KR20100079247A - Back side illumination image sensor and method for manufacturing the same - Google Patents

Back side illumination image sensor and method for manufacturing the same Download PDF

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KR20100079247A
KR20100079247A KR1020080137674A KR20080137674A KR20100079247A KR 20100079247 A KR20100079247 A KR 20100079247A KR 1020080137674 A KR1020080137674 A KR 1020080137674A KR 20080137674 A KR20080137674 A KR 20080137674A KR 20100079247 A KR20100079247 A KR 20100079247A
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substrate
layer
forming
sensing unit
ion implantation
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KR1020080137674A
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Korean (ko)
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이상기
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주식회사 동부하이텍
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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
    • H01L27/14603—Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
    • H01L27/14607—Geometry of the photosensitive area
    • 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
    • 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
    • H01L27/14689—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
    • 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

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Abstract

PURPOSE: A back side illumination image sensor and a method for manufacturing the same are provided to maximize the amount of incident light by minimizing the lamination of a light receiving layer. CONSTITUTION: A light sensing unit(30) is formed on a pixel region over a substrate. An epi layer(15) is formed on the substrate in which the light sensing unit is formed. An element isolation region(20) is formed in the epi layer. An interlayer dielectric layer(55) and a wiring(50) are formed on the whole of the epi layer. A micro lens is formed on the light sensing unit of a substrate backside.

Description

Back side illumination image sensor and method for manufacturing the same

Embodiments relate to a back-receiving image sensor.

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

In the prior art, a photodiode is formed on a substrate by ion implantation. As the size of the photodiode 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, since the stack height is not reduced as much as the area of the light receiving unit is reduced, the number of photons incident on the light receiving unit is also decreased due to the diffraction phenomenon of light called Airy Disk.

As an alternative to overcome this, an attempt has been made to receive light through the wafer back side to minimize the step difference on the top of the light receiving unit and to eliminate the interference of light due to metal routing (back light receiving image sensor). ought.

The back light receiving image sensor according to the prior art performs a back side grinding process (Back Side Grinding) to remove the back side of the substrate to a predetermined thickness after the wiring process with the light receiving element on the front of the substrate. This is to match the distance between the external module and the optical lens by grinding the back side of the substrate to an appropriate thickness.

However, the conventional back light receiving image sensor uses a silicon on insulator (SOI) wafer as a donor wafer in which a light receiving element and a circuit part are formed, and then uses a handle wafer and bonding. Let's do it. Thereafter, the backside polishing process is performed on the donor wafer.

The backside polishing process of the donor wafer according to the prior art is as follows.

First, donor wafer backside grinding is performed to leave dozens of micrometers on the basis of BOX (Buried Oxide). Thereafter, an etch-back is performed to complete a backside thinning process.

However, in the technology of the conventional back-receiving image sensor, a logic circuit portion and a photodiode (PD) are formed together in a prime wafer, which is a donor wafer, and a back polishing process is performed after an interconnection process. The remaining donor substrate after the back polishing process is so thin that it is difficult to follow-up. Therefore, according to the prior art, there is a problem that a separate process requiring a support plate, which is a handle wafer, is required.

In addition, according to the conventional technology of the back light receiving image sensor, a photodiode PD is formed in a pixel region of a prime wafer, which is a donor wafer, and a readout circuit is provided on one side of the photodiode of the pixel region. As a result, there is a problem in that the fill factor for the pixel area is reduced by the readout circuit area.

In addition, according to the prior art, wafer edge thinning occurs when the donor wafer backside grinding process is performed. Accordingly, in the subsequent etch-back process, the wafer edge chip may have a defect, thereby causing a problem of economic deterioration.

In addition, according to the related art, the wafer center is also exposed to plasma damage during an etch-back process having a thickness of several tens of micrometers, thereby increasing the possibility of deterioration of image sensor performance. There is a problem.

On the other hand, according to the prior art, the photodiode is deposited with amorphous Si, or the readout circuitry is formed on a silicon substrate, and the photodiode is formed on another wafer, and then wafer-to-wafer bonding. (Wafer-to-Wafer Bonding), an image sensor (hereinafter, referred to as a "3D image sensor") is formed in which a photodiode is formed on a readout circuit. The photodiode and lead-out circuit are connected via a metal line.

However, according to the prior art of the 3D image sensor, the wafer bonding with the lead-out circuit formed to the wafer with the photodiode is inevitably carried out. have. For example, according to the related art, a wiring is formed on a lead-out circuit and wafer-to-wafer bonding is performed so that the wiring and the photodiode contact each other, and the wiring and the photodiode are not only properly contacted. Furthermore, ohmic contact between the wiring and the photodiode is difficult. In addition, according to the prior art, there is a problem that a short is generated in the wiring for electrically connecting the photodiode, and there is a research to prevent the short, but there is a problem in that a complicated process is required.

In the conventional BSI (back side illumination) CIS, there is an advantage of improving the signal to noise ratio by increasing the amount of light in the determined pixel size, but the pixel size itself There is a disadvantage that can not be large. The embodiment can increase the pixel size significantly by changing the photo diode design and the formation method at a given pixel pitch, thereby increasing the signal to noise ratio more than the current BSI. In addition, an object of the present invention is to provide a rear light receiving image sensor and a method of manufacturing the same, which can further reduce the pixel size.

In addition, the embodiment provides a back-receiving image sensor and a method of manufacturing the back-receiving image sensor that can secure the mechanical strength necessary to proceed to the subsequent process even after the backside grinding process (BackSide Grinding) without a separate support plate (support plate) To provide.

In addition, the embodiment is to provide a rear light-receiving image sensor and a method of manufacturing the same that can approach the fill factor 100% in the rear light-receiving image sensor.

In addition, the embodiment is to provide a back-receiving image sensor and a method of manufacturing the same that can remove the back side of the substrate stably and efficiently.

In addition, the embodiment can maximize the amount of incident light while minimizing the stack of the light receiving unit by forming a readout circuit on the upper side of the light sensing unit, and prevents interference and reflection of light due to metal routing. The present invention provides a rear light receiving image sensor and a method of manufacturing the same.

According to an embodiment, a rear light receiving image sensor may include a light sensing unit formed in a pixel area of a front side of a substrate; An epitaxial layer formed on the entire surface of the substrate on which the light sensing unit is formed; An isolation region formed in the epi layer; An interlayer insulating layer and wiring formed on the entire surface of the epi layer; And a microlens formed on the light sensing unit of the back side of the substrate.

In addition, the manufacturing method of the rear light-receiving image sensor according to the embodiment comprises the steps of forming an ion implantation layer as a whole on the front (Front Side) of the substrate; Forming a light sensing unit in a pixel region of the substrate on which the ion implantation layer is formed; Forming an epitaxial layer on an entire surface of the substrate on which the light sensing unit is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing the lower side of the substrate based on the ion implantation layer; And forming a microlens on the light sensing unit of the back side of the substrate.

In addition, the manufacturing method of the rear light-receiving image sensor according to the embodiment comprises the steps of forming a light sensing unit in the pixel area of the front (Front Side) of the substrate; Forming an ion implantation layer on the entire surface of the substrate on which the light sensing unit is formed; Forming an epitaxial layer on an entire surface of the substrate on which the ion implantation layer is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing the lower side of the substrate based on the ion implantation layer; And forming a microlens on the light sensing unit of the back side of the substrate.

In addition, the manufacturing method of the rear light-receiving image sensor according to the embodiment comprises the steps of forming a light sensing unit in the pixel area of the front side (Front Side) of the substrate including a buried insulating layer; Forming an epitaxial layer on an entire surface of the substrate on which the light sensing unit is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing a lower side of the substrate based on the buried insulation layer; And forming a microlens on the light sensing unit of the back side of the substrate.

According to an embodiment of a back-receiving image sensor and a method of manufacturing the same, a pixel pitch is given to an area of a photo diode by changing a pixel design and a process of a CIS to which a conventional BSI method is applied. In addition, the signal to noise ratio can be greatly improved, and the current pixel size can be further reduced. In other words, the embodiment extends the photodiode to the lower portion of the device isolation layer, and the fill factor approaches 100% by using an area corresponding to the pixel pitch as the photodiode. You can.

In addition, according to the embodiment, the photodiode is formed on the substrate in order to secure the mechanical strength necessary for the subsequent process even after the backside grinding process (BackSide Grinding) without a separate support plate in the rear light receiving image sensor, After forming the epi layer on the epitaxial layer, the logic layer is formed on the epi layer so that the epi layer plays the same role as the supporting substrate, so that the thickness of the remaining substrate can be kept thick and there is no bonding process of the supporting substrate. There is an effect that can significantly reduce the time and cost of the process.

In addition, according to the embodiment, the back surface of the substrate may be stably and efficiently removed by using an ion implantation technique. In other words, according to the embodiment, back grinding and etching back are not necessary due to the ion implantation and the cleaving, which causes problems such as edge die failure and plasma damage. There is an advantage that does not.

Further, according to the embodiment, since the final grinding on the donor wafer does not proceed, there is an advantage that damage to the light sensing unit and the circuit unit can be prevented.

In addition, according to the embodiment, an epi wafer may be used as a donor wafer, and is easily manufactured without the need for a bonding process in a 3D image sensor that forms a photodiode on the upper side of the circuit. Therefore, there is no problem of bonding, problems of contact, and the like.

In addition, according to the embodiment, the amount of incident light may be maximized by minimizing the stack of the upper part of the light receiving unit, and the light characteristic of the image sensor may be maximized by eliminating interference and reflection of light due to metal routing.

Hereinafter, a back light receiving image sensor and a method of manufacturing the same according to an embodiment will be described in detail with reference to the accompanying drawings.

In the description of the embodiments, where it is described as being formed "on / under" of each layer, it is understood that the phase is formed directly or indirectly through another layer. It includes everything.

The present invention is not limited to the CMOS image sensor, and can be applied to any image sensor such as a CCD image sensor.

(First embodiment)

1 is a cross-sectional view of a rear light receiving image sensor according to a first embodiment.

The rear light receiving image sensor according to the first embodiment includes a light sensing unit 30 formed in a pixel area of a front side of a substrate 10; An epitaxial layer 15 formed on the entire surface of the substrate on which the light sensing unit 30 is formed; An isolation region 20 formed in the epi layer 15; An interlayer insulating layer 55 and a wiring 50 formed on the entire surface of the epitaxial layer 15; And a microlens 70 formed on the light sensing unit 30 on the back side of the substrate 10. Reference numerals in FIG. 1 will be described later in the manufacturing method.

According to the back-receiving image sensor according to the first embodiment and a manufacturing method thereof, the pixel pitch and the pixel pitch of the photodiode are changed by changing the pixel design and process of the CIS to which the conventional BSI method is applied. By greatly increasing the pixel pitch, the signal to noise ratio can be greatly improved, and the current pixel size can be further reduced. In other words, the embodiment extends the photodiode to the lower portion of the device isolation layer, and the fill factor approaches 100% by using an area corresponding to the pixel pitch as the photodiode. You can.

In addition, according to the rear light receiving image sensor according to the first embodiment, in order to ensure the mechanical strength necessary to proceed to the subsequent process even after the back grinding (Back Grinding) without a separate support plate (support plate) in the rear light receiving image sensor The photodiode is formed on the substrate, the epi layer is formed on the substrate, and then the logic circuit part is formed on the epi layer so that the epi layer plays the same role as the supporting substrate, so the substrate remains after the back grinding process. It can maintain the thickness of the thick, there is no bonding process of a separate support substrate has the effect that can significantly reduce the time and cost required for the process.

Hereinafter, a method of manufacturing the rear light receiving image sensor according to the first embodiment will be described with reference to FIGS. 2 to 7.

First, as illustrated in FIG. 2, the ion implantation layer 120 may be formed on the front side of the substrate 10. The substrate 10 may be an epi wafer, but is not limited thereto. In an embodiment, the lower side 10a of the substrate and the upper side 10b of the substrate may be divided based on the ion implantation layer 120.

In the method of manufacturing the back-receiving image sensor according to the first embodiment, an epi wafer may be used as the donor wafer 10. Accordingly, according to the embodiment, the manufacturing cost is compared to the use of the SOI wafer by using the epi wafer. Can significantly reduce.

In the first embodiment, the ion implantation layer 120 may proceed through ion implantation on the front side of the substrate 10. Since the back side of the substrate 10 reaches several hundred μm, ion implantation through the front side is preferable.

That is, since the thickness of the substrate 10 is very thick compared to the ion implantation depth, the ion implantation from the rear surface of the substrate 10 is difficult to proceed. Therefore, by forming the ion implantation layer 120 before the wiring 50 forming process as in the first embodiment, the lower side 10a of the substrate after bonding can be easily removed.

In the first embodiment, the ion implantation layer 120 may be formed by implanting ions such as hydrogen (H) or helium (He) to form an ion implantation layer, but is not limited thereto.

Alternatively, as another example of the first exemplary embodiment, the device isolation region 20 may be formed on the entire surface of the substrate 10, and then the ion implantation layer 120 may be formed.

Alternatively, as another example of the first embodiment, the photosensitive unit 30 may be formed in the pixel area, and then the ion implantation layer 120 may be formed. For example, the light sensing unit 30 may be formed in the pixel area of the front surface of the substrate 10 using the first photoresist pattern 130 as a mask. The light sensing unit 30 may be a photodiode, but is not limited thereto. The light sensing unit 30 may form an N-type ion implantation region on the P-type substrate 10 and form a Po region (not shown) on the N-type ion implantation region of the substrate 10. It is not limited. Excess electrons and the like can be prevented by the Po region. In addition, according to the embodiment, the charge dumping effect may be obtained by forming the PNP X-ray.

Meanwhile, in the first embodiment, the light sensing unit 30 may be formed in the entire pixel area. Thus, according to the embodiment, the fill factor is close to 100% while employing the rear light receiving image sensor. In addition, since the transistor 40 is formed on the epitaxial layer 15 on the upper side of the light sensing unit 30, the transistor 40 has an advantage of significantly increasing the fill factor.

Next, as shown in FIG. 3, the first photoresist layer pattern 130 is removed, and the epitaxial layer 15 is formed on the entire surface of the substrate 10 on which the light sensing unit 30 is formed. The epi layer 15 may be made of the same material as the substrate 10. The epi layer 15 may be a single layer or a plurality of layers.

According to the rear light-receiving image sensor and the manufacturing method thereof according to the first embodiment, the mechanical strength required to proceed to the subsequent process even after the back grinding process (Back Grinding) without a separate support plate in the rear light-receiving image sensor The photodiode is formed on the substrate, and the epi layer 15 is formed on the substrate, and then the lead-out circuit, which is a logic part, is formed on the epi layer 15 so that the epi layer 15 is the same as the supporting substrate. Because it plays a role, the thickness of the remaining substrate can be kept thick, and there is no separate bonding process of the supporting substrate, thereby reducing the time and cost required for the process.

Next, as shown in FIGS. 4 and 5, a lead-out circuit serving as a circuit part is formed on the entire surface of the epi layer 15. The readout circuit may include, but is not limited to, a transistor 40 such as a transfer transistor, a reset transistor, a drive transistor, and a select transistor.

In addition, the readout circuit may further include a plug 80 electrically connected to the light sensing unit 30. The plug 80 may be formed by ion implantation using the second photoresist layer pattern 135 as a mask as shown in FIG. 4, or may form via holes (not shown) in the epitaxial layer 15 and the substrate 10, and the via holes may be metal layers. It can be formed by filling.

An isolation layer 20 may be formed on the epitaxial layer 15, and the epitaxial layer 15 may be formed thicker than the thickness of the isolation layer 20.

The readout circuit may include a conductive well (not shown) connected to the plug 80 to receive optoelectronic information of the light sensing unit 30.

For example, an N + well may be made by a high concentration of N-type ion implantation on a part of the entire surface of the epitaxial layer 15, but is not limited thereto. A conductive well may be formed before the plug 80 is formed.

The readout circuit may include a transistor 40 on one side of the conductive well. The transistor 40 shown in FIG. 5 may be a transfer transistor, but is not limited thereto.

For example, as shown in FIG. 5, electronic information may move to a floating diffusion region (not shown) through the transfer transistor 40 through the plug 80 and the conductive well, but is not limited thereto. For example, the electronic information may be directly transmitted to the gate of the drive transistor (not shown) through the plug 80.

The readout circuit may be formed on an inner side surface or an upper side surface of the epi layer 15. For example, FIG. 5 illustrates an example in which the lead-out circuit is formed on the upper side of the epi layer 15 front surface, but is not limited thereto. That is, the transistor 40 of the readout circuit may form a trench in the entire epi layer 15 and may be formed in the trench.

Thereafter, the interlayer insulating layer 55 may be formed on the entire epitaxial layer 15, and the wiring 50 may be formed on the interlayer insulating layer 55. Thereafter, a protective insulating layer 60 may be further formed on the wiring 50.

Next, as shown in FIG. 6, the lower side 10a of the substrate is removed from the substrate 10 based on the ion implantation layer 120. For example, heat treatment is performed on the ion implantation layer 120 to form hydrogen ions, and the lower side 10a of the substrate is cut and removed by a blade or the like, and the upper side 10b of the substrate remains. You can. Thereafter, a planarization process may be performed on the cut surface of the substrate 10.

On the other hand, in the conventional three-dimensional (3D) image sensor-related patents applying the cleaving technology, the light sensing unit and the lead-out circuit are formed on separate wafers to perform bonding and interconnection processes. The invention is mainstream, and in the prior art, a hydrogen or helium ion implantation process for forming a cleaving layer is performed immediately before bonding.

However, according to the prior art of the 3D image sensor, there is a problem in that the electrical connection between the lead-out circuit and the photodiode is difficult to be made properly, and there is a problem in that short circuit occurs in the wiring for the electrical connection with the photodiode.

On the other hand, in the prior art of the 3D image sensor, the hydrogen or helium ion implantation process is possible just before bonding, so that the electrons generated in the light sensing unit are transferred to the electronic circuit and converted into voltage, so that the photodiode (PD) is used in the light sensing unit. Since only a metal and an interlayer insulating film need to be formed, it is possible.

However, in the first embodiment, the light sensing unit 30 is formed on the substrate 10, which is a wafer, and the lead-out circuit is formed on the epi layer 15 on the upper side thereof. Accordingly, according to the first embodiment, the light sensing unit 30 and the lead-out circuit are formed together in the entire surface direction of the same substrate 10, thereby forming the wiring 50 and the interlayer insulating layer 55, etc. (BEOL) process is essential.

Therefore, when the process scheme of the first embodiment is used, an ion implantation process using hydrogen or helium immediately before bonding as in the prior art is impossible, and the substrate 10 as the donor wafer as in the first embodiment is not possible. The ion implantation layer 120 may be formed by performing a hydrogen or helium ion implantation process before forming the wiring 50 and the interlayer dielectric layer 55 on the epi wafer.

Next, as shown in FIG. 7, the color filter 90 may be formed on the light sensing unit 30 on the rear surface of the substrate 10. On the other hand, when the light sensing unit 30 is an R, G, B vertical stacked photodiode, the color filter may not be formed. Thereafter, the microlens 70 may be formed on the color filter 90. In this case, the insulation layer 65 may be further formed before the color filter 90 is formed.

In an embodiment, the pad plug 100 and the pad 110 may be formed. In this case, the pad plug 80 of the embodiment is illustrated as being connected to the top metal, but is not limited thereto. The pad plug 80 may be connected to the first metal M1.

According to the back-receiving image sensor according to the first embodiment and the manufacturing method thereof, the pixel pitch and the pixel pitch of the photodiode are changed by changing the pixel design and process of the CIS to which the conventional BSI method is applied. By greatly increasing the pixel pitch, the signal to noise ratio can be greatly improved, and the current pixel size can be further reduced. In other words, the embodiment extends the photodiode to the lower portion of the device isolation layer, and the fill factor approaches 100% by using an area corresponding to the pixel pitch as the photodiode. You can.

In addition, according to the first embodiment, the photodiode is formed on the substrate in order to secure the mechanical strength necessary for the subsequent process even after back grinding without a separate support plate in the rear light receiving image sensor. After the epi layer is formed on the substrate, a logic portion is formed on the epi layer so that the epi layer plays the same role as the support substrate, so that the thickness of the remaining substrate can be kept thick, and the bonding process of a separate support substrate is performed. There is no effect that can significantly reduce the time and cost of the process.

In addition, according to the first embodiment, the back surface of the substrate can be removed stably and efficiently by using an ion implantation technique.

Further, according to the first embodiment, since the grinding of the donor wafer does not proceed, there is an advantage that damage to the light sensing unit and the circuit unit can be prevented.

Further, according to the first embodiment, the light sensing unit and the circuit unit can be formed by using an epi wafer as a donor wafer.

In addition, according to the first embodiment, an epi wafer may be used as a donor wafer, and a 3D image sensor for forming a photodiode on the upper side of the circuit by forming a light sensing unit and a circuit unit on the epi wafer. It is easy to manufacture without the need for a bonding process, and thus there is an advantage that there is no bonding problem, no contact problem, and the like.

In addition, according to the first embodiment, the amount of incident light can be maximized by minimizing the stack of the upper part of the light receiving unit, and the optical characteristics of the image sensor can be maximized by eliminating interference and reflection of light due to metal routing. have.

(2nd Example)

8 is a process cross-sectional view of a method of manufacturing a back-receiving image sensor according to a second embodiment.

The second embodiment may employ the features of the manufacturing method of the back-receiving image sensor according to the first embodiment.

Meanwhile, unlike the first embodiment, the second embodiment may remove the lower side of the substrate 10 by backgrinding based on the buried insulation layer 125.

That is, in the second embodiment, the light sensing unit 30 is formed on the substrate 10 including the buried insulating layer 125. Thereafter, an epitaxial layer 15 is formed on the substrate 10 on which the light sensing unit 30 is formed, and a readout circuit is formed on the epitaxial layer 15. Thereafter, an interlayer insulating layer 55 and a wiring 50 are formed on the epitaxial layer 15.

Thereafter, the lower side of the substrate 10 may be removed by backgrinding the lower side of the substrate 10.

According to the second embodiment, a method of greatly increasing the area of a photodiode at a given pixel pitch by changing a pixel design and a process of a CIS to which a conventional BSI method is applied, Not only can the signal to noise ratio be greatly improved, but the current pixel sign can be further reduced. In other words, the embodiment extends the photodiode to the lower portion of the device isolation layer, and the fill factor approaches 100% by using an area corresponding to the pixel pitch as the photodiode. You can.

The present invention is not limited to the described embodiments and drawings, and various other embodiments are possible within the scope of the claims.

1 is a cross-sectional view of a rear light receiving image sensor according to an embodiment.

2 to 7 are process cross-sectional views of a method of manufacturing a back-receiving image sensor according to a first embodiment.

8 is a process cross-sectional view of a method of manufacturing a back-receiving image sensor according to a second embodiment;

Claims (16)

An optical sensing unit formed in the pixel area of the front side of the substrate; An epitaxial layer formed on the entire surface of the substrate on which the light sensing unit is formed; An isolation region formed in the epi layer; An interlayer insulating layer and wiring formed on the entire surface of the epi layer; And a microlens formed on the light sensing unit on the back side of the substrate. According to claim 1, The light sensing unit And a rear light receiving image sensor formed over the entire pixel area of the substrate. According to claim 1, A plug connected to the light sensing unit; And And a transistor formed on a front surface of the epi layer on one side of the plug. The method of claim 3, The transistor is And a rear light receiving image sensor formed on an inner side surface or an upper side surface of the entire epi layer. The method of claim 1, wherein And a color filter formed between the rear surface of the substrate and the microlens. Forming an ion implantation layer as a whole on the front side of the substrate; Forming a light sensing unit in a pixel region of the substrate on which the ion implantation layer is formed; Forming an epitaxial layer on an entire surface of the substrate on which the light sensing unit is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing the lower side of the substrate based on the ion implantation layer; And And forming a microlens on the light sensing unit of the back side of the substrate. Forming a light sensing unit in a pixel area of a front side of a substrate; Forming an ion implantation layer on the entire surface of the substrate on which the light sensing unit is formed; Forming an epitaxial layer on an entire surface of the substrate on which the ion implantation layer is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing the lower side of the substrate based on the ion implantation layer; And And forming a microlens on the light sensing unit of the back side of the substrate. Forming a light sensing unit in a pixel area of a front side of a substrate including a buried insulating layer; Forming an epitaxial layer on an entire surface of the substrate on which the light sensing unit is formed; Forming an isolation region in the epi layer; Forming an interlayer insulating layer and wiring on the entire surface of the epi layer; Removing a lower side of the substrate based on the buried insulation layer; And And forming a microlens on the light sensing unit of the back side of the substrate. The method according to any one of claims 6 to 8, The light sensing unit The method of manufacturing a back-receiving image sensor, characterized in that formed on the entire pixel area of the substrate. The method according to any one of claims 6 to 8, Forming a plug connected to the light sensing unit; And Forming a transistor on the front surface of the epi layer on one side of the plug; manufacturing method of the rear light-receiving image sensor further comprises. The method of claim 10, The transistor is The method of manufacturing a back-receiving image sensor, characterized in that formed on the inner surface or the upper surface of the entire epi layer. The method according to claim 6 or 7, Forming the ion implantation layer is A method for manufacturing a back-receiving image sensor comprising forming an ion implantation layer through hydrogen ion implantation or helium ion implantation. The method according to claim 6 or 7, Forming the ion implantation layer is A method of manufacturing a back-receiving image sensor, characterized in that to form an ion implantation layer by performing ion implantation through the front surface of the substrate. The method according to claim 6 or 7, Removing the lower side of the substrate based on the ion implantation layer, And a lower side of the substrate is removed by heat treatment on the ion implantation layer. The method according to claim 6 or 7, Forming the ion implantation layer is The method of manufacturing a back-light receiving image sensor, characterized in that to form an ion implantation layer as a whole at a predetermined depth on the front of the substrate. The method according to claim 6 or 7, Removing the lower side of the substrate manufacturing method of the back-light receiving image sensor, characterized in that to remove the opposite side of the front side of the substrate on the basis of the ion implantation layer.
KR1020080137674A 2008-12-31 2008-12-31 Back side illumination image sensor and method for manufacturing the same KR20100079247A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101420503B1 (en) * 2012-01-31 2014-07-16 타이완 세미콘덕터 매뉴팩쳐링 컴퍼니 리미티드 Apparatus and Method for Reducing Dark Current in Image Sensors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101420503B1 (en) * 2012-01-31 2014-07-16 타이완 세미콘덕터 매뉴팩쳐링 컴퍼니 리미티드 Apparatus and Method for Reducing Dark Current in Image Sensors
US9379275B2 (en) 2012-01-31 2016-06-28 Taiwan Semiconductor Manufacturing Company, Ltd. Apparatus and method for reducing dark current in image sensors

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