CN110349987A

CN110349987A - Phase-detection auto-focusing pixel element and forming method thereof, imaging sensor and forming method thereof

Info

Publication number: CN110349987A
Application number: CN201910638161.6A
Authority: CN
Inventors: 黄增智; 倪凌云; 黄晓橹
Original assignee: Huaian Imaging Device Manufacturer Corp
Current assignee: Huaian Xide Industrial Design Co ltd
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2019-10-18
Anticipated expiration: 2039-07-15
Also published as: CN110349987B

Abstract

This application involves technical field of semiconductors, more particularly to a kind of phase-detection auto-focusing pixel element and forming method thereof and imaging sensor and forming method thereof.The phase-detection auto-focusing pixel element (PDAF) includes: semiconductor substrate, and the semiconductor substrate includes at least two pixel regions；Antireflection layer, the antireflection layer are located in the semiconductor substrate；At least two bury lens, and at least two burials lens are located on the antireflection layer, and position corresponds at least two pixel region.The burial lens can assemble the light being injected into PDAF pixel element, increase the light-inletting quantity of the PDAF pixel element, increase the light intensity difference in the PDAF element between pixel region, increases the PDAF pixel element to the response angle of light, improve focusing sensitivity.

Description

Phase-detection auto-focusing pixel element and forming method thereof, imaging sensor and its Forming method

Technical field

This application involves technical field of semiconductors, more particularly to a kind of phase-detection auto-focusing pixel element and its shape At method, and the imaging sensor and forming method thereof comprising the phase-detection auto-focusing pixel element.

Background technique

Imaging sensor is a kind of device that optical imagery is converted into electric signal.With the hair of computer and communications industry Exhibition, the demand to high-performance image sensors constantly increase, these high-performance image sensors are widely used in such as Digital photographic The various necks of machine, camcorders, PCS Personal Communications System (PCS), game machine, security monitoring video camera, medical miniature camera etc Domain.

It may include the pixel unit for imaging and the picture for realizing camera lens auto-focusing in image sensor array Plain unit.A kind of method that realizing auto-focusing is called phase-detection auto-focusing (Phase detective auto Focusing, PDAF).Fig. 1 is a kind of structural schematic diagram of PDAF pixel unit in the prior art.The PDAF pixel includes It is formed with the semiconductor substrate 110 of at least two photosensitive elements 120, the semiconductor substrate 110 includes at least two pixel regions Domain 111, at least two photosensitive element 120 correspond respectively at least two pixel region 111；Deep trench isolation structure 130, between described two pixel regions 111, for reducing the light crosstalk between adjacent pixel regions；Antireflection layer 140, The antireflection layer 140 is located in the semiconductor substrate 110；Colour filter 150, the colour filter 150 are located at the antireflection layer 140 On, across at least two pixel region 111；Lenticule 160 is located on the colour filter 150, across described at least two Pixel region 111.

The PDAF pixel is symmetrical in image sensor array, when described image sensor gets the figure of object When picture, it can be obtained by detecting the light intensity difference of two pixel regions 111 in symmetrical PDAF pixel, then by algorithm process To the location information of object, so that the back-and-forth motion of camera lens be instructed to realize auto-focusing.

However the PDAF pixel in conventional images sensor is smaller to the response angle of light, the light intensity difference detected Not smaller, focusing sensitivity is not high, it is therefore necessary to develop a kind of new imaging sensor that can be realized auto-focusing.

Summary of the invention

The application provides a kind of phase-detection auto-focusing pixel element and forming method thereof, and includes phase inspection The imaging sensor and forming method thereof of auto-focusing pixel element is surveyed, to improve the phase-detection auto-focusing pixel element Focusing sensitivity.

The one aspect of the application provides a kind of phase-detection auto-focusing pixel element, comprising: semiconductor substrate, it is described Semiconductor substrate includes at least two pixel regions；Antireflection layer, the antireflection layer are located in the semiconductor substrate；At least two Lens are buried, at least two burials lens are located on the antireflection layer, and position corresponds at least two pixel region； Colour filter, the colour filter are located on the antireflection layer, and cover described at least two and bury lens；Lenticule is located at institute It states on colour filter, across at least two pixel region.

In some embodiments of the present application, it is described at least two bury lens material be fusing point 300 degrees Celsius with On transparent dielectric material.

In some embodiments of the present application, described at least two materials for burying lens are silica, aluminium oxide, oxidation Hafnium, zirconium oxide, any one in silicon nitride.

In some embodiments of the present application, it is described at least two bury lens with a thickness of 100 nanometers to 900 nanometers.

In some embodiments of the present application, the anti-reflection layer material is that fusing point can be improved at 300 degrees Celsius or more The transparent dielectric material of light penetration.

In some embodiments of the present application, the anti-reflection layer material is aluminium oxide, in hafnium oxide, zirconium oxide, silicon nitride Any one or it is a variety of.

In some embodiments of the present application, the antireflection layer is the storehouse that one layer of transparent dielectric material described above is formed Structure.

The one aspect of the application also provides a kind of forming method of phase-detection auto-focusing pixel element, comprising: mentions For semiconductor substrate, the semiconductor substrate includes at least two pixel regions；Antireflection layer is formed on the semiconductor substrate； At least two are formed on the antireflection layer and buries lens, and described at least two, which bury lens position, corresponds to described at least two Pixel region；It is buried in the antireflection layer and described at least two and forms colour filter on lens, described in the colour filter covering At least two bury lens；Lenticule is formed on the colour filter, the lenticule is across at least two pixel region.

In some embodiments of the present application, the anti-reflection layer material is in aluminium oxide, hafnium oxide, zirconium oxide and silicon nitride Any one or it is a variety of.

In some embodiments of the present application, the method that at least two burial lens are formed on the antireflection layer includes: It is formed on the antireflection layer and buries lens material layer；Photoresist layer is formed on the burial lens material layer；Patterning institute Photoresist layer is stated, keeps the pattern of the photoresist layer consistent at least two burial figure of lens；Flow back the pattern The photoresist layer of change；Using the patterned photoresist layer as exposure mask, the burial lens material layer is etched, the burial is formed Lens；Remove the patterned photoresist layer.

In some embodiments of the present application, the temperature for the patterned photoresist layer that flows back is 50 degrees Celsius to 150 Degree Celsius, return time is 0.5 minute to 3 minutes.

Further aspect of the application provides a kind of imaging sensor, comprising: semiconductor substrate, the semiconductor substrate At least one first pixel region and at least two second pixel regions are included, second pixel region is used to form phase-detection Auto-focusing pixel element；Antireflection layer is located in the semiconductor substrate；At least two bury lens, are located at the antireflection layer On, position is corresponding with second pixel region；First colour filter and the second colour filter are located on the antireflection layer, described The position of first colour filter is corresponding at least one described first pixel region, the position of second colour filter and it is described at least Two the second pixel regions and at least two burials lens are corresponding；Grid is isolated, is located on the antireflection layer, and is isolated and appoints It anticipates adjacent first colour filter and the second colour filter；First lenticule and the second lenticule, first lenticule position In on first colour filter, second lenticule is located on second colour filter, and second lenticule is across described At least two second pixel regions.

Further aspect of the application also provides a kind of forming method of imaging sensor, comprising: semiconductor substrate is provided, The semiconductor substrate includes at least one first pixel region and at least two second pixel regions, second pixel region It is used to form phase-detection auto-focusing pixel element；Antireflection layer is formed on the semiconductor substrate；On the antireflection layer It forms at least two and buries lens, described at least two, which bury lens position, corresponds to second pixel region；In the increasing Isolation grid is formed in permeable layers, the isolated gate case is between at least one described first pixel region and described at least one Between a first pixel region and at least two second pixel region；It is corresponding at least one described first pixel region The first colour filter is formed on the antireflection layer, the corresponding antireflection layer of at least two second pixel region and it is described extremely The second colour filter is formed on few two burial lens；The first lenticule is formed on first colour filter, in second filter The second lenticule is formed on chromatograph, second lenticule is across at least two second pixel region.

In some embodiments of the present application, second colour filter is green or transparent.

In some embodiments of the present application, forming the method for burying lens on the antireflection layer includes: in the increasing It is formed in permeable layers and buries lens material layer；Photoresist layer is formed on the burial lens material layer；Pattern the photoresist Layer keeps the pattern of the photoresist layer consistent at least two burial figure of lens；Flow back the patterned photoetching Glue-line；Using the patterned photoresist layer as exposure mask, the burial lens material layer is etched, forms the burial lens；It goes Except the patterned photoresist layer.

A kind of phase-detection auto-focusing pixel element provided by the present application and forming method thereof, and include the phase The imaging sensor and forming method thereof of auto-focusing pixel element is detected, described image sensor includes that phase-detection is automatically right Burnt pixel element buries lens by being formed on the antireflection layer in the phase-detection auto-focusing pixel element, described to cover The light being injected into phase-detection auto-focusing pixel can further be assembled by burying lens, and it is automatic to increase the phase-detection The light-inletting quantity for pixel of focusing, increase when carrying out auto-focusing in the phase-detection auto-focusing pixel element pixel region it Between light intensity difference, increase the phase-detection auto-focusing pixel element to the response angle of light, improve focusing spirit Sensitivity.

Detailed description of the invention

Exemplary embodiment disclosed in this application is described in detail in the following drawings.Wherein identical appended drawing reference is in attached drawing Several views in indicate similar structure.Those of ordinary skill in the art will be understood that these embodiments be non-limiting, Exemplary embodiment, the purpose that attached drawing is merely to illustrate and describes, it is no intended to it limits the scope of the present disclosure, other modes Embodiment may also similarly complete the intention of the invention in the application.It should be appreciated that the drawings are not drawn to scale.Wherein:

Fig. 1 is a kind of structural schematic diagram of PDAF pixel in the prior art.

Fig. 2 to Fig. 9 is a kind of structural schematic diagram of each step of PDAF pixel element forming method in the embodiment of the present application.

Figure 10 to Figure 12 is a kind of structural schematic diagram of each step of imaging sensor forming method in the embodiment of the present application.

Distribution map of the Figure 13 for the pixel of imaging sensor a kind of in the embodiment of the present application in the semiconductor substrate.

Figure 14 is the opticpath figure that light enters PDAF pixel element from different perspectives.

Figure 15 is the opticpath figure in PDAF pixel element in the prior art.

Figure 16 is the opticpath figure in the present embodiment in PDAF pixel element.

Figure 17 is the relational graph in PDAF element between angle of light and light signal strength.

Specific embodiment

Following description provides the specific application scene of the application and requirements, it is therefore an objective to those skilled in the art be enable to make It makes and using the content in the application.To those skilled in the art, to the various partial modifications of the disclosed embodiments Be it will be apparent that and without departing from the spirit and scope of the disclosure, the General Principle that will can be defined here Applied to other embodiments and application.Therefore, the embodiment the present disclosure is not limited to shown in, but it is consistent most wide with claim Range.

Technical solution of the present invention is described in detail below with reference to embodiment and attached drawing.

The present embodiment provides a kind of forming method of phase-detection auto-focusing (hereinafter referred to as PDAF) pixel element, references Fig. 2 to Fig. 5, comprising: provide semiconductor substrate 110, the semiconductor substrate 110 includes at least two pixel regions 111；Institute State formation antireflection layer 140 in semiconductor substrate 110；At least two are formed on the antireflection layer 140 buries lens 170, it is described At least two, which bury 170 position of lens, corresponds at least two pixel region 111；In the antireflection layer 140 and described At least two bury formation colour filter 150 on lens 170, and the colour filter 150 covers described at least two and buries lens 170； Lenticule 160 is formed on the colour filter 150, the lenticule 160 is across at least two pixel region 111.

Fig. 2 to Fig. 9 is a kind of structural schematic diagram of each step of PDAF pixel element forming method in the embodiment of the present application.Under Face is described in further detail referring to figs. 2 to Fig. 9 PDAF pixel element forming method described in the embodiment of the present application.

With reference to Fig. 2, the semiconductor substrate 110 for being formed at least two photosensitive elements 120, the semiconductor substrate are provided 110 include at least two pixel regions 111, and at least two photosensitive element 120 corresponds respectively at least two pixel Region 111.For simplicity, two photosensitive elements 120 are only drawn in attached drawing 2 to 9 and two pixel regions 111 are used as and show Example.

In some embodiments of the present application, the semiconductor substrate 110 can be silicon substrate, or on insulator Silicon substrate, or growth has the silicon substrate of epitaxial layer.

In some embodiments of the present application, the semiconductor substrate 110 is P-type silicon, and the P-type silicon in silicon by serving as a contrast P-type doping is carried out in bottom realizes all doping to realize, such as using ion implanting or the technique of diffusion.Execute doping process When, the energy and doping concentration of Doped ions can be selected according to the prior art.

In some embodiments of the present application, the photosensitive element 120 is, for example, photodiode, for that will receive Optical signal be converted to electric signal.In order to meet the semiconductor substrate 110 overall thickness thinning requirement, described at least two Photodiode is located substantially on same depth in the semiconductor substrate 110.

In some embodiments of the present application, the photodiode can be held by passing through in semiconductor substrate 110 The ion implantation technology of row more than once is formed.The doping type of the photodiode is mixed with the semiconductor substrate 110 For miscellany type on the contrary, for example, when the semiconductor substrate 110 is that p-type is adulterated, the photodiode is n-type doping.

In some embodiments of the present application, the semiconductor substrate 110 may include at least two pixel regions 111, And at least two photosensitive element 120 identical at least two pixel regions, 111 quantity, at least two sense Optical element 120 corresponds respectively at least two pixel region 111.In some embodiments of the present application, the every two The phase-detection auto-focusing pixel element that pixel region 111 is formed constitutes a basic pixel unit.It is the multiple basic Pixel unit can be arranged in array.

With continued reference to Fig. 2, deep trench isolation structure 130, the deep trench isolation are formed in the semiconductor substrate 110 Structure 130 is between at least two pixel region 111, at least two pixel region 111 to be isolated, prevent into Penetrate light crosstalk between adjacent pixel regions 111.The formation process of the deep trench isolation structure 130 can be this field skill Any isolation technology that art personnel understand, is not described in detail herein.

With reference to Fig. 3, antireflection layer 140 is formed in the semiconductor substrate 110, the antireflection layer 140 can increase light Transmitance.In some embodiments of the present application, the method for forming the antireflection layer 140 is in the semiconductor substrate 110 Upper deposition antireflective material forms the antireflection layer 140.

In some embodiments of the present application, the antireflection layer 140 is the storehouse that one layer or more transparent dielectric material is formed Structure.

In some embodiments of the present application, the material for forming the antireflection layer 140 is fusing point at 300 degrees Celsius or more The transparent dielectric material of light penetration can be improved.Due to that may need to the semiconductor substrate 110 in the subsequent process It is heated, such as executes and be heated to reflux technique to form the burial lens 170, therefore the antireflection layer 140 needs one The fusing point of fixed heat-resisting ability, 140 material of antireflection layer will reach 300 degrees Celsius or more.

In some embodiments of the present application, the material of the antireflection layer 140 is aluminium oxide, hafnium oxide, zirconium oxide and nitrogen Any one or multiple material in SiClx it is compound.

With reference to Fig. 4 to Fig. 7, at least two are formed on the antireflection layer 140 and buries lens 170, described at least two cover 170 position of lens is buried corresponding at least two pixel region 111.Described at least two bury lens 170 can be by light Further assemble to the direction of the photosensitive element 120, increase the light-inletting quantity in the photosensitive element 120, increases progress certainly Light intensity difference when dynamic focusing between at least two photosensitive elements 120 described in the PDAF element increases the PDAF member Part improves focusing sensitivity to the response angle of light.

In some embodiments of the present application, the one side of the lens 170 far from the antireflection layer 140 of burying is curved surface, The curvature of the curved surface is bigger, and the burial lens 170 are stronger to the aggregate capabilities of light.

In some embodiments of the present application, the refractive index for forming the material for burying lens 170, which is greater than, forms colour filter The refractive index of the material of layer 150.The burial lens 170 and the refringence of the colour filter 150 are bigger, the burial lens The aggregate capabilities of 170 pairs of light are stronger.

In some embodiments of the present application, the width for burying lens 170 is at least two pixel region 111 3/4ths or more.

In some embodiments of the present application, at least two burial lens can be formed on the antireflection layer 140 170, it is described at least two bury lens 170 quantity it is identical as the quantity of at least two pixel region 111, it is described at least Two 170 positions of burial lens correspond at least two pixel region 111.

In some embodiments of the present application, described at least two materials for burying lens 170 are fusing point at 300 degrees Celsius Above transparent dielectric material.Due to that may need to add the semiconductor substrate 110 when forming the burial lens 170 Heat, therefore at least two burials lens 170 need certain heat-resisting ability, described at least two bury lens 170 Fusing point to reach 300 degrees Celsius or more.

In some embodiments of the present application, it is described at least two bury lens 170 material be silica, aluminium oxide, Hafnium oxide, zirconium oxide, any one in silicon nitride.

In some embodiments of the present application, at least two burial lens 170 are received with a thickness of 100 nanometers to 900 Rice.On the one hand described at least two thickness for burying lens 170 cannot be too high, cannot be to the whole high of the PDAF pixel element Degree has an impact；On the other hand described at least two thickness for burying lens 170 cannot be too low, otherwise will affect described at least two A light gathering for burying lens 170.

It with reference to Fig. 4, is formed on the antireflection layer 140 and buries lens material layer 171, the burial lens jacket 171 is used for Form the burial lens 170.

With continued reference to Fig. 4, spin coating photoresist forms photoresist layer 172 on the burial lens material layer 171.

With reference to Fig. 5, by exposing, develop, pattern the photoresist layer 172, make the pattern of the photoresist layer 172 with The figure of at least two burials lens 170 is consistent.

With reference to Fig. 6, flow back the patterned photoresist layer 172.In some embodiments of the present application, flow back the figure The temperature of the photoresist layer of case is 50 degrees Celsius to 150 degrees Celsius, and return time is 0.5 minute to 3 minutes.

With reference to Fig. 7, it is exposure mask with the patterned photoresist layer 172 after flowing back, etches the burial lens material Layer 171 forms the burial lens 170, and removes the patterned photoresist layer 172.

In some embodiments of the present application, etching the method for burying lens material layer 171 is, for example, dry etching.

With reference to Fig. 8, is buried in the antireflection layer 140 and described at least two and form colour filter 150, institute on lens 170 It states colour filter 150 and covers at least two burials lens 170.The colour filter 150 is used for the light by particular range of wavelengths, The light of the particular range of wavelengths is set to enter the photosensitive element 120.

In some embodiments of the present application, the colour filter 150 is formed with the internal resin added with organic pigment 's.The colour filter 150 is, for example, green or colourless.

With reference to Fig. 9, lenticule 160 is formed on the colour filter 150, the lenticule 160 is across described at least two Pixel region 111.The lenticule 160 for assembling light, material be, for example, polystyrene resin, acrylic resin or this What the copolymer resin of a little resins was formed.The technique for forming the lenticule 160 can be any one existing lenticule system Make technique, is not described in detail herein.

A kind of forming method of PDAF pixel element described in the embodiment of the present application, passes through the shape on the antireflection layer 140 At lens 170 are buried, light can further be assembled to the direction of the photosensitive element 120, be increased by the burial lens 170 Light-inletting quantity in the photosensitive element 120 increases two photosensitive elements described in PDAF element when carrying out auto-focusing Light intensity difference between 120 increases the PDAF element to the response angle of light, improves focusing sensitivity.

The embodiment of the present application also provides a kind of PDAF pixel elements, with reference to Fig. 9, comprising: semiconductor substrate 110, it is described Semiconductor substrate 110 includes at least two pixel regions 111；Antireflection layer 140, the antireflection layer 140 are located at semiconductor lining On bottom 110；At least two bury lens 170, and at least two burials lens 170 are located on the antireflection layer 140, position pair At least two pixel region 111 described in Ying Yu；Colour filter 150, the colour filter 150 is located on the antireflection layer 140, and covers It covers described at least two and buries lens 170；Lenticule 160 is located on the colour filter 150, across at least two pixel Region 111.

With reference to Fig. 9, at least two photosensitive elements 120 are formed in semiconductor substrate 110, the semiconductor substrate 110 is wrapped At least two pixel regions 111 are included, at least two photosensitive element 120 corresponds respectively at least two pixel region 111.For simplicity, two photosensitive elements 120 and two pixel regions 111 are only drawn in attached drawing 9 as example.

It is described in reference diagram 9, be formed with deep trench isolation structure 130 in the semiconductor substrate 110, the deep trench every From structure 130 between at least two pixel region 111, at least two pixel region 111 to be isolated, prevent Incident ray crosstalk between adjacent pixel regions 111.The formation process of the deep trench isolation structure 130 can be this field Any isolation technology that technical staff understands, is not described in detail herein.

It is described in reference diagram 9, antireflection layer 140 is formed in the semiconductor substrate 110, the antireflection layer 140 can increase Add the transmitance of light.In some embodiments of the present application, the method for forming the antireflection layer 140 is to serve as a contrast in the semiconductor Antireflective material is deposited on bottom 110 forms the antireflection layer 140.

In some embodiments of the present application, the material for forming the antireflection layer 140 is fusing point at 300 degrees Celsius or more The transparent dielectric material of light penetration can be improved.Due to needs pair possible in the technique for forming the PDAF pixel element The semiconductor substrate 110 is heated, such as is executed and be heated to reflux technique to form the burial lens 170, therefore is described Antireflection layer 140 needs certain heat-resisting ability, and the fusing point of the antireflection layer 140 will reach 300 degrees Celsius or more.

In some embodiments of the present application, 140 material of antireflection layer is aluminium oxide, hafnium oxide, zirconium oxide and nitridation Any one or multiple material in silicon it is compound.

It is described in reference diagram 9, at least two burial lens 170 are formed on the antireflection layer 140, described at least two cover 170 position of lens is buried corresponding at least two pixel region 111.Described at least two bury lens 170 can be by light Further assemble to the direction of at least two photosensitive element 120, increases the entering light at least two photosensitive element 120 Amount increases light intensity difference when carrying out auto-focusing between at least two photosensitive elements 120 described in the PDAF element, increases The big PDAF element improves focusing sensitivity to the response angle of light.

Refering to what is shown in Fig. 9, being formed with colour filter on the antireflection layer 140 and at least two burials lens 170 150, the colour filter 150 covers described at least two and buries lens 170.The colour filter 150 is used to pass through specific wavelength model The light enclosed makes the light of the particular range of wavelengths enter the photosensitive element 120.

In some embodiments of the present application, the colour filter 150 is formed with the internal resin added with organic pigment 's.The colour filter 150 is, for example, green or transparent.

Refering to what is shown in Fig. 9, be also formed with lenticule 160 on the colour filter 150, the lenticule 160 is across described At least two pixel regions 111.For the lenticule 160 for assembling light, material is, for example, polystyrene resin, acrylic acid What the copolymer resin of resin or these resins was formed.Formed the lenticule 160 technique can be it is existing any one Lenticule manufacture craft, is not described in detail herein.

PDAF pixel element described in the embodiment of the present application, it is saturating on the antireflection layer 140 to be formed at least two burials Mirror 170, described at least two bury lens 170 can be further by light to the direction of at least two photosensitive element 120 Aggregation increases the light-inletting quantity at least two photosensitive element 120, increases when carrying out auto-focusing in the PDAF element Light intensity difference between at least two photosensitive element 120 increases the PDAF element to the response angle of light, improves Focusing sensitivity.

The embodiment of the present application also provides a kind of forming method of imaging sensor, comprising: provides semiconductor substrate 110, institute State semiconductor substrate 110 include at least one first pixel region 201 and at least two second pixel regions 202, described second Pixel region 202 is used to form PDAF pixel element；Antireflection layer 140 is formed in the semiconductor substrate 110；Described anti-reflection At least two are formed on layer 140 and buries lens 170, and described at least two, which bury 170 position of lens, corresponds to second pixel Region 202；On the antireflection layer 140 formed isolation grid 210, the isolation grid 210 be located at described at least one first Between pixel region 201 and described at least one first pixel region 201 and at least two second pixel region 202 it Between；The first colour filter 151 is formed at least one described corresponding described antireflection layer 140 of the first pixel region 201, described Second is formed on the corresponding antireflection layer 140 of at least two second pixel region 202 and at least two burials lens 170 Colour filter 152；The first lenticule 161 is formed on first colour filter 151, and is formed on second colour filter 152 Two lenticules 162, second lenticule 162 is across at least two second pixel region 202.

Figure 10 to Figure 12 is a kind of structural schematic diagram of each step of imaging sensor forming method in the embodiment of the present application.Under Face is described in further detail with reference to figures 10 to Figure 12 imaging sensor forming method described in the embodiment of the present application.

With reference to Figure 10, the semiconductor substrate 110 for being formed with photosensitive element 120 is provided, the semiconductor substrate 110 includes extremely Few first pixel region 201 and at least two second pixel regions 202, wherein at least one described first pixel region 201 are used to form imaging pixel, and at least two second pixel region 202 is used to form PDAF pixel element, described photosensitive Element 120 corresponds respectively to different pixel regions.

In some embodiments of the present application, the photosensitive element 120 is, for example, photodiode, for that will receive Optical signal be converted to electric signal.In some embodiments of the present application, the photodiode in semiconductor substrate 110 with Bayer (Bayer) array arrangement.In order to meet the semiconductor substrate 110 overall thickness thinning requirement, two pole of photoelectricity Pipe is located substantially on same depth in the semiconductor substrate 110.

Continue to refer to figure 10, in the semiconductor substrate 110 formed deep trench isolation structure 130, the deep trench every From structure 130 for preventing incident ray crosstalk between adjacent pixel regions 111.The shape of the deep trench isolation structure 130 Can be at technique skilled in the art realises that any isolation technology, be not described in detail herein.

Refering to what is shown in Fig. 10, forming antireflection layer 140 in the semiconductor substrate 110, the antireflection layer 140 can increase The transmitance of light.In some embodiments of the present application, the method for forming the antireflection layer 140 is in the semiconductor substrate Antireflective material is deposited on 110 forms the antireflection layer 140.

In some embodiments of the present application, the material for forming the antireflection layer 140 is fusing point at 300 degrees Celsius or more The transparent dielectric material of light penetration can be improved.Due to that may need to the semiconductor substrate 110 in the subsequent process It is heated, such as executes and be heated to reflux technique to form the burial lens 170, therefore the antireflection layer 140 needs one The fusing point of fixed heat-resisting ability, the antireflection layer 140 will reach 300 degrees Celsius or more.

In some embodiments of the present application, the antireflection layer 140 is in aluminium oxide, hafnium oxide, zirconium oxide and silicon nitride Any one or multiple material composite layer.

With reference to Figure 11, at least two are formed on the antireflection layer 140 and buries lens 170, described at least two bury thoroughly 170 position of mirror corresponds at least two second pixel region 202.Form described at least two methods for burying lens 170 It has been described in above, this will not be repeated here.Described at least two bury lens 170 can be by light further to institute The direction aggregation for stating at least two photosensitive elements 120, increases the light-inletting quantity at least two photosensitive element 120, increases Light intensity difference when auto-focusing between at least two photosensitive elements 120 described in the PDAF element is carried out, is increased described PDAF element improves focusing sensitivity to the response angle of light.

In some embodiments of the present application, the width for burying lens 170 is at least two second pixel region 3/4ths or more of domain 202.

In some embodiments of the present application, at least two burial lens can be formed on the antireflection layer 140 170, the quantity of at least two burials lens 170 is identical as the quantity of at least two second pixel region 202, described At least two, which bury 170 position of lens, corresponds at least two second pixel region 202.

With reference to Figure 11, form isolation grid 210 on the antireflection layer 140, the isolation grid 210 be located at described at least Between one the first pixel region 201 and at least one described first pixel region 201 and at least two second pixel Between region 202.The isolation grid 210 can prevent the light of at least one first pixel region 201 from entering other First pixel region 201 and the second pixel region 202.

With reference to Figure 12, the first filter is formed at least one described corresponding described antireflection layer 140 of the first pixel region 201 Chromatograph 151 is buried saturating in the corresponding antireflection layer 140 of at least two second pixel region 202 and described at least two The second colour filter 152 is formed on mirror 170.First colour filter 151 and the second colour filter 152 are used to pass through specific wavelength model The light enclosed makes the light of the particular range of wavelengths enter the photosensitive element 120.

In some embodiments of the present application, as needed, first colour filter 151 can be set to make red light By or make blue light pass through.

In some embodiments of the present application, can be set to make in second colour filter 152 light of green pass through or Person passes through whole light.

In some embodiments of the present application, the colour filter 151 and the second colour filter 152 are that have with inside What the resin of machine pigment was formed.In some embodiments of the present application, when second colour filter 152 be arranged to make it is whole When light passes through, second colour filter 152 can be formed with transparent medium.

With reference to shown in Figure 12, the first lenticule 161 is formed on first colour filter 151, in second colour filter The second lenticule 162 is formed on 152, second lenticule 162 is across at least two second pixel region 202.It is described The first lenticule 161 and the second lenticule 162 for assembling light, material is, for example, polystyrene resin, acrylic acid tree What the copolymer resin of rouge or these resins was formed.The technique for forming first lenticule 161 and the second lenticule 162 can To be any one existing lenticule manufacture craft, it is not described in detail herein.

A kind of forming method of imaging sensor described in the embodiment of the present application, at least two second pixel region 202 form PDAF pixel element, form at least two on the corresponding antireflection layer 140 of the PDAF pixel element and bury lens 170, at least two burials lens 170 can further gather light to the direction of at least two photosensitive element 120 Collection increases the light-inletting quantity at least two photosensitive element 120, increases PDAF pixel element when carrying out auto-focusing Described in light intensity difference between at least two photosensitive elements 120, increase the PDAF element to the response angle of light, mention High focusing sensitivity.

The embodiment of the present application also provides a kind of imaging sensor, with reference to Figure 12, comprising: semiconductor substrate 110, it is described partly to lead Body substrate 110 includes at least one first pixel region 201 and at least two second pixel regions 202, second pixel region Domain 202 is used to form PDAF pixel element；Antireflection layer 140 is located in the semiconductor substrate 110；At least two bury lens 170, it is located on the antireflection layer 140, position is corresponding with second pixel region 202；First colour filter 151 and the second filter Chromatograph 152 is located on the antireflection layer 140, the position of first colour filter 151 and at least one described first pixel region 201 is corresponding, and the position of second colour filter 152 is covered at least two second pixel region 202 and described at least two It is corresponding to bury lens 170；Grid 210 is isolated, is located on the antireflection layer 140, and first colour filter of arbitrary neighborhood is isolated 151 and second colour filter 152；First lenticule 161 and the second lenticule 162, first lenticule 161 are located at described the On one colour filter 151, second lenticule 162 is located on second colour filter 152, second lenticule 162 across At least two second pixel region 202.

With reference to Figure 12, photosensitive element 120 is formed in the semiconductor substrate 110, the semiconductor substrate 110 includes extremely Few first pixel region 201 and at least two second pixel regions 202, wherein at least one described first pixel region 201 are used to form imaging pixel, and at least two second pixel region 202 is used to form PDAF pixel element, described photosensitive Element 120 corresponds respectively to different pixel regions.

2 are continued to refer to figure 1, deep trench isolation structure 130, the deep trench are formed in the semiconductor substrate 110 Isolation structure 130 is for preventing incident ray crosstalk between adjacent pixel regions 111.The deep trench isolation structure 130 Formation process can be skilled in the art realises that any isolation technology, be not described in detail herein.

With reference to shown in Figure 12, antireflection layer 140 is formed in the semiconductor substrate 110, the antireflection layer 140 can increase Add the transmitance of light.

With reference to Figure 12, at least two burial lens 170 are formed on the antireflection layer 140, described at least two bury 170 position of lens corresponds at least two pixel region 111.It is described at least two bury lens 170 can by light into One step is assembled to the direction of at least two photosensitive element 120, increases the entering light at least two photosensitive element 120 Amount increases light intensity difference when carrying out auto-focusing between at least two photosensitive elements 120 described in the PDAF element, increases The big PDAF element improves focusing sensitivity to the response angle of light.

In some embodiments of the present application, described at least two materials for burying lens 170 are fusing point at 300 degrees Celsius Above transparent dielectric material.Due to that may need when forming at least two burials lens 170 to the semiconductor substrate 110 are heated, therefore at least two burials lens 170 need certain heat-resisting ability, and described at least two cover The fusing point for burying lens 170 will reach 300 degrees Celsius or more.

With reference to shown in Figure 12, isolation grid 210 is formed on the antireflection layer 140, the isolation grid 210 is located at institute It states between at least one first pixel region 201 and at least one described first pixel region 201 and described at least two the Between two pixel regions 202.The isolation grid 210 can prevent the light of at least one first pixel region 201 into Enter other first pixel regions 201 and the second pixel region 202.

With reference to shown in Figure 12, is formed at least one described corresponding described antireflection layer 140 of the first pixel region 201 One colour filter 151 is covered in the corresponding antireflection layer 140 of at least two second pixel region 202 and described at least two It buries and forms the second colour filter 152 on lens 170.First colour filter 151 and the second colour filter 152 are for passing through certain wave The light of long range makes the light of the particular range of wavelengths enter the photosensitive element 120.

With reference to shown in Figure 12, the first lenticule 161 is formed on first colour filter 151, in second colour filter The second lenticule 162 is formed on 152, second lenticule 162 is across at least two second pixel region 202.It is described The first lenticule 161 and the second lenticule 162 for assembling light, material is, for example, polystyrene resin, acrylic acid tree What the copolymer resin of rouge or these resins was formed.

A kind of imaging sensor described in the embodiment of the present application is formed at least two second pixel region 202 PDAF pixel element is formed at least two burial lens 170, institute on the corresponding antireflection layer 140 of the PDAF pixel element Stating at least two burial lens 170 can further assemble light to the direction of at least two photosensitive element 120, increase Light-inletting quantity at least two photosensitive element 120 increases when carrying out auto-focusing described in the PDAF pixel element Light intensity difference between at least two photosensitive elements 120 increases the PDAF element to the response angle of light, improves pair Burnt sensitivity.

Distribution map of the Figure 13 for the pixel of imaging sensor a kind of in the embodiment of the present application in the semiconductor substrate.With reference to figure 13, at least two second pixel region 202 (i.e. PDAF pixel element) is symmetrical in the semiconductor substrate 110, When described image sensor gets the image of object, by detecting the photosensitive element 120 in symmetrical PDAF pixel element The light intensity difference received, then pass through the location information of the available object of algorithm process, to instruct the back-and-forth motion of camera lens Realize auto-focusing.

It, can be only right in the part of imaging sensor second pixel region 202 in some embodiments of the present application Described at least two are formed on the antireflection layer 140 answered and buries lens 170, without being used in the second all pixel regions 202 all It forms described at least two and buries lens 170, also can achieve the effect of raising focusing sensitivity described in the present embodiment.

Figure 14 is the opticpath figure that light enters PDAF pixel element from different perspectives.Wherein, the PDAF pixel elements Part includes pixel 1 and pixel 2.Light when the angle shown in Figure 14 (a) of light 300 enters imaging sensor, in pixel 1 Line intensity is greater than the light intensity in pixel 2；When the angle shown in Figure 14 (b) of light 300 enters imaging sensor, as Light intensity in element 1 is equal to the light intensity in pixel 2；It is passed when the angle shown in Figure 14 (c) of light 300 enters image When sensor, the light intensity in pixel 1 is less than the light intensity in pixel 2.Therefore, to master angle of incidence of light and pixel 1 and pixel 2 in light intensity difference between relationship, so that it may be calculated after obtaining the light intensity difference in pixel 1 and pixel 2 Angle of incidence of light.

In conjunction with Figure 13 and Figure 14, according to the light between the pixel 1 and pixel 2 in symmetrical all PDAF pixel elements Strong difference is calculated the angle of incidence of light of each PDAF pixel element, can be obtained by object according to angle of incidence of light Location information to instruct camera lens back-and-forth motion realize auto-focusing.

The embodiment of the present application also passes through opticpath figure and existing skill in comparison the present embodiment in PDAF pixel element Opticpath figure in art in PDAF pixel element comes more intuitive the advantages of more clearly explaining the application and beneficial effect.

Figure 15 is the opticpath figure in PDAF pixel element in the prior art, and Figure 16 is PDAF pixel elements in the present embodiment Opticpath figure in part.Comparison diagram 15 and Figure 16, compared with PDAF pixel element in the prior art, the embodiment of the present application Described at least two in the PDAF pixel element, which bury lens 170, further to feel light to described at least two The direction of optical element 120 is assembled, and is increased the light-inletting quantity at least two photosensitive element 120, is increased carry out auto-focusing Light intensity difference between at least two photosensitive elements 120 described in Shi Suoshu PDAF pixel element increases the PDAF element To the response angle of light, focusing sensitivity is improved.

Figure 17 is the relational graph in PDAF element between angle of light and light signal strength.Wherein, curve 11 and curve 12 respectively represent angle of incident light and light signal strength in pixel 1 described in herein described PDAF pixel element and pixel 2 Between relationship；Curve 21 and curve 22 respectively represent incident light in pixel 1 described in traditional PDAF pixel element and pixel 2 Relationship between line angle degree and light signal strength.At least two described in the PDAF pixel element as described in the embodiment of the present application A lens 170 of burying act on the convergence of incident ray, light from same angle enter PDAF pixel element when It waits, the light intensity difference between the pixel 1 and pixel 2 in PDAF pixel element described in the embodiment of the present application becomes apparent, and increases The big PDAF element improves focusing sensitivity to the response angle of light.

In conclusion after reading this detailed disclosures, it will be understood by those skilled in the art that aforementioned detailed disclosure Content can be only presented in an illustrative manner, and can not be restrictive.Although not explicitly described or shown herein, this field skill Art personnel are understood that improve and modify it is intended to include the various reasonable changes to embodiment.These change, improve and It modifies and is intended to be proposed by the disclosure, and in the spirit and scope of the exemplary embodiment of the disclosure.

It should be appreciated that term that the present embodiment uses " and/or " it include associated listing one or more of project It is any or all combination.It, can be with it should be appreciated that when an element is referred to as " connection " or " coupling " to another element It is directly connected or is coupled to another element, or there may also be intermediary elements.

Similarly, it should be understood that when the element of such as layer, region or substrate etc is referred to as in another element " upper " When, it can directly on the other element, or there may also be intermediary elements.In contrast, term " directly " indicates There is no intermediary element.It is also understood that term " including ", " including ", " include " and/or " including ", herein in use, referring to Bright there are documented feature, entirety, step, operation, element and/or component, but presence or one or more additional is not precluded Other a features, entirety, step, operation, element, component and/or their group.

It is also understood that although term first, second, third, etc. can be used herein to describe various elements, these Element should not be limited by these terms.These terms are only used to distinguish an element with another element.Therefore, exist In the case where not being detached from the teachings of the present invention, first element in some embodiments can be referred to as in other embodiments Second element.Identical reference label or identical reference designator indicate identical element throughout the specification.

In addition, by reference to as Utopian graphical representation of exemplary cross sectional view and/or plane diagram example is described Property embodiment.Therefore, because with the shape illustrated not being both foreseeable caused by such as manufacturing technology and/or tolerance.Cause Exemplary embodiment, should not be interpreted as being limited to the shape in region out shown here, but should include by for example making by this The deviation in shape caused by making.For example, the etching area for being shown as rectangle would generally have circular or curved spy Sign.Therefore, region shown in figure is substantially schematical, and shape is not configured to show the practical shape in the region of device Shape is also not to limit the range of exemplary embodiment.

In addition, embodiment of the present disclosure can also include following exemplary example (EE).

EE1. a kind of phase-detection auto-focusing pixel element, comprising:

Semiconductor substrate, the semiconductor substrate include at least two pixel regions；

Antireflection layer, the antireflection layer are located in the semiconductor substrate；

At least two bury lens, and at least two burials lens are located on the antireflection layer, and position corresponds to described At least two pixel regions；

Colour filter, the colour filter are located on the antireflection layer, and cover described at least two and bury lens；

Lenticule is located on the colour filter, across at least two pixel region.

EE2. the phase-detection auto-focusing pixel element as described in EE1, which is characterized in that described at least two bury lens Material be transparent dielectric material of the fusing point at 300 degrees Celsius or more.

EE3. the phase-detection auto-focusing pixel element as described in EE2, which is characterized in that described at least two bury lens Material be silica, aluminium oxide, hafnium oxide, zirconium oxide, any one in silicon nitride.

EE4. the phase-detection auto-focusing pixel element as described in EE1, which is characterized in that described at least two bury lens With a thickness of 100 nanometers to 900 nanometers.

EE5. the phase-detection auto-focusing pixel element as described in EE1, which is characterized in that the anti-reflection layer material is fusing point In 300 degrees Celsius or more of the transparent dielectric material that light penetration can be improved.

EE6. the phase-detection auto-focusing pixel element as described in EE5, which is characterized in that the anti-reflection layer material is oxidation Aluminium, hafnium oxide, zirconium oxide, in silicon nitride any one or it is a variety of.

EE7. the phase-detection auto-focusing pixel element as described in EE6, which is characterized in that the antireflection layer is one layer or more The stack architecture that the transparent dielectric material is formed.

EE8. a kind of forming method of phase-detection auto-focusing pixel element, comprising:

Semiconductor substrate is provided, the semiconductor substrate includes at least two pixel regions；

Antireflection layer is formed on the semiconductor substrate；

At least two are formed on the antireflection layer and buries lens, and described at least two bury lens position corresponding to described At least two pixel regions；

Colour filter is formed on the antireflection layer and at least two burials lens, the colour filter covering is described extremely Few two burial lens；

Lenticule is formed on the colour filter, the lenticule is across at least two pixel region.

EE9. as described in EE8 phase-detection auto-focusing pixel element forming method, which is characterized in that described at least two A material for burying lens is transparent dielectric material of the fusing point at 300 degrees Celsius or more.

EE10. as described in EE9 phase-detection auto-focusing pixel element forming method, which is characterized in that it is described at least The material of two burial lens is silica, aluminium oxide, hafnium oxide, zirconium oxide, any one in silicon nitride.

EE11. as described in EE8 phase-detection auto-focusing pixel element forming method, which is characterized in that it is described at least Two burial lens with a thickness of 100 nanometers to 900 nanometers.

EE12. as described in EE8 phase-detection auto-focusing pixel element forming method, which is characterized in that it is described anti-reflection Layer material is the transparent dielectric material that can be improved light penetration of the fusing point at 300 degrees Celsius or more.

EE13. as described in EE12 phase-detection auto-focusing pixel element forming method, which is characterized in that it is described anti-reflection Layer material be aluminium oxide, hafnium oxide, zirconium oxide and silicon nitride in any one or it is a variety of.

EE14. as described in EE13 phase-detection auto-focusing pixel element forming method, which is characterized in that it is described anti-reflection The stack architecture that layer is formed for one layer of transparent dielectric material described above.

EE15. as described in EE8 phase-detection auto-focusing pixel element forming method, which is characterized in that in the increasing The method that at least two bury lens is formed in permeable layers includes:

It is formed on the antireflection layer and buries lens material layer；

Photoresist layer is formed on the burial lens material layer；

The photoresist layer is patterned, the pattern of the photoresist layer and the figure one of at least two burials lens are made It causes；

Flow back the patterned photoresist layer；

Using the patterned photoresist layer as exposure mask, the burial lens material layer is etched, forms the burial lens；

Remove the patterned photoresist layer.

EE16. as described in EE15 phase-detection auto-focusing pixel element forming method, which is characterized in that described in reflux The temperature of patterned photoresist layer is 50 degrees Celsius to 150 degrees Celsius, and return time is 0.5 minute to 3 minutes.

EE17. a kind of imaging sensor, comprising:

Semiconductor substrate, the semiconductor substrate include at least one first pixel region and at least two second pixel regions Domain, second pixel region are used to form phase-detection auto-focusing pixel element；

Antireflection layer is located in the semiconductor substrate；

At least two bury lens, are located on the antireflection layer, position is corresponding with second pixel region；

First colour filter and the second colour filter, be located at the antireflection layer on, the position of first colour filter with it is described At least one first pixel region is corresponding, the position of second colour filter and at least two second pixel region and described At least two, which bury lens, corresponds to；

Grid is isolated, is located on the antireflection layer, and first colour filter and the second colour filter of arbitrary neighborhood is isolated；

First lenticule and the second lenticule, first lenticule are located on first colour filter, and described second Lenticule is located on second colour filter, and second lenticule is across at least two second pixel region.

EE18. a kind of forming method of imaging sensor, comprising:

Semiconductor substrate is provided, the semiconductor substrate includes at least one first pixel region and at least two second pictures Plain region, second pixel region are used to form phase-detection auto-focusing pixel element；

Antireflection layer is formed on the semiconductor substrate；

At least two are formed on the antireflection layer and buries lens, and described at least two bury lens position corresponding to described Second pixel region；

On the antireflection layer formed isolation grid, the isolated gate case at least one described first pixel region it Between and at least one described first pixel region and at least two second pixel region between；

Form the first colour filter on the corresponding antireflection layer of at least one described first pixel region, it is described at least The second colour filter is formed on the corresponding antireflection layer of two the second pixel regions and at least two burials lens；

The first lenticule is formed on first colour filter, forms the second lenticule, institute on second colour filter The second lenticule is stated across at least two second pixel region.

EE19. as EE18 described image sensor forming method, which is characterized in that second colour filter be green or Person is transparent.

EE20. such as the forming method of EE19 described image sensor, which is characterized in that formed and buried on the antireflection layer The method of lens includes:

It is formed on the antireflection layer and buries lens material layer；

Photoresist layer is formed on the burial lens material layer；

Flow back the patterned photoresist layer；

Remove the patterned photoresist layer.

Claims

1. a kind of phase-detection auto-focusing pixel element, comprising:

At least two bury lens, it is described at least two burial lens is located on the antireflection layer, position correspond to described at least Two pixel regions；

Lenticule is located on the colour filter, across at least two pixel region.

2. phase-detection auto-focusing pixel element as described in claim 1, which is characterized in that described at least two bury lens Material be transparent dielectric material of the fusing point at 300 degrees Celsius or more.

3. phase-detection auto-focusing pixel element as described in claim 1, which is characterized in that described at least two bury lens With a thickness of 100 nanometers to 900 nanometers.

4. a kind of forming method of phase-detection auto-focusing pixel element, comprising:

Antireflection layer is formed on the semiconductor substrate；

Form at least two on the antireflection layer and bury lens, described at least two bury lens position correspond to it is described at least Two pixel regions；

Colour filter, the colour filter covering described at least two are formed on the antireflection layer and at least two burials lens A burial lens；

5. the forming method of phase-detection auto-focusing pixel element as claimed in claim 4, which is characterized in that described at least two A material for burying lens is transparent dielectric material of the fusing point at 300 degrees Celsius or more.

6. the forming method of phase-detection auto-focusing pixel element as claimed in claim 4, which is characterized in that described at least two It is a bury lens with a thickness of 100 nanometers to 900 nanometers.

7. the forming method of phase-detection auto-focusing pixel element as claimed in claim 4, which is characterized in that described anti-reflection The method that at least two bury lens is formed on layer includes:

It is formed on the antireflection layer and buries lens material layer；

Photoresist layer is formed on the burial lens material layer；

The photoresist layer is patterned, keeps the pattern of the photoresist layer consistent at least two burial figure of lens；

Flow back the patterned photoresist layer；

Remove the patterned photoresist layer.

8. a kind of imaging sensor, comprising:

Semiconductor substrate, the semiconductor substrate include at least one first pixel region and at least two second pixel regions, Second pixel region is used to form phase-detection auto-focusing pixel element；

Antireflection layer is located in the semiconductor substrate；

First colour filter and the second colour filter, be located at the antireflection layer on, the position of first colour filter and it is described at least One the first pixel region is corresponding, the position of second colour filter and at least two second pixel region and it is described at least Two burial lens are corresponding；

First lenticule and the second lenticule, first lenticule are located on first colour filter, and described second is micro- Mirror is located on second colour filter, and second lenticule is across at least two second pixel region.

9. a kind of forming method of imaging sensor, comprising:

Semiconductor substrate is provided, the semiconductor substrate includes at least one first pixel region and at least two second pixel regions Domain, second pixel region are used to form phase-detection auto-focusing pixel element；

Antireflection layer is formed on the semiconductor substrate；

At least two are formed on the antireflection layer and buries lens, and described at least two, which bury lens position, corresponds to described second Pixel region；

On the antireflection layer formed isolation grid, the isolated gate case between at least one described first pixel region with And between at least one described first pixel region and at least two second pixel region；

The first colour filter is formed on the corresponding antireflection layer of at least one described first pixel region, described at least two The second colour filter is formed on the corresponding antireflection layer of second pixel region and at least two burials lens；

The first lenticule is formed on first colour filter, forms the second lenticule on second colour filter, described Two lenticules are across at least two second pixel region.

10. the forming method of imaging sensor as claimed in claim 9, which is characterized in that formed and buried on the antireflection layer The method of lens includes:

It is formed on the antireflection layer and buries lens material layer；

Photoresist layer is formed on the burial lens material layer；

Flow back the patterned photoresist layer；

Remove the patterned photoresist layer.