Solid-state imaging device with channel stop region with multiple impurity regions in depth direction and method for manufacturing the same

Abstract

Channel stop sections formed by multiple times of impurity ion implanting processes. Four-layer impurity regions are formed across the depth of a semiconductor substrate (across the depth of the bulk), so that a P-type impurity region is formed deep in the semiconductor substrate; thus, incorrect movement of electric charges is prevented. Other four-layer impurity regions of another channel stop section are decreased in width step by step across the depth of the substrate, so that the reduction of a charge storage region of a light receiving section due to the dispersion of P-type impurity in the channel stop section is prevented in the depth of the substrate.

Claims

1. An imaging device, comprising: a semiconductor substrate having a first side and a second side opposite to the first side; a first photoelectric conversion section and a second photoelectric conversion section disposed in the semiconductor substrate; a transfer electrode adjacent to the first side of the semiconductor substrate; a channel stop section disposed between the first photoelectric conversion section and the second photoelectric conversion section; wherein, the first and second photoelectric conversion sections each include an N-type region, the channel stop section includes a P-type region, and a cross-section shape of the channel stop section is tapered in a direction from the first side to the second side.

2. The imaging device according to claim 1, wherein the channel stop section has a plurality of adjoining impurity regions including at least a first impurity region and a second impurity region associated with the first impurity region disposed along the direction from the first side to the second side.

3. The imaging device according to claim 2, further comprising a third impurity region associated with the second impurity region along the direction from the first side to the second side, wherein when viewed in the direction from the first side to the second side, a cross-sectional area of the third impurity region is smaller than a cross-sectional area of the second impurity region.

4. The imaging device according to claim 2, wherein each of the impurity regions, when viewed in a direction of increasing depth of the semiconductor substrate, has a generally uniform cross-sectional area that is different for at least two of the impurity regions.

5. The imaging device according to claim 2, wherein each of the impurity regions, when viewed in a direction of increasing depth of the semiconductor substrate, has a generally uniform cross-sectional area that is different for at least two of the impurity regions.

6. The imaging device according to claim 4, wherein, for each of the impurity regions in the direction of increasing depth of the semiconductor substrate, the generally uniform cross-sectional area is less than that of a preceding adjoining impurity region.

7. The imaging device according to claim 3, wherein each of the impurity regions, when viewed in the direction from the first side to the second side, has a generally uniform cross-sectional area and wherein, for each of the impurity regions in the direction from the first side to the second side, the generally uniform cross-sectional area is less than that of a preceding adjoining impurity region.

8. The imaging device according to claim 2, wherein each of the impurity regions, when viewed in a direction of increasing depth of the semiconductor substrate, has a generally uniform cross-sectional area equal to the generally uniform cross-sectional area of each other impurity region of the plurality of adjoining impurity regions.

9. The imaging device according to claim 2, further comprising a third impurity region associated with the second impurity region along the direction from the first side to the second side, wherein each of the impurity regions, when viewed in the direction from the first side to the second side, has a generally uniform cross-sectional area equal to the generally uniform cross-sectional area of each other impurity region of the plurality of adjoining impurity regions.

10. The imaging device according to claim 2, wherein each of the impurity regions has an ion concentration different from the ion concentration of at least one other impurity region.

11. The imaging device according to claim 3, wherein each of the impurity regions has an ion concentration different from the ion concentration of at least one other impurity region.

12. The imaging device according to claim 1, wherein the imaging device is a CCD imaging device.

13. The imaging device according to claim 1, wherein the imaging device is a CMOS imaging device.

14. An imaging device comprising: a semiconductor substrate having a first side and a second side opposite to the first side; a first photoelectric conversion section and a second photoelectric conversion section disposed in the semiconductor substrate; a transfer electrode adjacent to the first side of the semiconductor substrate; a channel stop section disposed between the first photoelectric conversion section and the second photoelectric conversion section; and an overflow barrier disposed in the semiconductor substrate; wherein, the channel stop section is in contact with the overflow barrier, the first and second photoelectric conversion sections each include an N-type region, the channel stop section includes a P-type region, and a cross-section shape of the channel stop section is tapered in a direction from the first side to the second side.

15. The imaging device according to claim 14, wherein the channel stop section has a plurality of adjoining impurity regions including at least a first impurity region and a second impurity region associated with the first impurity region disposed along the direction from the first side to the second side.

16. The imaging device according to claim 15, further comprising a third impurity region associated with the second impurity region along the direction from the first side to the second side, wherein the cross-sectional area of the third impurity region is smaller than a cross-sectional area of the second impurity region.

17. The imaging device according to claim 15, wherein each of the impurity regions, when viewed in a direction of increasing depth of the semiconductor substrate, has a generally uniform cross-sectional area that is different for at least two of the impurity regions.

18. The imaging device according to claim 15, wherein each of the impurity regions has an ion concentration different from the ion concentration of at least one other impurity region.

19. The imaging device according to claim 14, wherein the imaging device is a CCD imaging device.

20. The imaging device according to claim 14, wherein the imaging device is a CMOS imaging device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a sectional view of a solid-state imaging device along the vertical direction according to an embodiment of the present invention;

(2) FIG. 2 is a sectional view of the solid-state imaging device along the horizontal direction according to the embodiment of the present invention;

(3) FIG. 3 is a sectional view of a solid-state imaging device along the vertical direction according to another embodiment of the present invention;

(4) FIG. 4 is a sectional view of a solid-state imaging device along the vertical direction according to yet another embodiment of the present invention;

(5) FIG. 5 is a sectional view of a solid-state imaging device along the vertical direction according to still another embodiment of the present invention;

(6) FIG. 6 is a plan view of the arrangement of a CCD solid-state imaging device;

(7) FIG. 7 is a sectional view of a related-art solid-state imaging device along the vertical direction; and

(8) FIG. 8 is a sectional view of the related-art solid-state imaging device along the horizontal direction.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(9) Embodiments of a solid-state imaging device and a method for manufacturing the same according to the present invention will be specifically described hereinafter.

(10) FIGS. 1 and 2 are sectional views of a solid-state imaging device manufactured by the method according to an embodiment, FIG. 1 showing an embodiment of a channel stop section provided between photosensors along the vertical transfer direction, and FIG. 2 showing an embodiment of a channel stop section provided between the photosensors along the horizontal transfer direction. The entire structure of the solid-state imaging device is the same as that of the related art shown in FIG. 6, wherein FIG. 1 corresponds to the section taken along line A-A of FIG. 6 and FIG. 2 corresponds to the section taken along line B-B of FIG. 6.

(11) Referring first to FIG. 1, a photodiode region constituting a light receiving section 10 of each photosensor includes a P+ type impurity region (hole storage region) 10A formed in the outer layer of a substrate 100 and an N-type impurity region (electron storage region) 10B formed under the P+-type impurity region 10A. The photodiode region photoelectrically converts light that is incident from above, absorbs holes into the P+ type impurity region 10A, and stores electrons in the N-type impurity region 10B, a lower depletion layer and so on.

(12) The photoelectric conversion in the light receiving section 10 is mainly performed in a depletion region between the N-type impurity region 10B and the P+ type impurity region 10A and in a depletion region between the N-type impurity region 10B and a lower P-type impurity region (not shown).

(13) A channel stop section 20 formed of a multilayer P-type impurity region is provided in the vicinity of opposite

(14) sides of the photodiode region along the vertical transfer direction.

(15) The channel stop section 20 is formed by multiple times of impurity implanting processes by which four impurity regions 20A, 20B, 20C, and 20D are formed across the depth of the substrate 100 (along the depth of the bulk) to form a P-type region deep in the substrate 100, thereby preventing leakage of electric charges.

(16) Referring to FIG. 2, the photodiode region of each photosensor includes the P+ type impurity region 10A and the N-type impurity region 10B, as that shown in FIG. 1.

(17) A CCD vertical transfer section 40 is formed on the side of the photodiode region through a readout gate.

(18) The CCD vertical transfer section 40 is formed of an upper N-type impurity region 40A and a lower P-type impurity region 40B.

(19) A channel stop section 50 that is a multilayer P-type impurity region is provided between the CCD vertical transfer section 40 and the photodiode region of the adjacent photosensor train.

(20) The channel stop section 50 is formed by multiple times of impurity implanting processes by which four impurity regions 50A, 50B, 50C, and 50D are formed across the depth of the substrate 100 (along the depth of the bulk) to form a

(21) P-type region deep in the substrate 100, thereby preventing leakage of electric charges.

(22) In FIGS. 1 and 2, transfer electrodes 60 of the CCD vertical transfer sections 40 and so on are provided on the top of the substrate 100 through a gate insulating film (not shown). However, their detailed description will be omitted here because they are not directly related to the present invention.

(23) When the channel stop sections 20 and 50 are formed in the above-described solid-state imaging device, an ion implantation region is set using a specified mask and multiple times of ion implanting processes are performed with multiple ion implanting energies and impurity concentrations, so that the multilayer impurity regions 20A, 20B, 20C, and 20D and the impurity regions 50A, 50B, 50C, and 50D are formed.

(24) Thus, the channel stop sections 20 and 50 can be formed deep into the substrate 100, thereby preventing the leakage of signal charges between the devices to reduce color mixture.

(25) Since the concentration of impurity in each ion implanting process can be set as appropriate, the concentration of impurity near the surface of the substrate 100 that is formed with low implanting energy can be sufficiently ensured by making the ion concentration of impurity in an ion implanting process with relatively high implanting energy higher than that in an ion implanting process with relatively low implanting energy, so that a smear phenomenon can be prevented.

(26) When the solid-state imaging device is formed, ions are continuously implanted into the substrate 100 to form the photodiode region (light receiving section 10), the CCD vertical transfer section 40, and the respective impurity regions of the channel stop sections 20 and 50; the order thereof is not particularly limited.

(27) Also the order of the multiple times of ion implanting processes for forming the channel stop sections 20 and 50 is not particularly limited.

(28) The mask for ion implantation includes various types in addition to a general resist mask; therefore, it is not particularly limited.

(29) A specific energy and the concentration of impurity in each ion implanting process can be set as appropriate and are not particularly limited.

(30) In the embodiment, the vertical channel stop section 20 and the horizontal channel stop section 50 are separately formed so as to be optimized for the respective required characteristics, with individual ion implanting energy and impurity concentration. In FIGS. 1 and 2, although both the channel stop sections 20 and 50 have four-layer structure (or four-step ion implantation), they are not limited to that and may have a structure other than the four-layer (four-step) structure. The vertical channel stop section 20 and the horizontal channel stop section 50 may not necessarily have the same number of layers.

(31) The impurity concentration may not be varied at all the layers but may be varied at part of the layers.

(32) In the above embodiment, the ion implanting processes for forming the channel stop sections 20 and 50 are carried out with multiple energies and concentrations. However, the ion implantation region is varied in each ion implanting process by changing a mask in each ion implanting process, so that the width across the channel of the respective impurity regions of the channel stop sections 20 and 50 may be varied.

(33) FIG. 3 is a sectional view of an example of the channel stop section along the vertical transfer direction. Since components other than a channel stop section 70 are the same as those of FIG. 1, they are given the same numerals and there description will be omitted.

(34) As shown in the drawing, the channel stop section 70 includes four-layer impurity regions 70A, 70B, 70C, and 70D. When the ion implanting area in an ion implanting process with relatively high implanting energy is made smaller than that in an ion implanting process with relatively low implanting energy, the reduction of the charge storage region of the light receiving section 10 in the deep part of the substrate 100 by the dispersion of P-type impurity of the channel stop section 70 can be prevented; thus, sensitivity of the light receiving section 10 and saturation signals can be increased.

(35) The energy and the impurity concentration can be set as those in FIG. 1.

(36) Although the widths of all the layers of the channel stop section 70 may be varied, only the width of part of the layers may be varied so that only the impurity regions 70A and 70B have the equal width, as shown in FIG. 3. In this case, the layers of an equal width can be formed with a common mask.

(37) The multi-step ion implantation may also be made for the channel stop section along the horizontal transfer direction, with multiple widths.

(38) The above-described embodiments offer the following advantages:

(39) (1) Referring to FIGS. 1 to 3, when multi-step ion implantation of the channel stop section between the vertical photosensors and the channel stop section between the horizontal light receiving section and the vertical transfer section is carried out with multiple energies, a color mixing phenomenon can be prevented in which photoelectrically converted charges are mixed to the adjacent photosensors.

(40) (2) Referring to FIG. 3, when the region of ion implantation with high energy reduced, a color mixing phenomenon can be prevented without narrowing the charge storage region of the light receiving section and decreasing sensitivity and saturation signal.

(41) (3) Referring to FIGS. 1 to 3, when ions are implanted into the channel stop section with high energy, the variation of an overflow barrier at charge storage can be reduced; thus the occurrence of a knee-point (Qknee) in output characteristics can be prevented.

(42) (4) When ion implantation of the channel stop section between the horizontal light receiving section and the vertical transfer section is carried out with multiple energies, a smear phenomenon near the surface and in the bulk can be prevented.

(43) In the above-described embodiments, the positional relationship of the multi-step ion implanted impurity regions is only an example, and the thickness of the impurity regions across the depth of the substrate, the shape, and the number of layers are not limited to that. For example, as shown in FIG. 4, of the multilayer impurity region of a channel stop section 80 (three-layer impurity regions 80A, 80B, and 80C in the drawing), the middle-layer impurity region (the impurity region 80B in the drawing) may

(44) be larger in thickness and also in lateral width than the other impurity regions or vice versa.

(45) As a matter of course, the multilayer ion-implanted impurity region may have a part overlapping with the upper and lower impurity regions in the strict sense.

(46) In the above embodiments, although the multilayer ion-implanted impurity region is formed such that the bottom of the lowermost-layer region has a depth substantially equal to that of the bottom of the N-type impurity region 10B in the light receiving section 10, it is not limited to that.

(47) For example, in order to prevent color mixture in a further lower region across the depth of the substrate 100, as shown in FIG. 5, the bottom of the lowermost-layer region (an impurity region 90D in the drawing) of the multilayer ion-implanted impurity region (four-layer impurity regions 90A, 90B, 90C, and 90D in the drawing) of a channel stop section 90 may be formed deeper than the bottom of the N-type impurity region 10B.

(48) As shown in FIG. 5, an overflow barrier 92 located below the light receiving section 10 and the multilayer ion-implanted impurity region (the impurity region 90D in the drawing) may be in contact with each other.

(49) In this case, the holes stored in the overflow barrier 92 can be discharged to the surface of the substrate 100 through the multilayer ion-implanted impurity region. The multilayer ion-implanted impurity region is preferably formed such that the closer to the surface of the substrate 100 the region is, the higher the concentration of the P-type impurity is.

(50) Although a preferred form of the invention has been described in which it is applied to a CCD solid-state imaging device, it is to be understood that the invention is applied not only to the CCD solid-state imaging device but also to a CMOS solid-state imaging device.

(51) As described above, by the method for manufacturing the solid-state imaging device according to the invention, the channel stop section is formed by multiple times of impurity ion implanting processes with multiple implanting energies. Thus, a multilayer impurity region can be formed across the depth of the substrate as a channel stop section.

(52) Therefore, leakage of signal charges between the adjacent photosensors and between the photosensor and the transfer section can be effectively prevented, so that a color mixing phenomenon and so on can be effectively prevented.

(53) During the multiple times of impurity ion-implantation processes, the ion implantation is carried out for multiple implantation areas, so that the dispersion of the impurity can be reduced particularly deep in the substrate, the effects to the photoelectric conversion section can be reduced, and decreases in sensitivity and saturation signals can be effectively prevented.

(54) Furthermore, during the multiple times of impurity ion-implantation processes, the ion implantation is carried out at multiple impurity concentrations, so that the respective impurity regions of the channel stop section can be formed at optimum impurity concentrations; thus anti-smear measures on the surface of the substrate can be effectively taken.

(55) Since the solid-state imaging device according to the invention includes a channel stop section having a multilayer impurity region across the depth of the substrate, leakage of signal charges between the adjacent photosensors and between the photosensor and the transfer section can be effectively prevented; thus, a color mixing phenomenon and so on can be effectively prevented.

(56) Since the multilayer impurity region of the channel stop section has multiple areas, the dispersion of impurity particularly deep in the substrate can be prevented, the effects to the photoelectric conversion section can be reduced, and decreases in sensitivity and saturation signals can be effectively prevented.

(57) Furthermore, the multilayer impurity region of the channel stop section has an optimum impurity concentration at each layer; thus anti-smear measures on the surface of the substrate can be effectively taken.

DETAILED DESCRIPTION OF THE INVENTION

(58) Embodiments of a solid-state imaging device and a method for manufacturing the same according to the present invention will be specifically described hereinafter.

(59) FIGS. 1 and 2 are sectional views of a solid-state imaging device manufactured by the method according to an embodiment, FIG. 1 showing an embodiment of a channel stop section provided between photosensors along the vertical transfer direction, and FIG. 2 showing an embodiment of a channel stop section provided between the photosensors along the horizontal transfer direction. The entire structure of the solid-state imaging device is the same as that of the related art shown in FIG. 6, wherein FIG. 1 corresponds to the section taken along line A-A of FIG. 6 and FIG. 2 corresponds to the section taken along line B-B of FIG. 6.

(60) Referring first to FIG. 1, a photodiode region constituting a light receiving section 10 of each photosensor includes a P+ type impurity region (hole storage region) 10A formed in the outer layer of a substrate 100 and an N-type impurity region (electron storage region) 10B formed under the P+-type impurity region 10A. The photodiode region photoelectrically converts light that is incident from above, absorbs holes into the P+ type impurity region 10A, and stores electrons in the N-type impurity region 10B, a lower depletion layer and so on.

(61) The photoelectric conversion in the light receiving section 10 is mainly performed in a depletion region between the N-type impurity region 10B and the P+ type impurity region 10A and in a depletion region between the N-type impurity region 10B and a lower P-type impurity region (not shown).

(62) A channel stop section 20 formed of a multilayer P-type impurity region is provided in the vicinity of opposite

(63) sides of the photodiode region along the vertical transfer direction.

(64) The channel stop section 20 is formed by multiple times of impurity implanting processes by which four impurity regions 20A, 20B, 20C, and 20D are formed across the depth of the substrate 100 (along the depth of the bulk) to form a P-type region deep in the substrate 100, thereby preventing leakage of electric charges.

(65) Referring to FIG. 2, the photodiode region of each photosensor includes the P+ type impurity region 10A and the N-type impurity region 10B, as that shown in FIG. 1.

(66) A CCD vertical transfer section 40 is formed on the side of the photodiode region through a readout gate.

(67) The CCD vertical transfer section 40 is formed of an upper N-type impurity region 40A and a lower P-type impurity region 40B.

(68) A channel stop section 50 that is a multilayer P-type impurity region is provided between the CCD vertical transfer section 40 and the photodiode region of the adjacent photosensor train.

(69) The channel stop section 50 is formed by multiple times of impurity implanting processes by which four impurity regions 50A, 50B, 50C, and 50D are formed across the depth of the substrate 100 (along the depth of the bulk) to form a

(70) P-type region deep in the substrate 100, thereby preventing leakage of electric charges.

(71) In FIGS. 1 and 2, transfer electrodes 60 of the CCD vertical transfer sections 40 and so on are provided on the top of the substrate 100 through a gate insulating film (not shown). However, their detailed description will be omitted here because they are not directly related to the present invention.

(72) When the channel stop sections 20 and 50 are formed in the above-described solid-state imaging device, an ion implantation region is set using a specified mask and multiple times of ion implanting processes are performed with multiple ion implanting energies and impurity concentrations, so that the multilayer impurity regions 20A, 20B, 20C, and 20D and the impurity regions 50A, 50B, 50C, and 50D are formed.

(73) Thus, the channel stop sections 20 and 50 can be formed deep into the substrate 100, thereby preventing the leakage of signal charges between the devices to reduce color mixture.

(74) Since the concentration of impurity in each ion implanting process can be set as appropriate, the concentration of impurity near the surface of the substrate 100 that is formed with low implanting energy can be sufficiently ensured by making the ion concentration of impurity in an ion implanting process with relatively high implanting energy higher than that in an ion implanting process with relatively low implanting energy, so that a smear phenomenon can be prevented.

(75) When the solid-state imaging device is formed, ions are continuously implanted into the substrate 100 to form the photodiode region (light receiving section 10), the CCD vertical transfer section 40, and the respective impurity regions of the channel stop sections 20 and 50; the order thereof is not particularly limited.

(76) Also the order of the multiple times of ion implanting processes for forming the channel stop sections 20 and 50 is not particularly limited.

(77) The mask for ion implantation includes various types in addition to a general resist mask; therefore, it is not particularly limited.

(78) A specific energy and the concentration of impurity in each ion implanting process can be set as appropriate and are not particularly limited.

(79) In the embodiment, the vertical channel stop section 20 and the horizontal channel stop section 50 are separately formed so as to be optimized for the respective required characteristics, with individual ion implanting energy and impurity concentration. In FIGS. 1 and 2, although both the channel stop sections 20 and 50 have four-layer structure (or four-step ion implantation), they are not limited to that and may have a structure other than the four-layer (four-step) structure. The vertical channel stop section 20

(80) and the horizontal channel stop section 50 may not necessarily have the same number of layers.

(81) The impurity concentration may not be varied at all the layers but may be varied at part of the layers.

(82) In the above embodiment, the ion implanting processes for forming the channel stop sections 20 and 50 are carried out with multiple energies and concentrations. However, the ion implantation region is varied in each ion implanting process by changing a mask in each ion implanting process, so that the width across the channel of the respective impurity regions of the channel stop sections 20 and 50 may be varied.

(83) FIG. 3 is a sectional view of an example of the channel stop section along the vertical transfer direction. Since components other than a channel stop section 70 are the same as those of FIG. 1, they are given the same numerals and there description will be omitted.

(84) As shown in the drawing, the channel stop section 70 includes four-layer impurity regions 70A, 70B, 70C, and 70D. When the ion implanting area in an ion implanting process with relatively high implanting energy is made smaller than that in an ion implanting process with relatively low implanting energy, the reduction of the charge storage region of the light receiving section 10 in the deep part of the substrate 100 by the dispersion of P-type impurity of the channel stop section 70 can be prevented; thus, sensitivity of the light receiving section 10 and saturation signals can be increased.

(85) The energy and the impurity concentration can be set as those in FIG. 1.

(86) Although the widths of all the layers of the channel stop section 70 may be varied, only the width of part of the layers may be varied so that only the impurity regions 70A and 70B have the equal width, as shown in FIG. 3. In this case, the layers of an equal width can be formed with a common mask.

(87) The multi-step ion implantation may also be made for the channel stop section along the horizontal transfer direction, with multiple widths.

(88) The above-described embodiments offer the following advantages:

(89) (1) Referring to FIGS. 1 to 3, when multi-step ion implantation of the channel stop section between the vertical photosensors and the channel stop section between the horizontal light receiving section and the vertical transfer section is carried out with multiple energies, a color mixing phenomenon can be prevented in which photoelectrically converted charges are mixed to the adjacent photosensors.

(90) (2) Referring to FIG. 3, when the region of ion implantation with high energy reduced, a color mixing phenomenon can be prevented without narrowing the charge storage region of the light receiving section and decreasing sensitivity and saturation signal.

(91) (3) Referring to FIGS. 1 to 3, when ions are implanted into the channel stop section with high energy, the variation of an overflow barrier at charge storage can be reduced; thus the occurrence of a knee-point (Qknee) in output characteristics can be prevented.

(92) (4) When ion implantation of the channel stop section between the horizontal light receiving section and the vertical transfer section is carried out with multiple energies, a smear phenomenon near the surface and in the bulk can be prevented.

(93) In the above-described embodiments, the positional relationship of the multi-step ion implanted impurity regions is only an example, and the thickness of the impurity regions across the depth of the substrate, the shape, and the number of layers are not limited to that. For example, as shown in FIG. 4, of the multilayer impurity region of a channel stop section 80 (three-layer impurity regions 80A, 80B, and 80C in the drawing), the middle-layer impurity region (the impurity region 80B in the drawing) may be larger in thickness and also in lateral width than the other impurity regions or vice versa.

(94) As a matter of course, the multilayer ion-implanted impurity region may have a part overlapping with the upper and lower impurity regions in the strict sense.

(95) In the above embodiments, although the multilayer ion-implanted impurity region is formed such that the bottom of the lowermost-layer region has a depth substantially equal to that of the bottom of the N-type impurity region 10B in the light receiving section 10, it is not limited to that.

(96) For example, in order to prevent color mixture in a further lower region across the depth of the substrate 100, as shown in FIG. 5, the bottom of the lowermost-layer region (an impurity region 90D in the drawing) of the multilayer ion-implanted impurity region (four-layer impurity regions 90A, 90B, 90C, and 90D in the drawing) of a channel stop section 90 may be formed deeper than the bottom of the N-type impurity region 10B.

(97) As shown in FIG. 5, an overflow barrier 92 located below the light receiving section 10 and the multilayer ion-implanted impurity region (the impurity region 90D in the drawing) may be in contact with each other.

(98) In this case, the holes stored in the overflow barrier 92 can be discharged to the surface of the substrate 100 through the multilayer ion-implanted impurity region. The multilayer ion-implanted impurity region is preferably formed such that the closer to the surface of the substrate 100 the region is, the higher the concentration of the P-type impurity is.

(99) Although a preferred form of the invention has been described in which it is applied to a CCD solid-state imaging device, it is to be understood that the invention is applied not only to the CCD solid-state imaging device but also to a CMOS solid-state imaging device.

(100) As described above, by the method for manufacturing the solid-state imaging device according to the invention, the channel stop section is formed by multiple times of impurity ion implanting processes with multiple implanting energies. Thus, a multilayer impurity region can be formed across the depth of the substrate as a channel stop section.

(101) Therefore, leakage of signal charges between the adjacent photosensors and between the photosensor and the transfer section can be effectively prevented, so that a color mixing phenomenon and so on can be effectively prevented.

(102) During the multiple times of impurity ion-implantation processes, the ion implantation is carried out for multiple implantation areas, so that the dispersion of the impurity can be reduced particularly deep in the substrate, the effects to the photoelectric conversion section can be reduced, and decreases in sensitivity and saturation signals can be effectively prevented.

(103) Furthermore, during the multiple times of impurity ion-implantation processes, the ion implantation is carried out at multiple impurity concentrations, so that the respective impurity regions of the channel stop section can be formed at optimum impurity concentrations; thus anti-smear measures on the surface of the substrate can be effectively taken.

(104) Since the solid-state imaging device according to the invention includes a channel stop section having a multilayer impurity region across the depth of the substrate, leakage of signal charges between the adjacent photosensors and between the photosensor and the transfer section can be effectively prevented; thus, a color mixing phenomenon and so on can be effectively prevented.

(105) Since the multilayer impurity region of the channel stop section has multiple areas, the dispersion of impurity particularly deep in the substrate can be prevented, the effects to the photoelectric conversion section can be reduced, and decreases in sensitivity and saturation signals can be effectively prevented.

(106) Furthermore, the multilayer impurity region of the channel stop section has an optimum impurity concentration at each layer; thus anti-smear measures on the surface of the substrate can be effectively taken.

(107) While various embodiments of the present invention have been described, it will be apparent to those of skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.