CN107785389A - Imaging sensor and its manufacture method - Google Patents
Imaging sensor and its manufacture method Download PDFInfo
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Classifications
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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
- H01L27/14643—Photodiode arrays; MOS imagers
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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
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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
- H01L27/1464—Back illuminated imager structures
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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
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
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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
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14698—Post-treatment for the devices, e.g. annealing, impurity-gettering, shor-circuit elimination, recrystallisation
Abstract
This disclosure relates to imaging sensor and its manufacture method.One of embodiment provides a kind of method for manufacturing imaging sensor, and it includes：From the front of Semiconductor substrate, N type dopant is injected into Semiconductor substrate, so as to form the N-type region of photodiode in the semiconductor substrate；From the back side of Semiconductor substrate, Semiconductor substrate is thinned；The back side of Semiconductor substrate after being thinned, the implanting p-type dopant into a part for N-type region, so as to form at least a portion of the p type island region of photodiode；And laser annealing is carried out to described at least a portion of p type island region, so as to activate the P-type dopant of injection.
Description
Technical field
This disclosure relates to field of image sensors.
Background technology
Back-illuminated type (BSI) cmos image sensor (CIS) has obtained more and more extensive use at present.In order to improve constantly
The performance of the imaging sensor, those skilled in the art pursue always higher full-well capacity (full well capacity),
Higher quantum efficiency (quantum efficiency), lower dark current etc..
Therefore the demand for new technology be present.
The content of the invention
One purpose of the disclosure is to provide a kind of novel image sensor architecture and corresponding manufacture method.
According to the first aspect of the disclosure, there is provided a kind of imaging sensor, it includes：Semiconductor substrate, in semiconductor
It is inverted U shape in substrate formed with photodiode, the N-type region of wherein photodiode, at least the one of the p type island region of photodiode
Part is surrounded by inverted U-shaped N-type region, and N-type region than p type island region described at least a portion closer to Semiconductor substrate just
At least a portion in face, wherein p type island region is by activating p-type from the injection of the back side of Semiconductor substrate and laser annealing and mixing
Miscellaneous dose and formed.
According to the second aspect of the disclosure, there is provided a kind of method for manufacturing imaging sensor, it includes：Served as a contrast from semiconductor
The front at bottom, N type dopant is injected into Semiconductor substrate, so as to form the N-type region of photodiode in the semiconductor substrate；
From the back side of Semiconductor substrate, Semiconductor substrate is thinned；The back side of Semiconductor substrate after being thinned, to N-type region
Implanting p-type dopant in a part, so as to form at least a portion of the p type island region of photodiode；And to described in p type island region
At least a portion carries out laser annealing, so as to activate the P-type dopant of injection.
By referring to the drawings to the present invention exemplary embodiment detailed description, further feature of the invention and its
Advantage will become more apparent from.
Brief description of the drawings
The accompanying drawing of a part for constitution instruction describes embodiment of the disclosure, and is used to solve together with the description
Release the principle of the disclosure.
Referring to the drawings, according to following detailed description, the disclosure can be more clearly understood, wherein：
Fig. 1 shows the sectional view of the imaging sensor according to disclosure exemplary embodiment.
Fig. 2A -2C show the section of some alternate embodiments of the imaging sensor according to disclosure exemplary embodiment
Figure.
Fig. 3 shows the flow chart of the method for making image sensor according to disclosure exemplary embodiment.
Fig. 4 A-4D respectively illustrate is manufacturing imaging sensor side according to one exemplary embodiment of the disclosure
Device schematic cross-section at each step of method example.
Pay attention to, in embodiments described below, be used in conjunction with same reference between different accompanying drawings sometimes
Come the part for representing same section or there is identical function, and omit its repeat specification.In this manual, using similar mark
Number and letter represent similar terms, therefore, once be defined in a certain Xiang Yi accompanying drawing, then in subsequent accompanying drawing do not need pair
It is further discussed.
In order to make it easy to understand, position, size and scope of each structure shown in accompanying drawing etc. etc. does not indicate that reality sometimes
Position, size and scope etc..Therefore, disclosed invention is not limited to position, size and scope disclosed in accompanying drawing etc. etc..
Embodiment
It is described in detail the various exemplary embodiments of the disclosure below with reference to accompanying drawings.It should be noted that：Unless have in addition
Body illustrates that the unlimited system of part and the positioned opposite of step, numerical expression and the numerical value otherwise illustrated in these embodiments is originally
Scope of disclosure.
The description only actually at least one exemplary embodiment is illustrative to be never used as to the disclosure below
And its application or any restrictions that use.That is, semiconductor device and its manufacture method herein is with exemplary
Mode is shown, to illustrate the different embodiments of the structures and methods in the disclosure.It will be understood by those skilled in the art, however, that
They are merely illustrative the exemplary approach of the invention that can be used for implementing, rather than the mode of limit.In addition, accompanying drawing need not be by
Ratio is drawn, and some features may be exaggerated to show the details of specific component.
It may be not discussed in detail for technology, method and apparatus known to person of ordinary skill in the relevant, but suitable
In the case of, the technology, method and apparatus should be considered as authorizing part for specification.
In shown here and discussion all examples, any occurrence should be construed as merely exemplary, without
It is as limitation.Therefore, the other examples of exemplary embodiment can have different values.
Inventors herein have recognized that the full-well capacity of photodiode is generally directly proportional to its electric capacity, therefore, in order to carry
High full-well capacity, it may be considered that increase the area of the PN junction of photodiode, so as to increase electric capacity.This is inventors herein proposed and adopted
The structure (such as illustrated in fig. 1) of part p type island region is surrounded with a kind of inverted U-shaped N-type region, so as to be added significantly to the area of PN junction
And it ensure that photodiode normal work.Therefore, the structure can increase full-well capacity, in the case of increasing half-light
Resolution ratio.
In the structure shown here, p type island region part (hereinafter also referred to as " the p-type main body (P-body) surrounded by inverted U-shaped N-type region
Area ") formed typically by the N-type region intermediate ion implanting p-type dopant.
However, inventors herein have recognized that, because the depth injected from substrate face is larger, therefore usually require
More than 1000KeV Implantation Energy (such as 1000K~3000KeV) could be realized, and so high Implantation Energy is easy to
Defect is produced around injection Ion paths, subsequent anneal processing can only repair a part, and remaining defect shows as dark current, is formed
White pixel phenomenon.On the other hand, with BSI CIS development, the substrate more and more thinner in BSI CIS structures, carried out from the back side
Ion implanting is possibly realized.Therefore, present inventor proposes, from the back side to the one of N-type region after substrate back is thinned
Implanting p-type dopant in point, so as to form above-mentioned new construction.As substrate is thinning and the PN junction of photodiode is rearwardly stretched
Exhibition, the depth from front injection is smaller than from the depth of back side injection, therefore Implantation Energy is with the reduction of BSI CIS substrate thickness
And reduce, processing platform is easily realized.In addition, this avoid damage of the energetic ion to substrate face, reduce dark current.
But present inventor is it has furthermore been found that such back side injection processing there may be compatibility issue.It is former
Because being that must be made annealing treatment after ion implanting to carry out active ions, and now the positive metal level of device has completed, by
Metal limits, and chip front side temperature can not be too high during annealing, such as no more than 400 DEG C, and this can limit the effect of annealing.
By further investigation, it is contemplated that the above, present inventor are proposed using laser annealing to activate p-type
The P-type dopant of body region, this can at least bring following benefit：1st, in the case where not influenceing device and having formed structure, effectively
Activate dopant；2nd, compared with conventional activation mode, effective activity ratio is high, and impurity is efficient to be improved；3rd, Local activation can be realized,
Impurity Distribution without influenceing other impurity ranges.
It note that herein, term " p-type main body (P-body) area " is a kind of call in technique or design, is referred to
In generation, injects the p type island region of formation in N-type region in the structure of the present invention.
Technical scheme is described in more detail below in conjunction with accompanying drawing.
Fig. 1 shows the sectional view of the imaging sensor according to disclosure exemplary embodiment.As shown in figure 1, image passes
Sensor includes Semiconductor substrate 101, formed with photodiode in the Semiconductor substrate 101.Photodiode is by N-type region
102 and the p type island region including p-type main body (P-body) area 103 formed, wherein N-type region 102 than p-type body region 103 closer to partly leading
Body substrate 101 front and be inverted U shape, p-type body region 103 is located in the inverted U-shaped opening of N-type region 102, i.e., by N-type region
102 surround.
The structure contacted by forming inverted U-shaped N-type region 102 as shown in Figure 1 with p type island region, the area of PN junction is added, and
And preferable depletion layer distribution can be realized.Therefore, the structure can increase full-well capacity, and realize the more excellent pole of photoelectricity two
Pipe operating characteristics.
In Fig. 1, substrate 101 is p-type doping, therefore the p type island region of photodiode can include p-type body region 103
And below N-type region 102 and both sides P type substrate region.However, those skilled in the art be understood that the invention is not restricted to
This.For example, in some other embodiment, substrate 101 can be intrinsic or n-type doping, and photodiode is by shape
Into in P type trap zone, now the p type island region of photodiode can include a part for P type trap zone.In addition, in some embodiment party
, can be on monocrystalline silicon wafer by being epitaxially-formed epitaxial semiconductor layer in formula, and device is formed and partly led in the extension
In body layer.That is, substrate 101 can include monocrystalline silicon wafer and the epitaxial semiconductor layer of its Epitaxial growth.At some
In the case of, the epitaxial semiconductor layer can be the P-type layer of doping in situ, the part as the p type island region of photodiode.
In addition, the consideration realized based on above-mentioned technique, in the present invention, p-type body region 103 is by from semiconductor
Back side injection and the laser annealing activation P-type dopant of substrate and formed, the defects of so as to reduce device front and
Corresponding dark current.In some embodiments, the P-type dopant injected can be boron (B) ion, or be boracic chemical combination
Thing, such as BF2.In some embodiments, implantation dosage can be in 5E11 to 5E13cm-2In the range of.
In some embodiments, the thickness of Semiconductor substrate 101 is less than or equal to 4 microns.It is highly preferred that semiconductor serves as a contrast
The thickness at bottom 101 is in the range of 2-3 microns, for example, 2.5 microns.In some embodiments, under p-type body region 103
Can be 0.1-0.5 microns along the distance away from the back side.
In some embodiments, the imaging sensor is additionally included in the gold that the upper front of Semiconductor substrate 101 is formed
Belong to line (not shown).Those skilled in the art understand, these metal connecting lines are used to connect each device and form circuit, can be with
Formed by any common process.
In addition, in some preferred embodiments, can in order to which the doping concentration to N-type region 102, pattern etc. optimize
To form N-type region 102 in two steps, so as to which N-type region 102 is segmented into positive first N-type region 104 close to Semiconductor substrate
And the second N-type region 105 under the first N-type region 104, as seen in figs. 2a-2c.Fig. 2A -2C are shown according to disclosure example
The sectional view of some alternate embodiments of the imaging sensor of property embodiment.
In the structure shown in Fig. 2A, the positive surface of close Semiconductor substrate and two sides of p-type body region 103 are equal
Surrounded by the second N-type region 105.
In the structure shown in Fig. 2 B, the positive surface of close Semiconductor substrate of p-type body region 103 is close to the first N-type
Area 104, and two sides are close to the second N-type region 105.Those skilled in the art are understood that, a part for p-type body region 103
It can also stretch into the first N-type region 104, can also be close to the first N-type region 104 so as to the top of two side.The tool of the structure
Body design depends on practical application and/or technological operation, such as the ion implanting of p-type body region 103 and the technique of laser annealing
The profile of p-type body region 103 can be influenceed.
In the structure shown in Fig. 2 C, it is positive with photodiode pair that the imaging sensor is additionally included in Semiconductor substrate
Second p type island region 106 of the opening position answered, the second p type island region 106 are P+ areas (heavily doped P-type area), and its doping concentration is higher than photoelectricity two
The doping concentration of the p type island region (such as p-type body region 103, P type substrate, P type trap zone etc.) of pole pipe.Using front at Gai P+ areas,
Dark current can further be reduced.
In some embodiments, in the structure shown in Fig. 2A -2C, the doping concentration of the first N-type region 104 is higher than second
The doping concentration of N-type region 105.For example, the first N-type region 104 can be intermediate doping concentration, and the second N-type region 105 is N- areas
(lightly doped district).
Fig. 3 shows the flow chart of the method for making image sensor 300 according to disclosure exemplary embodiment.
Specifically, as shown in figure 3, at step 310, from the front of Semiconductor substrate, N is injected into Semiconductor substrate
Type dopant, so as to form the N-type region of photodiode in the semiconductor substrate.
In some embodiments, can inject in two steps to form N-type region, so as to which N-type region is segmented into close to partly leading
Positive first N-type region and the second N-type region under the first N-type region of body substrate, as seen in figs. 2a-2c.Preferably, first
The doping concentration of N-type region is higher than the doping concentration of the second N-type region.
In some embodiments, can also be formed in the positive opening position corresponding with photodiode of Semiconductor substrate
P+ areas.
In some embodiments, metal connecting line can also be formed in the upper front of Semiconductor substrate.
At step 320, from the back side of Semiconductor substrate, Semiconductor substrate is thinned.
In some embodiments, the thickness of the Semiconductor substrate after being thinned is less than or equal to 4 microns.It is highly preferred that subtract
The thickness of Semiconductor substrate after thin is in the range of 2-3 microns.
At step 330, the back side of the Semiconductor substrate after being thinned, into a part for N-type region, implanting p-type is adulterated
Agent, so as to form at least a portion of the p type island region of photodiode.
In some embodiments, implantation dosage is in 5E11 to 5E13cm-2In the range of.
At step 340, laser annealing is carried out to described at least a portion of p type island region, so as to activate the doping of the p-type of injection
Agent.
In some embodiments, ensure that the positive temperature of Semiconductor substrate is equal to or less than 400 DEG C during laser annealing.
In some embodiments, the optical maser wavelength that is used in laser annealing is less than or equal to 400nm, pulsed laser energy 0.5~
In the range of 3.5J, Laser pulse time is in the range of 100~600ns.
In order to more complete and comprehensive understand the present invention, will come below by taking the image sensor architecture shown by Fig. 2 C as an example detailed
A thin specific example for describing the method for making image sensor according to one exemplary embodiment of the disclosure.It note that this
Individual example is not intended to be construed as limiting the invention.For example, the present invention is not limited in the concrete structure shown by Fig. 2 C, and
It is that all image sensor architectures for having same requirements or design consideration are all suitable for.Above in conjunction with Fig. 1, Fig. 2A -2C and Fig. 3 institutes
The content of description is readily applicable to corresponding feature.
Fig. 4 A-4D respectively illustrate the device schematic cross-section at each step of this method example.This method example
Especially suitable for back-illuminated cmos image sensors.
At Fig. 4 A, Semiconductor substrate 101 can be monocrystalline silicon disk, with follow-up carrying wafer bonding, be thinned before
Any conventional means can be utilized in the positive semiconductor devices for forming imaging sensor and being included of disk except p-type main body
Other components outside area 103.Certainly, metal connecting line can be formed in upper front, circuit is formed for connecting each device.
Because the present invention focuses on structure and the manufacture of photodiode, therefore the photoelectricity two in substrate is referred primarily at this
The manufacturing process of pole pipe.Specifically, same mask can be utilized, is noted at twice thereto from the front of Semiconductor substrate 101
Enter N type dopant, so as to form the first N-type region 104 of photodiode and the second N-type region under the first N-type region 104
105.That is, the first N-type region 104 that ion implanting forms intermediate doping concentration is first passed through, then, the higher Implantation Energy doping of use
Form the second N-type region 105 as lightly doped district (N- areas).In addition, after the second N-type region 105 is formed, can also partly lead
The opening position corresponding with photodiode of body substrate face forms P+ areas 106 (heavily doped P-type area).The doping in the P+ areas 106
Doping concentration of the concentration higher than the p type island region (such as p-type body region 103, P type substrate, P type trap zone etc.) of photodiode.Utilize
Gai P+ areas 106 at front, can further reduce dark current.
In Figure 4 A, substrate 101 is p-type doping, and the region of photodiode can be formed directly into substrate.So
And those skilled in the art are understood that the invention is not restricted to this.For example, in some other embodiment, substrate 101 can be with
It is intrinsic or n-type doping, photodiode are formed in P type trap zone, now the p type island region of photodiode can wrap
Include a part for P type trap zone.In addition, in some embodiments, can be outer by being epitaxially-formed on monocrystalline silicon wafer
Prolong semiconductor layer, and device is formed in the epitaxial semiconductor layer.That is, substrate 101 can include monocrystalline silicon wafer
With the epitaxial semiconductor layer of its Epitaxial growth.In some cases, the epitaxial semiconductor layer can be the p-type of doping in situ
Layer, the part as the p type island region of photodiode.
At Fig. 4 B, the front of Semiconductor substrate 101 is bonded with carrying disk (not shown), and is served as a contrast from semiconductor
The back side at bottom, Semiconductor substrate 101 is ground thinned.It is micro- that the thickness of Semiconductor substrate 101 after being thinned is less than or equal to 4
Rice.It is highly preferred that be thinned after Semiconductor substrate 101 thickness in the range of 2-3 microns, most preferably 2.5 microns.Subtract
Thin technique is unrestricted, and can be any any means known.
At Fig. 4 C, by being lithographically formed the injection window of p-type body region 103 on the back side of the Semiconductor substrate after being thinned
Mouthful, then from the back side into the center section of N-type region 105 implanting p-type dopant 107, so as to form p-type body region 103.P-type
The doping concentration of body region 103 can be equal to or more than the doping concentration of p type single crystal silicon substrate 101.Control p-type body region
103 profile or position, to ensure that p-type body region 103 contacts with the P type substrate region of lower section, so as to form photoelectricity two together
The p type island region of pole pipe, it not allow p-type body region 103 floating or be embedded in N-type region 105.The P-type dopant injected can be
Boron (B) ion, or be boron-containing compound, such as BF2.Implantation dosage can be in 5E11 to 5E13cm-2In the range of.
The energy of back side injection, depth etc. are mainly determined by device structure design, but the back side is noted under many circumstances
The depth entered is shallower, for example, distance of the lower edge of p-type body region 103 away from the back side can be 0.1-0.5 microns, therefore injects energy
Amount can be such as 5-50KeV, either 1-5KeV or be 25KeV or so.Shallower depth also implies that photodiode
The position of PN junction is close far from the back side, so as to improve the collection efficiency to carrier caused by the light of back surface incident.
At Fig. 4 D, p-type body region 103 is annealed using laser 108, so as to activate the P-type dopant of injection.Swash
To ensure that the positive temperature of Semiconductor substrate is equal to or less than 400 DEG C during photo-annealing.Pulse laser can be used to add the side of scanning
Formula carries out laser annealing.The optical maser wavelength used can be less than or equal to 400nm, and pulsed laser energy can be in 0.5~3.5J
In the range of, Laser pulse time can be in the range of 100~600ns.In some alternative embodiments, according to reality
Situation, it can be annealed using continuous laser.
The P-type dopant of p-type body region is activated by using laser annealing, structure can have been formed not influenceing device
In the case of, dopant is more effectively activated, and Local activation can be realized, the impurity point without influenceing other impurity ranges
Cloth.
In some alternative embodiments, can first be injected at Fig. 4 C with low energy to be formed very shallow p type island region (such as
0.1 micron of depth or more shallow), the depth of the p type island region is then pushed further into laser annealing at Fig. 4 D, so as to obtain p-type master
Body area 103 (such as reaching 0.3 micron or deeper).This can further reduce back side Implantation Energy, simplify technique, reduce defect.
And it so may more preferably control profile or the position of p-type body region 103.
In other alternative embodiments, Semiconductor substrate can be integrally first heated to 200-300 at Fig. 4 D
The annealing of p-type body region 103 degree Celsius is carried out with laser again, so can further improve annealing efficiency.
It will be understood by those skilled in the art that in addition to technique and structure as illustrated, the disclosure also includes forming figure
As other any techniques and structure necessary to sensor.
By the method example shown by above-mentioned Fig. 4 A-4D, corresponding novel work is combined using the novel structure of the present invention
Skill, the raising of full-well capacity can be realized in the case where not deteriorating other performance (such as dark current).
Word "front", "rear", " top ", " bottom " in specification and claim, " on ", " under " etc., if deposited
If, it is not necessarily used to describe constant relative position for descriptive purposes.It should be appreciated that the word so used
Language is interchangeable in appropriate circumstances so that embodiment of the disclosure described herein, for example, can with this institute
Those of description show or other are orientated in other different orientations and operated.
As used in this, word " exemplary " means " being used as example, example or explanation ", not as will be by
" model " accurately replicated.It is not necessarily to be interpreted than other implementations in any implementation of this exemplary description
Preferable or favourable.Moreover, the disclosure is not by above-mentioned technical field, background technology, the content of the invention or embodiment
Given in the theory that is any stated or being implied that goes out limited.
As used in this, word " substantially " mean comprising by design or manufacture the defects of, device or element appearance
Any small change caused by difference, environment influence and/or other factorses.Word " substantially " also allows by ghost effect, made an uproar
Caused by sound and the other actual Considerations being likely to be present in actual implementation with perfect or preferable situation
Between difference.
In addition, just to the purpose of reference, can with the similar terms such as " first " used herein, " second ", and
And thus it is not intended to limit.For example, unless clearly indicated by the context, be otherwise related to structure or element word " first ", "
Two " do not imply order or sequence with other such digital words.
It should also be understood that the word of "comprises/comprising" one is as used herein, illustrate pointed feature, entirety, step be present
Suddenly, operation, unit and/or component, but it is not excluded that in the presence of or the one or more of the other feature of increase, entirety, step, behaviour
Work, unit and/or component and/or combinations thereof.
In the disclosure, therefore term " offer " " it is right to provide certain from broadly by covering obtain object all modes
As " including but not limited to " purchase ", " preparation/manufacture ", " arrangement/setting ", " installation/assembling ", and/or " order " object etc..
Foregoing description can indicate to be " connected " or " coupling " element together or node or feature.As used herein
, unless otherwise expressly noted, " connection " means an element/node/feature with another element/node/feature in electricity
Above, mechanically, in logic or otherwise it is directly connected (or direct communication).Similarly, unless otherwise expressly noted,
" coupling " mean an element/node/feature can with another element/node/feature in a manner of direct or be indirect in machine
On tool, electrically, in logic or otherwise link to allow to interact, even if the two features may be not direct
Connection is also such.That is, " coupling " is intended to encompass the direct link of element or further feature and linked indirectly, including profit
With the connection of one or more intermediary elements.
It should be appreciated by those skilled in the art that the border between aforesaid operations is merely illustrative.Multiple operations
Single operation can be combined into, single operation can be distributed in additional operation, and operate can at least portion in time
Divide and overlappingly perform.Moreover, alternative embodiment can include multiple examples of specific operation, and in other various embodiments
In can change operation order.But others are changed, variations and alternatives are equally possible.Therefore, the specification and drawings
It should be counted as illustrative and not restrictive.
In addition, embodiment of the present disclosure can also include the example below：
A kind of 1. imaging sensor, it is characterised in that including：
Semiconductor substrate, in the semiconductor substrate formed with photodiode, wherein the N-type region of photodiode is in U
Shape, at least a portion of the p type island region of photodiode are surrounded by inverted U-shaped N-type region, and N-type region than described in p type island region at least
A part closer to the front of Semiconductor substrate,
Described at least a portion of wherein p type island region is by being activated from the injection of the back side of Semiconductor substrate and laser annealing
P-type dopant and formed.
2. the imaging sensor according to 1, it is characterised in that the thickness of Semiconductor substrate is less than or equal to 4 microns.
3. the imaging sensor according to 2, it is characterised in that the thickness of Semiconductor substrate is in the range of 2-3 microns.
4. the imaging sensor according to 1, it is characterised in that N-type region includes positive the close to Semiconductor substrate
One N-type region and the second N-type region under the first N-type region.
5. the imaging sensor according to 4, it is characterised in that at least one of close semiconductor of p type island region
The surface of substrate face is close to the first N-type region, and two sides are close to the second N-type region.
6. the imaging sensor according to 4, it is characterised in that at least one of close semiconductor of p type island region
The surface of substrate face and two sides are surrounded by the second N-type region.
7. the imaging sensor according to 1, it is characterised in that it is positive with the pole of photoelectricity two to be additionally included in Semiconductor substrate
Second p type island region of opening position corresponding to pipe, the second p type island region are P+ areas and doping concentration mixing higher than the p type island region of photodiode
Miscellaneous concentration.
8. the imaging sensor according to 1, it is characterised in that be additionally included in the upper front formation of Semiconductor substrate
Metal connecting line.
9. the imaging sensor according to 4, it is characterised in that the doping concentration of the first N-type region is higher than the second N-type region
Doping concentration.
10. the imaging sensor according to 1, it is characterised in that the p-type doping in described at least a portion of p type island region
Agent is boron-containing compound.
A kind of 11. method for manufacturing imaging sensor, it is characterised in that including：
From the front of Semiconductor substrate, N type dopant is injected into Semiconductor substrate, so as to be formed in the semiconductor substrate
The N-type region of photodiode；
From the back side of Semiconductor substrate, Semiconductor substrate is thinned；
The back side of Semiconductor substrate after being thinned, the implanting p-type dopant into a part for N-type region, so as to form light
At least a portion of the p type island region of electric diode；And
Laser annealing is carried out to described at least a portion of p type island region, so as to activate the P-type dopant of injection.
12. the method according to 11, it is characterised in that the implantation dosage in the step of implanting p-type dopant exists
In the range of 5E11 to 5E13cm-2.
13. the method according to 11, it is characterised in that the positive temperature of Semiconductor substrate is equal to or small during laser annealing
In 400 DEG C.
14. the method according to 11, it is characterised in that it is micro- that the thickness of the Semiconductor substrate after being thinned is less than or equal to 4
Rice.
15. the method according to 14, it is characterised in that model of the thickness of the Semiconductor substrate after being thinned in 2-3 microns
In enclosing.
16. the method according to 11, it is characterised in that N-type region includes positive first N-type close to Semiconductor substrate
Area and the second N-type region under the first N-type region, P-type dopant are infused in the center section of the second N-type region.
17. the method according to 11, it is characterised in that it is positive that Semiconductor substrate is additionally included in before reduction steps
Opening position corresponding with photodiode forms P+ areas.
18. the method according to 11, it is characterised in that the front of Semiconductor substrate is additionally included in before reduction steps
Top forms metal connecting line.
19. the method according to 11, it is characterised in that the optical maser wavelength used in laser annealing is less than or equal to
400nm。
20. the method according to 11, it is characterised in that the pulsed laser energy used in laser annealing 0.5~
In the range of 3.5J.
21. the method according to 11, it is characterised in that the Laser pulse time in laser annealing is in 100~600ns
In the range of.
22. the method according to 16, it is characterised in that the doping concentration of the first N-type region is higher than the doping of the second N-type region
Concentration.
Although some specific embodiments of the disclosure are described in detail by example, the skill of this area
Art personnel it should be understood that above example merely to illustrate, rather than in order to limit the scope of the present disclosure.It is disclosed herein
Each embodiment can in any combination, without departing from spirit and scope of the present disclosure.It is to be appreciated by one skilled in the art that can be with
A variety of modifications are carried out to embodiment without departing from the scope of the present disclosure and spirit.The scope of the present disclosure is limited by appended claims
It is fixed.
Claims (10)
- A kind of 1. imaging sensor, it is characterised in that including：Semiconductor substrate, it is inverted U shape in the semiconductor substrate formed with photodiode, the N-type region of wherein photodiode, light At least a portion of the p type island region of electric diode is surrounded by inverted U-shaped N-type region, and N-type region is than at least one described in p type island region Divide closer to the front of Semiconductor substrate,Described at least a portion of wherein p type island region is by activating p-type from the injection of the back side of Semiconductor substrate and laser annealing Dopant and formed.
- 2. imaging sensor according to claim 1, it is characterised in that it is micro- that the thickness of Semiconductor substrate is less than or equal to 4 Rice.
- 3. imaging sensor according to claim 2, it is characterised in that model of the thickness of Semiconductor substrate in 2-3 microns In enclosing.
- 4. imaging sensor according to claim 1, it is characterised in that N-type region is included close to the front of Semiconductor substrate The first N-type region and the second N-type region under the first N-type region.
- 5. imaging sensor according to claim 4, it is characterised in that described at least one of close the half of p type island region The surface of conductor substrate face is close to the first N-type region, and two sides are close to the second N-type region.
- 6. imaging sensor according to claim 4, it is characterised in that described at least one of close the half of p type island region The surface of conductor substrate face and two sides are surrounded by the second N-type region.
- 7. imaging sensor according to claim 1, it is characterised in that be additionally included in that Semiconductor substrate is positive and photoelectricity Second p type island region of opening position corresponding to diode, the second p type island region are the p type island region that P+ areas and doping concentration are higher than photodiode Doping concentration.
- 8. imaging sensor according to claim 1, it is characterised in that be additionally included in the upper front shape of Semiconductor substrate Into metal connecting line.
- 9. imaging sensor according to claim 4, it is characterised in that the doping concentration of the first N-type region is higher than the second N-type The doping concentration in area.
- 10. imaging sensor according to claim 1, it is characterised in that the p-type in described at least a portion of p type island region Dopant is boron-containing compound.
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