JP2005260077A - Solid-state image pickup element, its manufacturing method and camera using element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image pickup element in which a bonding leak is hard to occur although silicide is formed and a S/N ratio can be improved, and to provide a manufacturing method of the element and a camera using the element. <P>SOLUTION: The solid-state image pickup element 20 is formed with a photoelectric conversion region 1 formed in a substrate 6, a transfer gate 2 for transferring charge converted in the photoelectric conversion region 1, a detection capacity part 3 accumulating charge transferred from the photoelectric conversion region 1 by applying a voltage to the transfer gate 2 and a MOS transistor 13 which signal-processes charge accumulated in the detection capacity part 3. Silicides 9 are formed only on the transfer gate 2 formed above the substrate 6 and a gate 5 of the MOS transistor 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solid-state imaging device that converts received light into an electrical signal and outputs it as a video signal.

  FIG. 7 is a cross-sectional view showing a configuration of a MOS type image pickup device which is one of conventional solid-state image pickup devices. As shown in FIG. 7, the solid-state imaging device 100 is formed between a light detection unit 112 and a transistor unit 113 that is a MOS transistor, and an element isolation that electrically separates the light detection unit 112 and the transistor unit 113. Region 111.

  The light detection unit 112 includes a photoelectric conversion region 101 that converts light into electric charge, a transfer gate 102 that transfers a charge in the photoelectric conversion region 101 to the detection capacitor unit 103 by applying a voltage, and a photoelectric conversion region 101. And a detection capacitor unit 103 for accumulating the charges transferred from. Further, the transistor portion 113 includes a gate 105, a drain region 107, and a source region 108.

  Further, silicide 109 is formed on the transfer gate 102 and the detection capacitor 103 of the light detection unit 112 and on the gate 105, the drain region 107, and the source region 108. Further, an oxide film 115 is partially formed on the substrate 106, and sidewalls 117 are formed on the transfer gate 102 and the gate 105.

  Further, the light detection unit 112, the transistor unit 113, and the element isolation region 111 are formed on the substrate 106. Such a solid-state imaging device 100 converts the light detected by the light detection unit 112 into an electric signal and performs signal processing in the transistor unit 113.

  FIG. 8A to FIG. 8D are cross-sectional process diagrams for illustrating a conventional method for manufacturing a solid-state imaging device. As shown in FIG. 8A, the photodetection portion 112 and the transistor portion 113 are formed on the substrate 106, the oxide film 115 is formed on the entire surface, and the transfer gate 102 and the gate 105 are further formed. Next, as shown in FIG. 8B, an insulating deposition film 104 is formed on the entire surface. Next, as shown in FIG. 8C, the insulating deposition film 104 and the oxide film 115 above the transistor portion 113 and the element isolation region 111 are removed, and a part of the insulating deposition film 104 on the transfer gate 102 is removed. To do. Further, part of the oxide film 115 on the detection capacitor 103 is also removed. For the removal, for example, dry etching is used. At this time, the transfer gate 102 and the side wall 117 of the gate 105 are formed. Thereafter, ion implantation is performed.

  Further, as shown in FIG. 8D, a metal capable of forming a silicide is deposited and heat treatment is performed, whereby the gate 105, the source region 108, the drain region 107, a part of the transfer gate 102, and the detection capacitor portion 103. Silicide 109 is formed in a part of the film. For example, cobalt (Co), titanium (Ti), nickel (Ni), and the like are generally used as the metal capable of forming silicide.

  In general, a silicide formation technique is used to reduce source, drain or contact resistance in a MOS integrated circuit. However, there is a problem in that substrate leakage increases due to distortion caused by the difference in thermal expansion coefficient between the silicide and the substrate.

Also in the conventional solid-state imaging device 100, dislocation occurs due to the difference in thermal expansion coefficient between the silicide 109 such as cobalt silicide (CoSi ₂ ) and titanium silicide (TiSi ₂ ) and the substrate 106 made of silicon. Dark current is generated by the defect. For example, the difference in thermal expansion coefficient between cobalt silicide (CoSi ₂ ) that is silicide 109 and substrate 106 that is silicon is about 1.2%. Defects caused by this cause junction leakage. When the junction leak occurs, the noise component with respect to the accumulated charge in the photoelectric conversion region 101 is increased, and the S / N is deteriorated, so that the image quality is deteriorated (see, for example, Non-Patent Document 1). Note that the cause of the junction leakage is specifically the silicide 109 formed on the source region 107, the drain region 108, and the detection capacitor 103. In particular, junction leakage due to the detection capacitor 103 becomes a problem.

The solid-state image sensor is disclosed in, for example, Patent Document 1 below.
JP-A-11-312731 IEEE Transactions on Electron Devices 1999, vol. 43, p. 1989-1993

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a solid-state imaging device that can hardly cause junction leakage despite the formation of silicide and can improve S / N, a manufacturing method thereof, and a camera using the same. The purpose is to do.

  In the first solid-state imaging device of the present invention, a voltage is applied to a photoelectric conversion region formed in a substrate, a transfer gate for transferring charges converted in the photoelectric conversion region, and the transfer gate. A solid-state imaging device comprising: a detection capacitor for storing the charge transferred from the photoelectric conversion region; and a MOS transistor for signal processing the charge stored in the detection capacitor. Silicide is formed only on the transfer gate and the gate of the MOS transistor.

  The second solid-state imaging device of the present invention includes a photoelectric conversion region formed in a substrate, a transfer gate for transferring charges converted in the photoelectric conversion region, and a voltage applied to the transfer gate. A solid-state imaging device comprising: a detection capacitor unit that accumulates charges transferred from the photoelectric conversion region by being applied; and a MOS transistor that performs signal processing on the charges accumulated in the detection capacitor unit, wherein Silicide is formed at the contact portion on the transfer gate and the detection capacitor portion, which is a place to be formed, and the silicide formed on the contact portion is formed at a place other than on the transfer gate and the detection capacitor portion. Thicker than the silicide formed.

  The third solid-state imaging device of the present invention has a photoelectric conversion region formed in a substrate, a transfer gate for transferring charges converted in the photoelectric conversion region, and a voltage applied to the transfer gate. A solid-state imaging device comprising: a detection capacitor that accumulates charges transferred from the photoelectric conversion region when applied; and a MOS transistor that performs signal processing on the charges accumulated in the detection capacitor, wherein the detection The capacitor portion is doped with nitrogen, and silicide is formed on the detection capacitor portion.

  The camera of the present invention uses any one of the first to third solid-state imaging devices.

  Further, the first manufacturing method of the solid-state imaging device according to the present invention includes a photoelectric conversion region that converts light into electric charge, a detection capacitor unit that accumulates the charge converted in the photoelectric conversion region, and a detection capacitor unit. A method of manufacturing a solid-state imaging device including a MOS transistor for signal processing of charge, wherein the photoelectric conversion region and the detection capacitor unit are provided in a substrate, and a transfer gate is provided above the photoelectric conversion region and the detection capacitor unit. After forming the source region and drain region of the MOS transistor in the substrate around the photoelectric conversion region and forming the gate of the MOS transistor above the substrate, an insulating deposition film is formed so as to cover the entire surface. The insulating deposited film is removed so that the surfaces of the gate of the MOS transistor and the transfer gate are exposed, and the gate is transferred onto the gate and the transfer gate. To form a side.

  Further, the second manufacturing method of the solid-state imaging device of the present invention includes a photoelectric conversion region that converts light into electric charge, a detection capacitor unit that accumulates the charge converted in the photoelectric conversion region, and a detection capacitor unit. A method of manufacturing a solid-state imaging device including a MOS transistor for signal processing of charge, wherein the photoelectric conversion region and the detection capacitor unit are provided in a substrate, and a transfer gate is provided above the photoelectric conversion region and the detection capacitor unit. After forming the source region and drain region of the MOS transistor in the substrate around the photoelectric conversion region and forming the gate of the MOS transistor above the substrate, an insulating deposition film is formed so as to cover the entire surface. At least the insulating deposited film on the contact portion where the contact is formed is removed, the first silicide is formed, and the insulating deposited film is removed. At least a portion of the insulating deposited film is removed, and forming a second silicide.

  A third method for manufacturing a solid-state imaging device according to the present invention includes: a photoelectric conversion region that converts light into charges; a detection capacitor unit that accumulates charges converted in the photoelectric conversion region; A method of manufacturing a solid-state imaging device including a MOS transistor for signal processing of charge, wherein the photoelectric conversion region and the detection capacitor unit are provided in a substrate, and a transfer gate is provided above the photoelectric conversion region and the detection capacitor unit. After forming the source region and drain region of the MOS transistor in the substrate around the photoelectric conversion region, and forming the gate of the MOS transistor above the substrate, the detection capacitor portion is doped with nitrogen, Silicide is formed in the detection capacitor portion.

  According to the present invention, it is possible to provide a solid-state imaging device that can hardly cause junction leakage even though silicide is formed and can improve S / N, a manufacturing method thereof, and a camera using the same. it can.

  Since the silicide is formed only on the transfer gate formed above the substrate and the gate of the MOS transistor in the first solid-state imaging device of the present invention, junction leakage hardly occurs in the substrate. It is possible to improve.

  In the second solid-state imaging device of the present invention, silicide is formed in the contact portion, and the silicide formed in the contact portion is thicker than the silicide formed in other portions, so that the contact resistance of the contact is large. Never become.

  Further, in the third solid-state imaging device of the present invention, since the detection capacitor portion is doped with nitrogen and silicide is formed, junction leakage hardly occurs in the substrate, so that the S / N is improved. Is possible.

  The solid-state imaging device according to any one of the first to third aspects of the present invention preferably further includes a polysilicon wiring, and silicide is formed in the wiring. Thereby, the resistance of the wiring is reduced.

  In addition, since the camera of the present invention uses any one of the first to third solid-state imaging devices, high image quality can be realized.

  Further, in the first manufacturing method of the solid-state imaging device of the present invention, silicide is formed on the gate and the transfer gate, so that a junction leakage is hardly generated on the substrate, and a solid-state imaging device with improved S / N is simplified. It can be manufactured by the method.

  In the first manufacturing method, the source region, the drain region, and the detection capacitor portion may not be exposed when the insulating deposition film is removed. As a result, it is possible to manufacture a solid-state imaging device in which junction leakage hardly occurs in the substrate and the S / N is improved by a simple method.

  In the first manufacturing method, when the insulating deposition film is removed, the detection capacitor portion and the photoelectric conversion region may not be exposed. As a result, it is possible to manufacture a solid-state imaging device in which junction leakage hardly occurs in the substrate and the S / N is improved by a simple method.

  In the second manufacturing method of the solid-state imaging device of the present invention, the thicknesses of the first silicide and the second silicide can be made different. Therefore, it is possible to manufacture a solid-state imaging device having a desired thickness of silicide such as a thin first silicide in the contact portion and a thin second silicide in a portion where leakage is desired to be reduced.

  Further, in the third manufacturing method of the solid-state imaging device according to the present invention, only the detection capacitor portion is doped with nitrogen and silicide is formed in the detection capacitor portion. Therefore, junction leakage hardly occurs in the substrate and S / N is improved. The solid-state imaging device thus manufactured can be manufactured by a simple method.

  Preferably, in the first to third manufacturing methods, the solid-state imaging device includes a polysilicon wiring, and silicide is formed on the wiring. Thereby, a solid-state image sensor with low wiring resistance can be manufactured.

  Hereinafter, more specific embodiments of the present invention will be described.

(Embodiment 1)
A solid-state imaging device and a manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the solid-state imaging device according to the first embodiment. 2A to 2E are cross-sectional process diagrams for illustrating the method for manufacturing the solid-state imaging device according to the first embodiment.

  As shown in FIG. 1, the solid-state imaging device 20 according to Embodiment 1 is formed between a light detection unit 12, a transistor unit 13, and a light detection unit 12 and a transistor unit 13 which is a MOS transistor. And an element isolation region 11 for isolation. The element isolation region 11 may be formed by, for example, trench isolation (STI: Shallow Trench Isolation), silicon oxide local method (LOCOS), ion implantation, or the like.

  The light detection unit 12 includes a photoelectric conversion region 1 that converts light into electric charge, a transfer gate 2 that transfers a charge in the photoelectric conversion region 1 to the detection capacitor unit 3 by applying a voltage, and a photoelectric conversion region 1. And a detection capacitor unit 3 for accumulating the charges transferred from. The transistor unit 13 includes a gate 5, a drain region 7, and a source region 8.

  The photoelectric conversion region 1 is, for example, a photodiode. The element isolation region 11, the photoelectric conversion region 1, the detection capacitor unit 3, the drain region 7 and the source region 8 are formed in the substrate 6 made of silicon, and the transfer gate 2 and the gate 5 are formed through the oxide film 15. 6 is formed above.

  Further, a silicide 9 is formed on the transfer gate 2 of the light detection unit 12 and the gate 5 of the transistor unit 13. Thus, the silicide 9 is formed only on the transfer gate 2 and the gate 5. As a result, the silicide 9 and the substrate 6 do not come into contact with each other, and junction leakage hardly occurs. Therefore, S / N is improved.

  The operation of such a solid-state image sensor 20 will be described. When light enters the photoelectric conversion region 1, charges are generated in the photoelectric conversion region 1. In this state, a voltage is applied to the transfer gate 2 to turn it “ON”, whereby the charge in the photoelectric conversion region 1 is transferred to the detection capacitor unit 3 and the potential of the detection capacitor unit 3 changes. The change in potential of the detection capacitor unit 3 is transmitted to the gate 5 of the transistor unit 13 to detect an optical signal and perform signal processing.

  Next, the manufacturing method of the solid-state imaging device according to the first embodiment will be described with reference to FIGS. As shown in FIG. 2A, the photodetecting portion 12 and the transistor portion 13 are formed on the substrate 6, the oxide film 15 is formed on the entire surface, and the transfer gate 2 and the gate 5 are further formed. This may be formed by a conventional method. Next, as shown in FIG. 2B, an insulating deposition film 4 is deposited on the entire surface. Next, as shown in FIG. 2C, the insulating deposited film 4 is removed and planarized to expose the surfaces of the transfer gate 2 and the gate 5. It is desirable that the source region 8, the drain region 7, and the detection capacitor portion 3 are not exposed when the insulating deposition film 4 is removed. Similarly, it is desirable that the detection capacitor 3 and the photoelectric conversion region 1 are not exposed when the insulating deposition film 4 is removed.

  Next, after ion implantation is performed on the entire surface, as shown in FIG. 2D, a metal 19 capable of forming a silicide is deposited on the entire surface. As the metal 19 capable of forming a silicide, for example, cobalt (Co), titanium (Ti), nickel (Ni) and the like are generally used. Next, heat treatment is performed to change the transfer gate 2 and the metal 19 on the gate 5 made of polysilicon into silicide 9. The ion implantation is performed to make the surface amorphous so that the reaction (silicidation) between the metal 19 capable of forming silicide and the transfer gate 2 and the gate 5 easily occurs. Thereafter, the insulating deposition film 4 and the unreacted metal 19 thereon are removed by wet processing, thereby forming a silicide 9 only on the transfer gate 2 and the gate 5 as shown in FIG. Thus, no silicide 9 is formed in the source region 7 and the drain region 8 of the detection capacitor unit 3 and the transistor unit 13. For this reason, junction leakage hardly occurs between the silicide 9 and the silicon substrate 6.

  For example, after the planarization shown in FIG. 2C, if the silicide 9 is removed after further removing the insulating deposition film 4 on the transistor unit 13, only on the photoelectric conversion region 1 and the detection capacitor unit 3. A configuration in which no silicide is formed is also possible.

(Embodiment 2)
A solid-state imaging device and a manufacturing method thereof according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing the configuration of the solid-state imaging device according to the second embodiment. FIG. 4A to FIG. 4F are cross-sectional process diagrams for illustrating the method for manufacturing the solid-state imaging device according to the second embodiment.

  The solid-state imaging device 30 according to the second embodiment has not only silicides 9a and 9b formed on the transfer gate 2 and the gate 5 as in the solid-state imaging device according to the first embodiment, but also on the drain region 7. The silicides 9 a and 9 b are also formed on the source region 8, a part on the transfer gate 2 and a part on the detection capacitor 3. 3 and 4, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 3, in the solid-state imaging device 30 according to the second embodiment, the silicide 9 b is formed on the gate electrode 5, the source region 7, and the drain region 8 of the transistor unit 13. A silicide 9 a is formed on a part of the detection capacitor 3 of the light detection unit 12, and an oxide film 15 is formed on the rest. Further, a silicide 9a is formed on a part of the transfer gate 2 of the light detection unit 12, and the insulating deposition film 4 is formed on the rest. Further, sidewalls 17 are formed on the transfer gate 2 and the gate 5. Note that a contact (not shown) is formed on a part of the transfer gate 2 and the detection capacitor portion 3, and this portion is referred to as a contact portion 16. Further, since the silicide 9a is formed on a part of the detection capacitor unit 3, junction leakage can be reduced as compared with the case where it is formed on the entire surface of the detection capacitor unit 3. Further, the silicide 9a is formed on the contact portion 16 to be thicker than other regions. The thickness of the silicide 9a is preferably 30 nm or more, and the thickness of the silicide 9b in other regions is preferably 5 to 30 nm.

  A contact can be stably formed in the contact portion 16 by forming the silicide 9a thicker than other regions. The reason will be described below. In the step of forming a contact, first, an oxide film or the like is deposited with the silicide 9a formed on the contact portion 16, an opening is formed by dry etching, and then a metal such as W (tungsten) is embedded to form the contact. It is to form. At this time, if the silicide 9a is too thin, the silicide 9a is penetrated by etching, and the contact resistance of the contact increases. Therefore, the penetration can be prevented by increasing the thickness of the silicide 9a. The thickness of the silicide 9a in the contact portion 16 is preferably 30 nm or more.

  As the silicides 9a and 9b are thinner, the stress with the substrate 6 is reduced and the leakage current is reduced. However, the resistance increases below a certain film thickness. As in the second embodiment, the formation of silicides 9b and 9a in the source region 7, the drain region 8, and the detection capacitor 3 causes junction leakage. Therefore, the silicide 9b in the source region 7 and the drain region 8 may be thinned in order to reduce junction leakage. Further, the thickness of the silicide 9a of the contact portion 16 may be determined so as to satisfy the optimum conditions in consideration of both contact resistance and junction leakage.

  Due to the above configuration, in the solid-state imaging device 30, the silicide 9a of the contact portion 16 is thickened. Thereby, the contact resistance of the contact does not increase. Further, since the silicide 9b in the source region 7 and the drain region 8 is thin, junction leakage with the substrate 6 hardly occurs, so that the S / N is improved. Further, since the operation of the solid-state imaging device 30 of the second embodiment is the same as that of the solid-state imaging device 20 of the first embodiment, description thereof is omitted.

  Next, a method for manufacturing the solid-state imaging device according to the second embodiment will be described with reference to FIGS. 4 (a) to 4 (f). As shown in FIG. 4A, the photodetection section 12 and the transistor section 13 are formed on the substrate 6 and the transfer gate 2 and the gate 5 are formed. This may be formed by a conventional method. Next, as shown in FIG. 4B, an insulating deposition film 4 is deposited on the entire surface. Next, as shown in FIG. 4C, the insulating deposited film 4 in the contact portion 16 is removed, and further, the oxide film 15 formed at the place where the silicide 9 is formed on the detection capacitor portion 3 is removed. For the removal, for example, dry etching is used, and at this time, the sidewall 17 of the transfer gate 2 is formed. Next, a metal capable of forming a silicide is deposited on the contact portion 16, heat treatment is performed, and unreacted metal is removed, thereby forming a silicide 9a as shown in FIG. The silicide 9a formed at this time is formed thicker than the silicide 9b formed in the subsequent steps as described above.

  Next, as shown in FIG. 4E, the insulating deposition film 4 on the element isolation region 11 and the transistor portion 13 is removed, and the oxide film 15 on the element isolation region 11, the drain region 7 and the source region 8 is further removed. Remove. For the removal, for example, dry etching is used, and at this time, the sidewall 17 of the gate 5 is formed. Next, after depositing a metal capable of forming a silicide, heat treatment is performed to remove the unreacted metal, thereby forming a silicide 9b on the gate 5, the drain region 7 and the source region 8 as shown in FIG. Form.

  Thus, since silicide 9a and 9b are formed in a different process, they can be formed so that each thickness differs. Thereby, silicides 9a and 9b having different thicknesses can be formed in accordance with the formation locations. For example, the silicide 9b can be thinned only at a portion where leakage current is desired to be reduced, or the silicide 9a can be thickened at a portion where a contact is to be formed.

(Embodiment 3)
A solid-state imaging device and a manufacturing method thereof according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 5 is a cross-sectional view showing the configuration of the solid-state imaging device according to the third embodiment. 6A to 6E are cross-sectional process diagrams illustrating a method for manufacturing the solid-state imaging element according to the third embodiment.

The solid-state imaging device 40 according to the third embodiment has a configuration in which all silicides are the same in the solid-state imaging device of the second embodiment, and nitrogen (N ₂ ) is injected into the detection capacitor unit 3. 5 and 6, members having the same functions as those described in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 5, in the solid-state imaging device 40 of the third embodiment, the silicide 9 is formed on the gate 5, the drain region 7, the source region 8 and the contact portion 16. That is, it is formed on the substrate 6 and also on the gate 5 and the transfer gate 2 which are polysilicon films. Further, nitrogen (N ₂ ) is injected into the detection capacitor unit 3 where leakage should be reduced.

  Because of such a configuration, even if the silicide 9 is not formed or the thickness of the silicide 9 is not reduced, junction leakage between the silicide 9 and the substrate 6 in the detection capacitor portion 3 is unlikely to occur. Therefore, S / N is improved. Further, since the operation of the solid-state imaging device 40 of the third embodiment is the same as that of the solid-state imaging device 20 of the first embodiment, description thereof is omitted.

  Next, a method for manufacturing the solid-state imaging element according to Embodiment 3 will be described with reference to FIGS. 6 (a) to 6 (e). As shown in FIG. 6A, the photodetecting portion 12 and the transistor portion 13 are formed on the substrate 6 and the transfer gate 2 and the gate 5 are formed. This may be formed by a conventional method. Next, as shown in FIG. 6B, an insulating deposition film 4 is deposited on the entire surface. Next, as shown in FIG. 6C, the insulating deposition film 4 in the contact portion 16 is removed, and further, the oxide film 15 formed at the place where the silicide 9 on the detection capacitor portion 3 is formed is removed. For the removal, for example, dry etching is used, and at this time, the sidewall 17 of the transfer gate 2 is formed. In addition, ion implantation is performed on a region where silicide is to be formed, and amorphousization is performed. Further, nitrogen is doped into the detection capacitor portion 3 which is a portion where leakage is to be reduced.

  Next, as illustrated in FIG. 6D, the insulating deposition film 4 on the element isolation region 11 and the transistor portion 13 is removed, and the oxide film 15 on the element isolation region 11, the drain region 7, and the source region 8 is further removed. Remove. For the removal, for example, dry etching is used, and at this time, the sidewall 17 of the gate 5 is formed. Next, after depositing a metal capable of forming a silicide, heat treatment is performed to remove the unreacted metal, whereby the gate 5, the drain region 7, the source region 8, and the contact portion 16 are removed as shown in FIG. Silicide 9 can be formed thereon.

  By such a manufacturing method, a Si—N bond between nitrogen and silicon is formed on the substrate 6 around the detection capacitor portion 3 which is a nitrogen-doped portion. Thereby, the penetration of the silicide 9 in the direction of the substrate 6 (spike) is suppressed, and the solid-state imaging device 40 of the third embodiment is less likely to leak and the S / N is improved.

  As described above, in the solid-state imaging devices according to the first to third embodiments, even if silicide is formed, junction leakage is reduced and dark current is also reduced. Thereby, the S / N of the photoelectric conversion region can be improved.

  In the solid-state imaging device according to the first to third embodiments, silicide may be formed in the wiring region formed of polysilicon. Thereby, the wiring resistance can be lowered.

  Moreover, the transistor part which is a MOS transistor of the solid-state imaging device according to the first to third embodiments may be either P-type or N-type.

  Moreover, the manufacturing method of the solid-state imaging device according to Embodiments 1 to 3 is suitable for mass production because the solid-state imaging device can be manufactured by a simple processing process.

  The solid-state imaging device according to the first to third embodiments of the present invention described above may be used for a camera, and is preferably used for, for example, a digital still camera or a mobile phone camera. Thereby, the image quality can be greatly improved, and a high-performance camera can be realized.

  Note that the materials and structures specifically shown in the embodiments are merely examples, and the present invention is not limited to these specific examples.

  The solid-state imaging device of the present invention is advantageous in that it is difficult to cause junction leakage despite the formation of silicide and has an advantage of improving S / N.

Sectional drawing which shows the structure of the solid-state image sensor which concerns on Embodiment 1. FIG. Sectional process drawing for illustrating the method for manufacturing the solid-state imaging device according to the first embodiment Sectional drawing which shows the structure of the solid-state image sensor which concerns on Embodiment 2. FIG. Sectional process drawing for illustrating a method for manufacturing a solid-state imaging device according to the second embodiment Sectional drawing which shows the structure of the solid-state image sensor which concerns on Embodiment 3. FIG. Sectional process drawing for illustrating a method for manufacturing a solid-state imaging device according to Embodiment 3 Sectional drawing which shows the structure of the conventional solid-state image sensor Process diagram of conventional solid-state imaging device manufacturing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoelectric conversion area | region 2 Transfer gate 3 Detection capacity | capacitance part 4 Insulation deposit film 5 Gate 6 Substrate 7 Drain area 8 Source area 9, 9a, 9b Silicide 11 Element isolation area 12 Photodetection part 13 Transistor part 15 Oxide film 16 Contact part 17 Sidewall 19 Metal 20, 30, 40 Solid-state imaging device 100 Solid-state imaging device 101 Photoelectric conversion region 102 Transfer gate 103 Detection capacitance unit 105 Gate 106 Substrate 107 Drain region 108 Source region 109 Silicide 111 Element isolation region 112 Photodetection unit 113 Transistor Part 115 Oxide film 117 Side wall

Claims (11)

Transferred from the photoelectric conversion region by applying a voltage to the photoelectric conversion region formed in the substrate, a transfer gate for transferring the charge converted in the photoelectric conversion region, and the transfer gate A solid-state imaging device comprising a detection capacitor unit for accumulating charge and a MOS transistor for signal processing the charge accumulated in the detection capacitor unit,
A solid-state imaging device, wherein silicide is formed only on the transfer gate and the gate of the MOS transistor formed above the substrate. A photoelectric conversion region formed in the substrate, a transfer gate for transferring charges converted in the photoelectric conversion region, and a charge transferred from the photoelectric conversion region by applying a voltage to the transfer gate A solid-state imaging device comprising a detection capacitor unit for storing the charge and a MOS transistor for signal processing the charge accumulated in the detection capacitor unit,
Silicide is formed at the contact portion on the transfer gate and the detection capacitor portion, which is a place where a contact is formed, and the silicide formed on the contact portion is located at a place other than on the transfer gate and the detection capacitor portion. A solid-state imaging device characterized in that it is thicker than the silicide formed on the substrate. Transferred from the photoelectric conversion region by applying a voltage to the photoelectric conversion region formed in the substrate, a transfer gate for transferring the charge converted in the photoelectric conversion region, and the transfer gate A solid-state imaging device comprising a detection capacitor unit for accumulating charge and a MOS transistor for signal processing the charge accumulated in the detection capacitor unit,
A solid-state imaging device, wherein the detection capacitor portion is doped with nitrogen, and silicide is formed on the detection capacitor portion.   The solid-state imaging device according to claim 1, further comprising polysilicon wiring, wherein silicide is formed in the wiring.   The camera using the solid-state image sensor in any one of Claims 1-4. Manufacture of a solid-state imaging device including a photoelectric conversion region that converts light into electric charge, a detection capacitor unit that accumulates the charge converted in the photoelectric conversion region, and a MOS transistor that performs signal processing on the charge from the detection capacitor unit A method,
The photoelectric conversion region and the detection capacitor in the substrate, the transfer gate above the photoelectric conversion region and the detection capacitor, the source region and the drain of the MOS transistor in the substrate around the photoelectric conversion region After forming the gate of the MOS transistor above the substrate,
An insulating deposited film is formed to cover the entire surface,
Removing the insulating deposited film so that the surfaces of the gate of the MOS transistor and the transfer gate are exposed;
A method of manufacturing a solid-state imaging device, wherein silicide is formed on the gate and the transfer gate.   The method of manufacturing a solid-state imaging device according to claim 6, wherein the source region, the drain region, and the detection capacitor portion are not exposed when the insulating deposition film is removed.   The method for manufacturing a solid-state imaging element according to claim 6, wherein the detection capacitor portion and the photoelectric conversion region are not exposed when the insulating deposition film is removed. Manufacture of a solid-state imaging device including a photoelectric conversion region that converts light into electric charge, a detection capacitor unit that accumulates the charge converted in the photoelectric conversion region, and a MOS transistor that performs signal processing on the charge from the detection capacitor unit A method,
The photoelectric conversion region and the detection capacitor in the substrate, the transfer gate above the photoelectric conversion region and the detection capacitor, the source region and the drain of the MOS transistor in the substrate around the photoelectric conversion region After forming the gate of the MOS transistor above the substrate,
An insulating deposited film is formed to cover the entire surface,
Removing at least the insulating deposited film on the contact portion where the contact is to be formed to form a first silicide;
A method of manufacturing a solid-state imaging device, wherein the second silicide is formed by removing at least a part of the insulating deposited film other than the portion where the insulating deposited film is removed. Manufacture of a solid-state imaging device including a photoelectric conversion region that converts light into electric charge, a detection capacitor unit that accumulates the charge converted in the photoelectric conversion region, and a MOS transistor that performs signal processing on the charge from the detection capacitor unit A method,
The photoelectric conversion region and the detection capacitor in the substrate, the transfer gate above the photoelectric conversion region and the detection capacitor, the source region and the drain of the MOS transistor in the substrate around the photoelectric conversion region After forming the gate of the MOS transistor above the substrate,
Nitrogen doping is performed on the detection capacitor,
A method of manufacturing a solid-state imaging device, wherein silicide is formed on the detection capacitor portion. The solid-state imaging device includes polysilicon wiring,
The method for manufacturing a solid-state imaging device according to any one of claims 6 to 10, wherein silicide is formed on the wiring.

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