CN102347336A - Image sensor - Google Patents
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- CN102347336A CN102347336A CN2010102430805A CN201010243080A CN102347336A CN 102347336 A CN102347336 A CN 102347336A CN 2010102430805 A CN2010102430805 A CN 2010102430805A CN 201010243080 A CN201010243080 A CN 201010243080A CN 102347336 A CN102347336 A CN 102347336A
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- image sensor
- shading wall
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Abstract
The invention relates to an image sensor, which comprises a substrate, at least one pixel and at least one light shield, wherein the pixel comprises a photodiode and at least one transistor, and moreover, the photodiode is connected to a metal wire through a contact part. The light shield is arranged around at least one side of the pixel, and the light shield is formed when the contact part is manufactured.
Description
Technical field
The present invention relates to transducer, especially image sensor.
Background technology
Digital camera is widely used electronic product now, and in digital camera, includes image sensor, and it is in order to convert light into electric charge; Image sensor can be divided into charge coupled device (Charge-Coupled Device) image sensor (that is being commonly called as the CCD image sensor) and CMOS (complementary metal oxide semiconductor) image sensor according to its principle that adopts, and wherein the CMOS image sensor is promptly made based on complementary metal oxide semiconductors (CMOS) (CMOS) technology.Because the CMOS image sensor is to adopt traditional cmos circuit technology to make, therefore can with image sensor with and needed peripheral circuit integrate.
In addition, the CMOS image sensor is more prone to further dwindle its employed Pixel Dimensions.Yet undersized pixel and pel array (pixel array) will (CMOS Image sensor, CIS) usefulness of system impacts to the CMOS image sensing.
Traditional CMOS image sensor system adopts front illumination (Front Side Illumination; FSI) technology is made the pixel on the pel array, and the front end (front side) that its incident light need pass through pixel could arrive light sensing zone (photo-sensing area).That is to say; The structure of traditional front illumination CMOS image sensor; Make that incident light needs just can arrive the light sensing zone afterwards through dielectric layer (dielectric layer), metal level (metal layer) earlier, and this causes the traditional cmos image sensor need face cross interference (cross talk) serious between low quantum efficiency (quantum efficiency), pixel and dark current (dark current) or the like problem.
Another CMOS image sensor is back lighting (Back Side Illumination, BSI) a CMOS image sensor.Backside illumination technology is used on the pixel of CCD image sensor originally.Be different from the front lighting technology, its front end by silicon wafer (silicon die) makes up image sensor; Back lighting CMOS image sensor makes incident light get into image sensor by the back of image sensor at the back (back side) that colored filter (color filter) and micromirror (microlens) are positioned over pixel.Compared to front illumination CMOS image sensor, this back lighting CMOS image sensor has several advantages: less light loss (light loss), slighter cross interference phenomenon, and more excellent quantum efficiency.
Yet, no matter be front illumination CMOS image sensor, or the new back lighting CMOS image sensor of releasing, all need its usefulness of lifting further badly and reduce cross interference or problem such as light loss.Therefore, need the new CMOS image sensor of proposition badly so that more superior performance to be provided.
Summary of the invention
In view of this, one of the object of the invention is to provide a kind of new image sensor structure, to promote the usefulness and the quantum efficiency thereof of CMOS image sensor.The present invention is applied to the CMOS image sensor with the shading wall construction; And aforementioned shading wall is positioned at the periphery of at least one side of pixel; Among its pairing pixel of incident light reflected back that will touch this shading wall effectively, and then effectively promote the quantum efficiency of CMOS image sensor and suppress cross interference (cross talk) between the pixel simultaneously to reduce light loss.
According to one embodiment of the invention, it provides an image sensor.This image sensor includes: substrate (substrate), at least one pixel, and at least one shading wall (1ight shield), this shading wall be positioned at this pixel at least one side around, wherein this shading wall is formed at and makes in this contact site.
Description of drawings
Shown in Figure 1 is sketch map according to the first embodiment of the present invention one back lighting (BSI) CMOS image sensor;
Shown in Figure 2 is the implementation detail of the back lighting CMOS image sensor of the first embodiment of the present invention shown in Fig. 1;
Shown in Figure 3 is the sketch map of front illumination (FSI) CMOS image sensor according to a second embodiment of the present invention;
Shown in Figure 4 is the top view of an embodiment of CMOS image sensor of the present invention;
Shown in Figure 5 is the top view of another embodiment of CMOS image sensor of the present invention.
Embodiment
In the middle of specification and follow-up claim, used some vocabulary to censure specific element.Those skilled in the art should understand, and hardware manufacturer may be called same element with different nouns.This specification and follow-up claim are not used as distinguishing the mode of element with the difference of title, but the criterion that is used as distinguishing with the difference of element on function.Be open term mentioned " comprising " in the middle of specification and the follow-up claim in the whole text, so should be construed to " comprise but be not limited to ".In addition, " couple " speech and comprise any indirect means that are electrically connected that directly reach at this.Therefore, be coupled to second device, then represent this first device can directly be electrically connected in this second device, or be electrically connected to this second device through other device or the intersegmental ground connection of connection hand if describe first device in the literary composition.
Consult Fig. 1, shown in Figure 1 is sketch map according to the first embodiment of the present invention one back lighting (BSI) CMOS image sensor.Back lighting CMOS image sensor 100 includes eyeglass 110, colored filter 120, substrate (substrate) 130, first dielectric layer (dielectric layer) 150, and the first metal wire winding layer (metal wiring layer) 160; Yet along with the difference of design requirement, back lighting CMOS image sensor 100 can have other more frameworks: the for example second metal wire winding layer, the 3rd metal wire winding layer and be sandwiched in dielectric layer wherein.In addition, know as those skilled in the art that the CMOS image sensor can include a plurality of eyeglasses, colored filter and pixel, wherein each pixel packets contains at least one photodiode (photodiode) and at least one transistor (transistor).Note that the structure of the back lighting CMOS image sensor 100 that is illustrated among Fig. 1 only is the usefulness of explanation, and is not one of them restrictive condition of the present invention.
As shown in the figure, incident light 105 arrives pixel 135 after through eyeglass 110 and colored filter 120.Eyeglass 110 is on substrate 130, and in a preferred embodiment of the present invention, it can micromirror (micro lens) be implemented.Pixel 135 includes photodiode 180 to be electronics with the photon conversion of incident according to this, and wherein, each side in pixel 135 can respectively have shallow trench isolation (Shallow Trench Isolation, STI) district 132-1 and 132-2 usually.Back lighting CMOS image sensor 100 also has contact site (contact) 155; It is arranged in first dielectric layer 150; In order to grid 140 is connected with metal wire 165, wherein grid 140 is a transistorized wherein part at this contact site 155, and transistor is corresponding to pixel 135.Owing to be not that all incident lights 105 all can successfully arrive pixel 135 traditionally, there be the photon of part may reflect/refract to contiguous pixel, and therefore cause the cross interference between pixel.In order to promote the performance of image sensor, back lighting CMOS image sensor 100 uses shading wall 170 so that incident light 105 is guided in the pixel 135 smoothly.So, place the shading wall 170 of at least one side of pixel 135 both sides that incident light is guided to pixel 135 (or photodiode 180) effectively by use, the light loss of CMOS image sensor can reduce and reduce the generation of cross interference effectively.
In order to promote the quantum efficiency of back lighting CMOS image sensor 100, can select the material of shading wall 170, can effectively the incident light that touches shading wall 170 be led back to pixel 135 to guarantee shading wall 170, and not absorb (absorb) incident light 105.Note that the material of shading wall 170 is not restricted, as long as incident light 105 can be led back to pixel 135 and not absorb incident light 105.For instance, consider that via suitable design shading wall 170 can be solid material (solid) or can be fluent material (liquid material).In a preferred embodiment of the present invention, shading wall 170 can adopt metal material to process.In addition, be effectively to reduce the complexity of fabrication schedule, shading wall 170 can be manufactured in when forming contact site 155, and the material of shading wall 170 more can select to make its material with contact site 155 identical, with further minimizing production cost; In other words, in some preferred embodiment, the material of shading wall 170 can be identical with the material of making contact site 155.Note that the position of aforementioned shading wall 170 and its material only are not one of restrictive condition of the present invention for using of explanation.For instance, via suitable design variation, shading wall 135 can be placed on back lighting CMOS image sensor 100 and be positioned on other structure of 135 pixels periphery, to reach the purpose that reduces light loss and reduce the cross interference of neighborhood pixels.Aforesaid relevant design variation all is under the jurisdiction of among the protection category of the present invention.
Consult Fig. 2, shown in Figure 2 is the implementation detail of the back lighting CMOS image sensor of the first embodiment of the present invention shown in Fig. 1.For back lighting CMOS image sensor 200, incident light 105 passes through eyeglass 110 through the guiding of shading wall 170 and reaches pixel 135 with colored filter 120.The periphery that shading wall 170 is positioned at pixel 135 is lived most incident light with circle, and the incident light reflected back pixel 135 that will touch shading wall 170, with the quantum efficiency that promotes back lighting CMOS image sensor according to this and reduce its cross interference.In addition, pixel 135 has photodiode 180 and transistor 190, and grid 140 is the part-structure of transistor 190.In the present embodiment, shading wall 170 is manufactured in when forming contact site 155, and can select the material of shading wall 170 to make its material with contact site 155 identical.
In addition, in the embodiment shown in Figure 2, grid 140 is connected to metal wire (not being shown among the figure) via contact site 155.In addition, in some preferred embodiments,, can select the material of shading wall 170 to make it not absorb incident light, more to reduce the light loss of incident light in order further to promote the usefulness of back lighting CMOS image sensor 200.In other words, the material of shading wall 170 can be along with the difference of design requirement change thereupon, for example, shading wall 170 is designed to liquid structure or solid structure along with the difference of design requirement.Yet note that except can be applicable on the back lighting CMOS image sensor, technology of the present invention also can be applicable to and adopts in the front illumination CMOS image sensor that the front lighting technology processes.
Consult Fig. 3, shown in Figure 3 is the sketch map of front illumination (FSI) CMOS image sensor according to a second embodiment of the present invention.Front illumination CMOS image sensor 300 has eyeglass 110, colored filter 120, substrate 130, first dielectric layer 150, and the first metal wire winding layer 160.And pixel 135 is in order to become photon conversion electronics, and wherein (Shallow Trench Isolation, STI) district 132-1 and 132-2 lay respectively at the both sides of pixel 135 to shallow trench isolation.Front illumination CMOS image sensor 300 also includes contact site 155, grid 140 and metal wire 165, and grid 140 is the part of transistor (not being shown among the figure); Wherein pixel 135 includes photodiode 180 and transistor.Because the structure and the running of its associated inner of front illumination CMOS image sensor 300 are well known to those skilled in the art; And the difference of back lighting CMOS image sensor and front illumination CMOS image sensor illustrated in earlier paragraphs, did not just repeat for the sake of simplicity to give unnecessary details at this.
Back lighting CMOS image sensor 100 in aforementioned first embodiment, in Fig. 3, shading wall 170 places the periphery of pixel 135.And shading wall 170 is manufactured in when forming contact site 155; And the material that can select shading wall 170 makes its material with contact site 155 identical.In some preferred embodiment, the material of shading wall 170 can be in order to form the metal material (material) of contact site 155.Yet note that the material of shading wall 170 can change along with the difference of design requirement, for example, the material of shading wall 170 can be solid material or fluent material; In fact, any can all can be selected by the material of shading wall 170 reflected back pixels 135 to make shading wall 170 with incident light 105.In addition, the material that can further select to absorb incident light 105 is made shading wall 170 in addition, further to promote quantum efficiency and to reduce cross interference.
In addition,, also can select the material of shading wall 170, make it identical with the material of making contact site 155 in order to reduce manufacturing cost.In addition, also can change shading wall 170 shapes according to the difference of design requirement, aforesaid relevant design variation also is under the jurisdiction of among the protection category of the present invention.
With reference to Fig. 4 to Fig. 5 Fig. 1 to Fig. 3, shown in Figure 4 is the top view of an embodiment of CMOS image sensor of the present invention; Shown in Figure 5 is the top view of another embodiment of CMOS image sensor of the present invention.As shown in Figure 4; The shading wall 470 of CMOS image sensor 400 is the shading wall of strip side wall (slot-shaped sidewall) structure; And in Fig. 5, the shading wall 570 of CMOS image sensor 500 is the shading wall of island side wall (island-shaped sidewall) structure.In addition, as previously mentioned, the shape of shading wall of the present invention can change along with the difference of design requirement thereupon; For example, in other embodiments of the invention, the shading wall can have finger (finger-shaped).Note that the explanation of aforementioned shape about the shading wall only is the usefulness of explanation, all design variation of shape that can promote the shading wall of CMOS image sensor usefulness also are under the jurisdiction of among the protection category of the present invention.
In addition, the position of shading wall is not limited by above stated specification also, and for example, the shading wall can be positioned at any position of the pixel of CMOD image sensor, as long as it drops on the periphery of any side of pixel.These relevant design variations also are under the jurisdiction of among the protection category of the present invention.
The above only is the preferred embodiments of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (14)
1. image sensor, it includes:
Substrate;
At least one pixel, wherein said pixel have photodiode and at least one transistor, and said transistor is connected to metal wire via contact site; And
At least one shading wall, its place said pixel at least one side around, wherein said shading wall is manufactured in when forming said contact site.
2. image sensor as claimed in claim 1, the incident light that wherein touches said shading wall reflexes to said pixel by said shading wall.
3. image sensor as claimed in claim 1, wherein said shading wall does not absorb the incident light that touches said shading wall.
4. image sensor as claimed in claim 1, wherein said shading wall is a solid.
5. image sensor as claimed in claim 4, the material of wherein said shading wall is identical with the material of the said contact site of said image sensor.
6. image sensor as claimed in claim 5, the said material of wherein said shading wall is a metal material.
7. image sensor as claimed in claim 1, wherein said shading wall is a liquid.
8. image sensor as claimed in claim 1, wherein said shading wall has the island sidewall structure.
9. image sensor as claimed in claim 1, wherein said shading wall has the strip sidewall structure.
10. image sensor as claimed in claim 1, wherein said shading wall has the finger-like sidewall structure.
11. image sensor as claimed in claim 1, wherein said image sensor also has shallow-channel isolation region, and said shallow-channel isolation region is positioned at the said photodiode outside, and said shading wall is positioned on the said shallow-channel isolation region.
12. image sensor as claimed in claim 1, wherein said image sensor adopts backside illumination technology.
13. image sensor as claimed in claim 1, wherein said image sensor adopts the front lighting technology.
14. image sensor as claimed in claim 1, it is the complementary metal oxide semiconductors (CMOS) transducer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102430805A CN102347336A (en) | 2010-07-28 | 2010-07-28 | Image sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010102430805A CN102347336A (en) | 2010-07-28 | 2010-07-28 | Image sensor |
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| CN102347336A true CN102347336A (en) | 2012-02-08 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1548921A (en) * | 2003-05-15 | 2004-11-24 | 邰志强 | Gravity induction dip angle sensor |
| CN1967856A (en) * | 2005-11-17 | 2007-05-23 | 松下电器产业株式会社 | Semiconductor image sensing element and fabrication method therefor, and semiconductor image sensing device and fabrication method therefor |
| CN101136418A (en) * | 2007-10-25 | 2008-03-05 | 上海交通大学 | Backlight type light gate type CMOS image sensor |
| US20090065821A1 (en) * | 2007-09-07 | 2009-03-12 | Sun-Chan Lee | Image sensor and fabricating method thereof |
| CN101399276A (en) * | 2007-09-24 | 2009-04-01 | 台湾积体电路制造股份有限公司 | Backside-illuminated sensor |
-
2010
- 2010-07-28 CN CN2010102430805A patent/CN102347336A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1548921A (en) * | 2003-05-15 | 2004-11-24 | 邰志强 | Gravity induction dip angle sensor |
| CN1967856A (en) * | 2005-11-17 | 2007-05-23 | 松下电器产业株式会社 | Semiconductor image sensing element and fabrication method therefor, and semiconductor image sensing device and fabrication method therefor |
| US20090065821A1 (en) * | 2007-09-07 | 2009-03-12 | Sun-Chan Lee | Image sensor and fabricating method thereof |
| CN101399276A (en) * | 2007-09-24 | 2009-04-01 | 台湾积体电路制造股份有限公司 | Backside-illuminated sensor |
| CN101136418A (en) * | 2007-10-25 | 2008-03-05 | 上海交通大学 | Backlight type light gate type CMOS image sensor |
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Application publication date: 20120208 |