filters or yellow, magenta, and cyan color filters.
- the image sensor is composed of an optical detection portion which detects light and a logic circuit portion which processes the detected light into an electrical signal and creates corresponding data.
- a focusing technology has been introduced to change the path of light incident on areas other than the optical detection portion and thus to focus the incident light on the optical detection portion.
- a method of forming microlenses on the color filters in the image sensor is used to accomplish this focusing.
- FIG. 1A is an equivalent circuit diagram of a unit pixel (dashed in the drawing) of a conventional CMOS image sensor.
- the unit pixel includes one photodiode PD and four NMOSs Tx, Rx, Sx, and Dx (specifically, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and a drive transistor Dx).
- the transfer transistor Tx transfers photo-generated charges collected at the photodiode PD to a floating diffusion (FD) region.
- the reset transistor Rx sets voltage at the node to a desired level and discharges charges Cpd to reset the floating diffusion region.
- the drive transistor Dx serves as a source follower buffer amplifier.
- the select transistor Sx is switched to allow addressing.
- Each of the transfer and reset transistors Tx and Rx use a native NMOS transistor.
- Each of the drive and select transistors Dx and Sx uses a normal NMOS transistor.
- Reset transistor Rx is a transistor for Correlated Double Sampling (CDS).
- the unit pixel of the CMOS image sensor As shown in FIG. 1A , light in the visible wavelength range is detected at the photodiode region (PD) using the native transistor and the detected photo-generated charge is transferred to the floating diffusion region (FD) and an electrical signal corresponding to the amount of the photo-generated charge provided to the gate of the drive transistor Dx is output through an output terminal of the unit pixel.
- PD photodiode region
- FD floating diffusion region
- FIG. 1B is a sectional view of a conventional CMOS image sensor device. This figure shows only a portion of the device corresponding to both the photodiode PD and the transfer transistor Tx which transfers photo-generated charges collected at the photodiode PD to the floating diffusion region PD.
- a p-type epitaxial layer 12 doped with a low-concentration p-type impurity is grown on a p+ substrate 11 doped with a high-concentration p-type impurity and a field oxide layer 13 . Separation between unit pixels is formed on a specific portion of the p-type epitaxial layer 12 using a local oxidation of silicon (LOCOS) method.
- LOC local oxidation of silicon
- a gate electrode 14 of a transfer transistor Tx is formed on the p-type epitaxial layer 12 .
- gate electrodes of a drive transistor Dx, a reset transistor Rx, and a select transistor Sx are formed simultaneously at this time.
- n-type diffusion layer 15 is formed in a portion of the p-type epitaxial layer 12 at one side of the gate electrode 14 of transfer transistor Tx by implanting low-concentration n-type impurity ions with high energy into the epitaxial layer 12 .
- An insulation layer for spacers is then deposited over the entire area of the substrate and blank etching is performed on the insulation layer to form a spacer 16 in contact with either sidewall of the gate electrode 14 of the transfer transistor Tx.
- low-energy p-type impurity ions are implanted, for example, using a blanket ion implantation method, to form a p-type diffusion layer 17 in a top portion of the n-type diffusion layer 15 and a surface portion of the p-type epitaxial layer 12 .
- the p-type diffusion layer 17 formed in the n-type diffusion layer 15 is separated from gate electrode 14 as far as the thickness of the spacer 16 .
- a shallow pn junction including the p-type diffusion layer 17 and the n-type diffusion layer 15 is formed through such implantation of low-energy p-type impurity ions.
- a pnp type photodiode including the p-type epitaxial layer 12 , the n-type diffusion layer 15 , and the p-type diffusion layer 17 is formed.
- the photodiode region A may be excessively corroded as shown in FIG. 1C to open the photodiode, thereby causing damage to the image sensor and thus degrading the performance of the image sensor.
- the present invention is directed to an image sensor and a method for manufacturing the same.
- a method for manufacturing an image sensor includes forming a photoresist on a substrate including a photodiode region and a gate electrode opposite to the photodiode region on the basis of the gate electrode; forming an oxide layer to a specific thickness on both the photodiode region and a part of the gate electrode; removing the photoresist from the substrate and cleaning the substrate; forming a first oxide film on the substrate, the gate electrode, and the oxide layer remaining on the photodiode region; forming a nitride film on the first oxide film; forming a second oxide film on the nitride film; and performing blank etching on the first oxide film, the nitride film, and the second oxide film to form a spacer at the side of the gate electrode.
- an image sensor in another aspect, includes a substrate including a photodiode region formed therein; a gate electrode formed on the substrate, the gate electrode being in contact with the photodiode region; an oxide layer with a specific thickness formed on the photodiode region; and a spacer provided at one side of the gate electrode opposite to the oxide layer.
- FIG. 1A is an equivalent circuit diagram of a conventional CMOS image sensor
- FIG. 1B is a sectional view of a conventional CMOS image sensor
- FIG. 1C illustrates damage to a photodiode region that may occur in the conventional CMOS image sensor
- FIGS. 2A to 2 E are sectional views of a procedure for manufacturing an image sensor according to an embodiment of the present invention.
- FIGS. 2A to 2 E are sectional views illustrating a procedure for manufacturing an image sensor according to an embodiment consistent with the present invention.
- the sectional view of FIG. 2A illustrates a photoresist 130 that is coated to a specific thickness on a substrate 100 on one side of a gate electrode 120 formed outside a photodiode region 110 on the substrate 100 .
- the substrate 100 may be one selected from a silicon substrate, a Silicon On Insulator (SOI) substrate, a GaAs substrate, a SiGe substrate, and a ceramic substrate.
- SOI Silicon On Insulator
- the photoresist 130 is coated to a specific thickness on the substrate 100 in an area of the substrate other than the photodiode region 110 as shown in FIG. 2A .
- Oxide layer 140 is then formed to a thickness of 3000-3500 ⁇ on both the photodiode region 110 and a part of the gate electrode 120 as shown in FIG. 2B .
- the oxide layer 140 is formed to a thickness of 3000-3500 ⁇ , for example, by depositing a SiO 2 layer in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber and then performing a Chemical Mechanical Polishing (CMP) process on the SiO 2 layer.
- CVD Chemical Vapor Deposition
- CMP Chemical Mechanical Polishing
- ashing and cleaning processes are performed on the photoresist 130 to remove the photoresist 130 so that only the oxide layer 140 remains on both the gate electrode 120 and the substrate 100 as shown in FIG. 2C .
- a multilayer structure including a first oxide film 141 of the same material as the oxide layer 140 , a nitride film 150 , and a second oxide film 160 is formed on the substrate 100 , the gate electrode 120 , and the oxide layer 140 as shown in FIG. 2D .
- the first oxide film 141 is formed by depositing a SiO 2 film in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber in the same manner as the process of forming the oxide layer 140 .
- the SiO 2 film is then etched so that the first oxide film 141 is shaped with steps on the gate electrode 120 and the oxide layer 140 .
- the nitride film 150 is then formed on the first oxide film 141 formed in this manner.
- the nitride film 150 may be a SiNx film that is formed to a uniform thickness through deposition using SiH 4 , NH 3 , and H 2 at a temperature of 350° C.
- the second oxide film 160 is also formed on the nitride film 150 , by depositing a SiO 2 film in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber in the same manner as the process of forming the oxide layer 140 .
- CVD Chemical Vapor Deposition
- the multilayer structure including the first oxide film 141 , the nitride film 150 , and the second oxide film 160 is formed on the substrate 100 , the gate electrode 120 , and the oxide layer 140 ; blank etching is performed on the multilayer structure using a Reactive Ion Etching (RIE) method to form a spacer 170 on the substrate 100 on the left side of the gate electrode 120 as shown in FIG. 2E .
- RIE Reactive Ion Etching
- the oxide layer 140 with a specific thickness remains on the photodiode region 110 by performing blank etching for forming the spacer 170 with exposing the gate electrode 120 .
- a Pre-Metal Dielectric (PMD) layer (not shown) is formed on both spacer and the oxide layer 140 remaining on the photodiode region 110 by depositing and annealing one material selected from borosilicate glass (BSG), phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), and undoped silicate glass (USG) and then flattening the surface of the PMD layer through a CMP process.
- the PMD layer may be formed of the same material as the remaining oxide layer 140 .
- oxide layer 140 is etched into a specific shape and remains on the photodiode region 110 when the spacer 170 is formed on the substrate 100 , it is possible to prevent the photodiode region from being corroded and thus being exposed, which may occur in the conventional procedure for forming the spacer for the gate electrode, thereby improving the performance of the image sensor.
- an image sensor and a method for manufacturing the same which can prevent a photodiode region from being corroded that may occur through etching in a conventional procedure for forming a gate electrode spacer, thereby solving the problem of exposure of the photodiode region and thus improving the performance of the image sensor.
Abstract
An image sensor and a method for manufacturing the same are provided. In the method, a photoresist is formed on a substrate including a photodiode region and a gate electrode opposite to the photodiode region on the basis of the gate electrode. An oxide layer is formed to a specific thickness on both the photodiode region and a part of the gate electrode. The photoresist is removed from the substrate and cleaned. A first oxide film is formed on the substrate, the gate electrode, and the oxide layer remaining on the photodiode region. A nitride film is formed on the first oxide film. And a second oxide film is formed on the nitride film. Blank etching is performed on the first oxide film, the nitride film, and the second oxide film to form a spacer at the side of the gate electrode.
Description
- This application is based upon and claims the benefit of priority to Korean Patent Application No. 10-2006-68977 filed on Jul. 24, 2006, the entire contents of which are incorporated herein by reference.
- 1. Technical Field
- The present invention relates to a method for manufacturing an image sensor, and more particularly, to an image sensor having a gate spacer, which can prevent damage to a photodiode region in the image sensor.
- 2. Discussion of the Related Art
- An image sensor is a semiconductor device that can convert an optical image into an electrical signal. A Charge Coupled Device (CCD) is a device in which individual Metal-Oxide-Silicon (MOS) capacitors are located very close to each other to store and carry charge carriers. A CMOS image sensor is a device that has the same number of MOS transistors as the number of pixels and employs a switching method in which outputs are detected sequentially using the MOS transistors. Here, the MOS transistors are formed with CMOS technology in which a control circuit and a signal processing circuit are used as peripheral circuits.
- Such an image sensor has a Color Filter Array (CFA) arranged on an optical detection portion that receives external light and generates and stores photo-generated charges. The color filter array includes red, green, and blue color filters or yellow, magenta, and cyan color filters. The image sensor is composed of an optical detection portion which detects light and a logic circuit portion which processes the detected light into an electrical signal and creates corresponding data. Although efforts have been made to increase a fill factor, which is the ratio of the area of the optical detection portion to the entire area of the image sensor, in order to increase optical sensitivity, there are limitations in the efforts with the restricted area since it is not possible to essentially remove the logic circuit portion.
- A focusing technology has been introduced to change the path of light incident on areas other than the optical detection portion and thus to focus the incident light on the optical detection portion. A method of forming microlenses on the color filters in the image sensor is used to accomplish this focusing.
-
FIG. 1A is an equivalent circuit diagram of a unit pixel (dashed in the drawing) of a conventional CMOS image sensor. - As shown in
FIG. 1A , the unit pixel includes one photodiode PD and four NMOSs Tx, Rx, Sx, and Dx (specifically, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and a drive transistor Dx). The transfer transistor Tx transfers photo-generated charges collected at the photodiode PD to a floating diffusion (FD) region. The reset transistor Rx sets voltage at the node to a desired level and discharges charges Cpd to reset the floating diffusion region. The drive transistor Dx serves as a source follower buffer amplifier. The select transistor Sx is switched to allow addressing. - Each of the transfer and reset transistors Tx and Rx use a native NMOS transistor. Each of the drive and select transistors Dx and Sx uses a normal NMOS transistor. Reset transistor Rx is a transistor for Correlated Double Sampling (CDS).
- In the unit pixel of the CMOS image sensor as shown in
FIG. 1A , light in the visible wavelength range is detected at the photodiode region (PD) using the native transistor and the detected photo-generated charge is transferred to the floating diffusion region (FD) and an electrical signal corresponding to the amount of the photo-generated charge provided to the gate of the drive transistor Dx is output through an output terminal of the unit pixel. -
FIG. 1B is a sectional view of a conventional CMOS image sensor device. This figure shows only a portion of the device corresponding to both the photodiode PD and the transfer transistor Tx which transfers photo-generated charges collected at the photodiode PD to the floating diffusion region PD. The following is a brief description of a method for manufacturing an image sensor with reference toFIG. 1B . A p-typeepitaxial layer 12 doped with a low-concentration p-type impurity is grown on ap+ substrate 11 doped with a high-concentration p-type impurity and afield oxide layer 13. Separation between unit pixels is formed on a specific portion of the p-typeepitaxial layer 12 using a local oxidation of silicon (LOCOS) method. - A
gate electrode 14 of a transfer transistor Tx is formed on the p-typeepitaxial layer 12. Although not shown, gate electrodes of a drive transistor Dx, a reset transistor Rx, and a select transistor Sx are formed simultaneously at this time. - An n-
type diffusion layer 15 is formed in a portion of the p-typeepitaxial layer 12 at one side of thegate electrode 14 of transfer transistor Tx by implanting low-concentration n-type impurity ions with high energy into theepitaxial layer 12. An insulation layer for spacers is then deposited over the entire area of the substrate and blank etching is performed on the insulation layer to form aspacer 16 in contact with either sidewall of thegate electrode 14 of the transfer transistor Tx. - Subsequently, low-energy p-type impurity ions are implanted, for example, using a blanket ion implantation method, to form a p-
type diffusion layer 17 in a top portion of the n-type diffusion layer 15 and a surface portion of the p-typeepitaxial layer 12. Here, the p-type diffusion layer 17 formed in the n-type diffusion layer 15 is separated fromgate electrode 14 as far as the thickness of thespacer 16. - A shallow pn junction including the p-
type diffusion layer 17 and the n-type diffusion layer 15 is formed through such implantation of low-energy p-type impurity ions. As a result, a pnp type photodiode including the p-typeepitaxial layer 12, the n-type diffusion layer 15, and the p-type diffusion layer 17 is formed. - In the conventional image sensor including the pnp type photodiode region, blank etching is performed on the insulation layer to form the
spacer 16 in contact with either sidewall of thegate electrode 14 of the transfer transistor Tx as described above. In this case, the photodiode region A may be excessively corroded as shown inFIG. 1C to open the photodiode, thereby causing damage to the image sensor and thus degrading the performance of the image sensor. - Accordingly, the present invention is directed to an image sensor and a method for manufacturing the same.
- Additional features will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The features may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
- There is provided a method for manufacturing an image sensor includes forming a photoresist on a substrate including a photodiode region and a gate electrode opposite to the photodiode region on the basis of the gate electrode; forming an oxide layer to a specific thickness on both the photodiode region and a part of the gate electrode; removing the photoresist from the substrate and cleaning the substrate; forming a first oxide film on the substrate, the gate electrode, and the oxide layer remaining on the photodiode region; forming a nitride film on the first oxide film; forming a second oxide film on the nitride film; and performing blank etching on the first oxide film, the nitride film, and the second oxide film to form a spacer at the side of the gate electrode.
- In another aspect, an image sensor includes a substrate including a photodiode region formed therein; a gate electrode formed on the substrate, the gate electrode being in contact with the photodiode region; an oxide layer with a specific thickness formed on the photodiode region; and a spacer provided at one side of the gate electrode opposite to the oxide layer.
- It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
- 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) consistent with the invention and together with the description serve to explain the invention. In the drawings:
-
FIG. 1A is an equivalent circuit diagram of a conventional CMOS image sensor; -
FIG. 1B is a sectional view of a conventional CMOS image sensor; -
FIG. 1C illustrates damage to a photodiode region that may occur in the conventional CMOS image sensor; and -
FIGS. 2A to 2E are sectional views of a procedure for manufacturing an image sensor according to an embodiment of the present invention. - Reference will now be made in detail to embodiments consistent with the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
-
FIGS. 2A to 2E are sectional views illustrating a procedure for manufacturing an image sensor according to an embodiment consistent with the present invention. The sectional view ofFIG. 2A illustrates aphotoresist 130 that is coated to a specific thickness on asubstrate 100 on one side of agate electrode 120 formed outside aphotodiode region 110 on thesubstrate 100. Thesubstrate 100 may be one selected from a silicon substrate, a Silicon On Insulator (SOI) substrate, a GaAs substrate, a SiGe substrate, and a ceramic substrate. - The
photoresist 130 is coated to a specific thickness on thesubstrate 100 in an area of the substrate other than thephotodiode region 110 as shown inFIG. 2A .Oxide layer 140 is then formed to a thickness of 3000-3500 Å on both thephotodiode region 110 and a part of thegate electrode 120 as shown inFIG. 2B . - The
oxide layer 140 is formed to a thickness of 3000-3500 Å, for example, by depositing a SiO2 layer in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber and then performing a Chemical Mechanical Polishing (CMP) process on the SiO2 layer. - After the
oxide layer 140 is formed in this manner, ashing and cleaning processes are performed on thephotoresist 130 to remove thephotoresist 130 so that only theoxide layer 140 remains on both thegate electrode 120 and thesubstrate 100 as shown inFIG. 2C . - Then, a multilayer structure including a
first oxide film 141 of the same material as theoxide layer 140, anitride film 150, and asecond oxide film 160 is formed on thesubstrate 100, thegate electrode 120, and theoxide layer 140 as shown inFIG. 2D . - First, the
first oxide film 141 is formed by depositing a SiO2 film in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber in the same manner as the process of forming theoxide layer 140. The SiO2 film is then etched so that thefirst oxide film 141 is shaped with steps on thegate electrode 120 and theoxide layer 140. - The
nitride film 150 is then formed on thefirst oxide film 141 formed in this manner. For example, thenitride film 150 may be a SiNx film that is formed to a uniform thickness through deposition using SiH4, NH3, and H2 at a temperature of 350° C. - The
second oxide film 160 is also formed on thenitride film 150, by depositing a SiO2 film in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber in the same manner as the process of forming theoxide layer 140. - After the multilayer structure including the
first oxide film 141, thenitride film 150, and thesecond oxide film 160 is formed on thesubstrate 100, thegate electrode 120, and theoxide layer 140; blank etching is performed on the multilayer structure using a Reactive Ion Etching (RIE) method to form aspacer 170 on thesubstrate 100 on the left side of thegate electrode 120 as shown inFIG. 2E . - The
oxide layer 140 with a specific thickness remains on thephotodiode region 110 by performing blank etching for forming thespacer 170 with exposing thegate electrode 120. A Pre-Metal Dielectric (PMD) layer (not shown) is formed on both spacer and theoxide layer 140 remaining on thephotodiode region 110 by depositing and annealing one material selected from borosilicate glass (BSG), phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), and undoped silicate glass (USG) and then flattening the surface of the PMD layer through a CMP process. The PMD layer may be formed of the same material as the remainingoxide layer 140. - Since
oxide layer 140 is etched into a specific shape and remains on thephotodiode region 110 when thespacer 170 is formed on thesubstrate 100, it is possible to prevent the photodiode region from being corroded and thus being exposed, which may occur in the conventional procedure for forming the spacer for the gate electrode, thereby improving the performance of the image sensor. - As is apparent from the above description, there is provided an image sensor and a method for manufacturing the same which can prevent a photodiode region from being corroded that may occur through etching in a conventional procedure for forming a gate electrode spacer, thereby solving the problem of exposure of the photodiode region and thus improving the performance of the image sensor.
- It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims (11)
1. A method for manufacturing an image sensor, the method comprising:
forming a photoresist on a substrate including a photodiode region and a gate electrode opposite to the photodiode region;
forming an oxide layer on both the photodiode region and a part of the gate electrode;
removing the photoresist from the substrate and cleaning the substrate;
forming a first oxide film on the substrate, the gate electrode, and the oxide layer remaining on the photodiode region;
forming a nitride film on the first oxide film;
forming a second oxide film on the nitride film; and
performing blank etching on the first oxide film, the nitride film, and the second oxide film to form a spacer at the side of the gate electrode.
2. The method according to claim 1 , further comprising forming a Pre-Metal Dielectric (PMD) layer on both the oxide layer remaining on the photodiode region and the spacer formed at the side of the gate electrode.
3. The method according to claim 2 , wherein the PMD layer is formed by depositing and annealing a material selected from borosilicate glass (BSG), phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), and undoped silicate glass (USG) and then flattening a surface of the PMD layer through a Chemical Mechanical Polishing (CMP) process.
4. The method according to claim 1 , wherein the oxide layer includes a SiO2 layer that is formed having a thickness of 3000-3500 Å by depositing SiO2 in a low temperature atmosphere with silane gas in a Chemical Vapor Deposition (CVD) chamber and then performing a CMP process.
5. The method according to claim 1 , wherein the blank etching is performed using a Reactive Ion Etching (RIE) method so that a portion of the oxide layer remains.
6. The method according to claim 2 , wherein the PMD layer is formed using the same material as that of the oxide layer.
7. An image sensor comprising:
a substrate including a photodiode region formed therein;
a gate electrode formed on the substrate, the gate electrode being in contact with the photodiode region;
an oxide layer formed on the photodiode region; and
a spacer provided at one side of the gate electrode opposite to the oxide layer.
8. The image sensor according to claim 7 , further comprising a Pre-Metal Dielectric (PMD) layer that covers the spacer and the substrate.
9. The image sensor according to claim 7 , wherein the oxide layer includes SiO2 and has a thickness of 3000-3500 Å.
10. The image sensor according to claim 7 , wherein the spacer has a multilayer structure including a first oxide film, a nitride film, and a second oxide film that are sequentially layered on both the substrate and one side surface of the gate electrode.
11. The image sensor according to claim 8 , wherein the PMD layer and the oxide layer are formed of SiO2.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/654,489 US7829367B2 (en) | 2006-07-24 | 2009-12-22 | Image sensor and method for manufacturing the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020060068977A KR100806786B1 (en) | 2006-07-24 | 2006-07-24 | Image Sensor and Manufacturing Method Thereof |
KR10-2006-0068977 | 2006-07-24 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/654,489 Division US7829367B2 (en) | 2006-07-24 | 2009-12-22 | Image sensor and method for manufacturing the same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080023737A1 true US20080023737A1 (en) | 2008-01-31 |
Family
ID=38985291
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/878,384 Abandoned US20080023737A1 (en) | 2006-07-24 | 2007-07-24 | Image sensor and method for manufacturing the same |
US12/654,489 Expired - Fee Related US7829367B2 (en) | 2006-07-24 | 2009-12-22 | Image sensor and method for manufacturing the same |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/654,489 Expired - Fee Related US7829367B2 (en) | 2006-07-24 | 2009-12-22 | Image sensor and method for manufacturing the same |
Country Status (2)
Country | Link |
---|---|
US (2) | US20080023737A1 (en) |
KR (1) | KR100806786B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2023168561A1 (en) * | 2022-03-07 | 2023-09-14 | Google Llc | Application of a removable protective film to form a conductive region on a cover glass of a wearable computing device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6166405A (en) * | 1998-04-23 | 2000-12-26 | Matsushita Electronics Corporation | Solid-state imaging device |
US6376868B1 (en) * | 1999-06-15 | 2002-04-23 | Micron Technology, Inc. | Multi-layered gate for a CMOS imager |
US6504195B2 (en) * | 2000-12-29 | 2003-01-07 | Eastman Kodak Company | Alternate method for photodiode formation in CMOS image sensors |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20040008683A (en) * | 2002-07-19 | 2004-01-31 | 주식회사 하이닉스반도체 | A fabricating method of image sensor with decreased dark signal |
KR100494645B1 (en) * | 2002-12-27 | 2005-06-13 | 매그나칩 반도체 유한회사 | Method for fabricating CMOS image sensor with spacer block mask |
KR100719338B1 (en) * | 2004-06-15 | 2007-05-17 | 삼성전자주식회사 | Image sensors and methods of forming the same |
KR100684870B1 (en) * | 2004-12-07 | 2007-02-20 | 삼성전자주식회사 | Cmos image sensor and methods of forming the same |
-
2006
- 2006-07-24 KR KR1020060068977A patent/KR100806786B1/en not_active IP Right Cessation
-
2007
- 2007-07-24 US US11/878,384 patent/US20080023737A1/en not_active Abandoned
-
2009
- 2009-12-22 US US12/654,489 patent/US7829367B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6166405A (en) * | 1998-04-23 | 2000-12-26 | Matsushita Electronics Corporation | Solid-state imaging device |
US6376868B1 (en) * | 1999-06-15 | 2002-04-23 | Micron Technology, Inc. | Multi-layered gate for a CMOS imager |
US6504195B2 (en) * | 2000-12-29 | 2003-01-07 | Eastman Kodak Company | Alternate method for photodiode formation in CMOS image sensors |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2023168561A1 (en) * | 2022-03-07 | 2023-09-14 | Google Llc | Application of a removable protective film to form a conductive region on a cover glass of a wearable computing device |
Also Published As
Publication number | Publication date |
---|---|
US20100173442A1 (en) | 2010-07-08 |
KR100806786B1 (en) | 2008-02-27 |
US7829367B2 (en) | 2010-11-09 |
KR20080009423A (en) | 2008-01-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR100390822B1 (en) | Method for reducing dark current in image sensor | |
KR101439434B1 (en) | Image sensor and method of fabricating the same | |
US9224770B2 (en) | Image sensor device and method | |
KR101425619B1 (en) | treatment method for surface of substrate, method of fabricating image sensor by using the treatment method and image sensor fabricated by the same | |
JP2004214665A (en) | Method of manufacturing cmos image sensor | |
US7741667B2 (en) | CMOS image sensor for improving the amount of light incident a photodiode | |
US7723765B2 (en) | Image sensor having hydrophilic and hydrophobic microlenses and method for manufacturing the same | |
US20080036024A1 (en) | Image sensors and methods of manufacturing the same | |
US7342211B2 (en) | Image sensor and method of manufacturing the same | |
KR101692953B1 (en) | Image Sensor and Method of Manufacturing the same | |
US10497736B2 (en) | Backside illuminated image sensor | |
US20060138484A1 (en) | CMOS image sensor and method for fabricating the same | |
US7829367B2 (en) | Image sensor and method for manufacturing the same | |
US7868364B2 (en) | Image sensor | |
KR100718785B1 (en) | Cmos image sensor, and method for fabricating the same | |
KR20050011955A (en) | Fabricating method of cmos image sensor with protecting microlense capping layer lifting | |
KR20070023418A (en) | Image sensor with enhanced light concentration capability and method for fabrication thereof | |
KR100443348B1 (en) | CMOS Image sensor and method for fabricating the same | |
US20090315087A1 (en) | Image sensor and method for manufacturing the same | |
US7700396B2 (en) | Image sensor and fabricating method thereof | |
KR20060125177A (en) | Cmos image sensor, and method for fabricating the same | |
TWI824874B (en) | Image sensor | |
KR100628229B1 (en) | The complementary metal-oxide-semiconductor image sensor and its manufacturing method for light sensitivity improvement and high integration | |
KR20070036532A (en) | Method for manufacturing cmos image sensor | |
KR20070000818A (en) | Cmos image sensor, and method for fabricating the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DONGBU HITEK CO., LTD., KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HWANG, SANG IL;JANG, JEONG YEL;REEL/FRAME:019663/0755 Effective date: 20070724 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |