WO2020199142A1 - 光学准直器及其制作方法 - Google Patents

光学准直器及其制作方法 Download PDF

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Publication number
WO2020199142A1
WO2020199142A1 PCT/CN2019/081153 CN2019081153W WO2020199142A1 WO 2020199142 A1 WO2020199142 A1 WO 2020199142A1 CN 2019081153 W CN2019081153 W CN 2019081153W WO 2020199142 A1 WO2020199142 A1 WO 2020199142A1
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WIPO (PCT)
Prior art keywords
collimator
sub
hole
metal layer
collimating
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PCT/CN2019/081153
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English (en)
French (fr)
Inventor
姚国峰
沈健
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深圳市汇顶科技股份有限公司
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Application filed by 深圳市汇顶科技股份有限公司 filed Critical 深圳市汇顶科技股份有限公司
Priority to PCT/CN2019/081153 priority Critical patent/WO2020199142A1/zh
Priority to CN201980002372.9A priority patent/CN110770639B/zh
Publication of WO2020199142A1 publication Critical patent/WO2020199142A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/30—Collimators
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1324—Sensors therefor by using geometrical optics, e.g. using prisms

Definitions

  • This application relates to the field of optical devices, in particular to optical collimators and manufacturing methods thereof.
  • under-screen fingerprint recognition can generally be divided into three types: optical, ultrasonic, and capacitive.
  • optical fingerprint recognition module a collimator is usually provided for guiding the reflected light reflected from the surface of the finger to the image sensor below for optical detection.
  • the collimator can be a separate optical component (discrete) or integrated in the image sensor (integrated).
  • the advantage of the discrete collimator is that it can obtain a high aspect ratio, such as a through silicon via (Through Silicon Via, TSV) process, but its disadvantage is that the cost is relatively high.
  • the integrated collimator is based on the metal layer in the complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) back-end process.
  • CMOS complementary Metal Oxide Semiconductor
  • the present application provides an optical collimator and a manufacturing method thereof, which can increase the aspect ratio of the optical collimator, and further improve its spatial filtering ability for light.
  • an optical collimator in a first aspect, includes: 2N-1 sub-collimators, N is a positive integer greater than 1, wherein the first metal layer is provided with a collimating hole to form The first sub-collimator of the 2N-1 sub-collimators; the second metal layer is provided with a collimating hole to form the third sub-collimator of the 2N-1 sub-collimators, the second The metal layer is located above the first metal layer; between the i-1th metal layer and the i-th metal layer is the i-1th through hole layer, and the i-1th through hole is provided in the i-1th through hole layer, The i-1 th through hole filled with metal is used to connect the i-1 th metal layer and the i th metal layer, and the i-1 th through hole layer is the 2i-2 th in the 2N-1 sub-collimator Sub-collimators, i take 2, 3,...N in sequence; the i-th metal layer is provided with a collim
  • the first sub-collimator to the 2n-1th sub-collimator in the 2N-1 sub-collimators satisfy: the first sub-collimator
  • the collimating hole diameter of the collimator is the minimum value of the collimating hole diameter of the 2N-1 sub-collimators
  • the first sub-collimator to the 2n-1th sub-collimator are formed on the metal layer
  • the collimating holes of the sub-collimators have the same shape and the same apertures, n is a positive integer, 2 ⁇ n ⁇ N, the central axis of the collimating holes of the 2j-3th sub-collimator is with the 2j-1th sub-collimator
  • the offset direction between the central axes of the collimator holes of the straightener is a preset direction and the offset distance is a preset value, j is a positive integer, and j is 2, 3,...n in turn.
  • the collimating holes of the first sub-collimator to the 2n-1th sub-collimator have the same shape.
  • the preset value is zero.
  • n N.
  • the collimating hole diameters of the 2N-1 sub-collimators are equal.
  • the preset value is greater than zero.
  • the central axis of the collimation hole of the 2j-3th sub-collimator is aligned with the alignment of the 2j-2th sub-collimator
  • the offset direction between the central axes of the holes is the preset direction, and the offset distance is half of the preset value.
  • the material of the first metal layer and the i-th metal layer is at least one of the following materials: aluminum, copper, and nitride titanium.
  • the material of the metal filled in the via hole in the i-1 th via hole layer is tungsten and/or copper.
  • the filling material in the collimating hole of the optical collimator is silicon dioxide and/or silicon nitride.
  • the optical collimator according to the embodiment of the present application is provided with multiple metal layers to form an optical collimator composed of multiple sub-collimators, which can solve the problem that the aspect ratio of the existing integrated collimator is difficult to improve , Which effectively increases the aspect ratio, thereby improving its spatial filtering capacity.
  • a method for manufacturing an optical collimator includes: providing a collimating hole on a first metal layer to form a first sub-collimator; and providing a collimator on the second metal layer. Hole to form a third sub-collimator, the second metal layer is located above the first metal layer; the i-1 th through hole layer is arranged between the i-1 th metal layer and the i th metal layer.
  • the i-1 th through hole layer is the 2i-2 th sub-collimation , I take 2, 3,...N in turn, and N is a positive integer greater than 1.
  • a collimating hole is provided on the i-th metal layer to form the 2i-1th sub-collimator, and the i-th metal layer is located Above the i-1th metal layer.
  • the first to the 2n-1th sub-collimators of the 2N-1 sub-collimators of the optical collimator satisfy:
  • the collimating hole diameter of the first sub-collimator is the minimum value of the collimating hole diameters of the 2N-1 sub-collimators, and between the first sub-collimator and the 2n-1 sub-collimator
  • the collimating holes of the sub-collimators formed on the metal layer have the same shape and the same apertures, n is a positive integer, 2 ⁇ n ⁇ N, and the central axis of the collimating holes of the 2j-3th sub-collimator and the first
  • the offset direction between the central axes of the collimating holes of the 2j-1 sub-collimators is a preset direction and the offset distance is a preset value, j is a positive integer, and j is 2, 3, ... n in turn.
  • the shapes of the collimating holes from the first sub-collimator to the 2n ⁇ 1th sub-collimator are the same.
  • the preset value is zero.
  • n N.
  • the collimating hole diameters of the 2N-1 sub-collimators are equal.
  • the preset value is greater than zero.
  • the central axis of the collimating hole of the 2j-3th sub-collimator is aligned with the alignment of the 2j-2th sub-collimator
  • the offset direction between the central axes of the holes is the preset direction, and the offset distance is half of the preset value.
  • an optical fingerprint recognition module including: the optical collimator and the image sensor in the first aspect or any possible implementation of the first aspect, the image sensor is arranged in the optical collimator Below the optical collimator, the optical collimator is used to filter the return light reflected by the finger and converge to the image sensor; the image sensor is used to receive the return light passing through the optical collimator and generate the return light according to the received return light Fingerprint data, which is used for fingerprint identification of the finger.
  • the optical fingerprint recognition module further includes: a light source for generating light, the light for illuminating the finger and reflecting to generate the return light.
  • a terminal device including: a display screen for providing a touch interface for a finger; the optical fingerprint identification module in the third aspect or any possible implementation of the third aspect is located on the display screen Below, it is used to fingerprint the finger.
  • the display screen includes: light-emitting display pixels for displaying images and emitting light, and the light is used to illuminate the finger and reflect the returning light.
  • Fig. 1 is a schematic diagram of the principle of an optical under-screen fingerprint recognition technology based on a collimator according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of the angle of light in the collimating hole of the collimator according to the embodiment of the present application.
  • Fig. 3 is a cross-sectional view of an optical collimator according to an embodiment of the present application.
  • Fig. 4 is a top view of an optical collimator according to an embodiment of the present application.
  • Fig. 5 is a schematic diagram of a collimating hole in an optical collimator according to an embodiment of the present application.
  • Fig. 6 is a cross-sectional view of an optical collimator with a square annular collimating hole according to an embodiment of the present application.
  • Fig. 7 is a top view of an optical collimator with a square annular collimating hole according to an embodiment of the present application.
  • Fig. 8 is a cross-sectional view of a composite optical collimator according to an embodiment of the present application.
  • Fig. 9 is a top view of a composite optical collimator according to an embodiment of the present application.
  • Fig. 10 is a top view of an optical collimator with a square through hole layer according to an embodiment of the present application.
  • FIG. 11 is a top view of an optical collimator having a through hole layer composed of a plurality of circular through holes according to an embodiment of the present application.
  • Fig. 12 is a cross-sectional view of another optical collimator according to an embodiment of the present application.
  • Fig. 13 is a cross-sectional view of an optical collimator for quasi-oblique holes according to an embodiment of the present application.
  • Fig. 14 is a schematic diagram of an optical collimator integrated on an image sensor according to an embodiment of the present application.
  • FIG. 15 is a schematic flowchart of a method for manufacturing an optical collimator according to an embodiment of the present application.
  • Figure 1 shows the principle of an optical under-screen fingerprint recognition technology based on a collimator.
  • a light source such as a screen or a light emitting diode (LED)
  • the reflected light 15 enters the screen 11 again, passes through the collimator 14 below the screen 11, and finally reaches the image sensor 13.
  • the image sensor 13 may include one or more photosensitive units 131, and the reflected light 15 passes through the screen 11 And the collimator 14 below can finally reach the photosensitive unit 131.
  • the reflected light 15 may include light reflected on the surface of the finger 12 to form reflected light, and scattered light inside the finger 12 to form scattered light.
  • reflected light 15 the above-mentioned reflected light and scattered light are collectively referred to as reflected light 15.
  • the image sensor 13 can obtain a fingerprint image with a certain contrast between light and dark, and combine the collected fingerprint image with the storage device.
  • the fingerprint information entered is compared to achieve the effect of identity authentication.
  • the main function of the collimator 14 shown in FIG. 1 is to allow collimated or nearly collimated light to pass through the area, while the oblique light is blocked by the collimator 14.
  • FIG. 2 is a schematic diagram of the angle of light in the collimating hole of the collimator.
  • the aperture of the collimating hole of the collimator 21 is s, and the depth of the collimator 21 is t; in addition, taking any point O as the incident point as an example, the light 201 in Fig. 2 is The included angle of the main optical axis 221 of the sensor is ⁇ , and the included angle ⁇ is the critical value of the angle at which the incident light passing through the point O can reach the photosensitive unit 22.
  • the collimator 21 is blocked and cannot be received by the photosensitive unit 22 below (in the case where the reflection of the light 202 is not considered).
  • An important factor that affects the angle ⁇ is the aspect ratio (AR) of the collimator hole (also called the light-transmitting hole) in the collimator, that is, the ratio of the depth t of the hole to the aperture s in FIG. 2. Obviously, the larger the aspect ratio, the smaller the ⁇ , so the aspect ratio becomes an important indicator to measure the characteristics of the collimator.
  • the collimator can be a separate optical component (discrete), it can also be integrated in the image sensor (integrated).
  • the advantage of the discrete collimator is that it can obtain a high aspect ratio, such as through silicon vias made by the TSV process; its disadvantage is that the cost is relatively high.
  • the integrated collimator is implemented based on the metal layer in the CMOS back-end process. The advantage is that there is no additional process cost. However, since the thickness and opening size of the metal layer are limited by the process, it is difficult to further increase the aspect ratio.
  • this application provides a new optical collimator structure and manufacturing method, which can effectively increase the aspect ratio, thereby improving Its spatial filtering capacity.
  • the optical collimator in the embodiment of the present application can be regarded as a combination of multiple sub-collimators, for example, it can include 2N-1 sub-collimators from bottom to top, where N ⁇ 2, for ease of description, The description will be given below by taking FIGS. 3 to 14 as examples.
  • FIG. 3 shows a cross-sectional view of the optical collimator 30 according to an embodiment of the present application
  • FIG. 4 shows a top view of the optical collimator 30 according to an embodiment of the present application, wherein FIG. 3 is the dashed line AA′ in FIG. 4 Indicated profile view.
  • a collimating hole is provided on the first metal layer 301, thereby forming a first sub-collimator 31; similarly, in the first metal layer 301, A second metal layer 303 is also provided above a metal layer 301, and a collimating hole is provided on the second metal layer 303, thereby forming a third sub-collimator 33; in addition, the first metal layer 301 and the The dielectric layer between the second metal layers 303 is called the first through hole layer 302.
  • the first through hole layer 302 is provided with a first through hole, and the first through hole is filled with metal so that the metal is filled
  • the first through hole of may connect the first metal layer 301 and the second metal layer 303, and the first through hole layer 302 is the second sub-collimator 32.
  • the i-1th through hole layer is provided with the i-1th through hole
  • Metal is filled in the via to connect the i-1th metal layer and the i-th metal layer
  • the i-1th through-hole layer is the 2i-2th sub-collimator, and i takes 2, 3,...N in turn
  • a collimating hole is arranged on the i-th metal layer to form a 2i-1th sub-collimator, and the i-th metal layer is located above the i-1th metal layer.
  • the 2N-1 sub-collimators included in the optical collimator of the embodiment of the present application are alternately formed by metal layers and through-hole layers. Among them, there are N sub-collimators formed by the metal layer. There are N-1 sub-collimators formed by layers.
  • a collimating hole is provided on the metal layer to form a sub-collimator, wherein the thickness of the metal layer can be set according to actual applications, and the thickness of the different metal layers It can be set to be the same or different; the shape of the collimating hole can be set arbitrarily according to the actual application; and the number of collimating holes included in each metal layer can also be set according to the actual application; in addition, the shape of the collimating holes on different metal layers The number and shape of the collimating holes may be the same or different. When there are multiple collimating holes on the same metal layer, the shapes of different collimating holes may also be the same or different. That is, the sub-collimator formed by any metal layer may include one or more collimating holes, and the shape of each collimating hole may be set according to actual applications, and the embodiment of the present application is not limited thereto.
  • FIG. 5 is a schematic diagram of a collimating hole on any metal layer of the optical collimator according to an embodiment of the application.
  • the metal layer may include one or more collimating holes.
  • the metal layer includes only one collimating hole, it can be single-hole type or ring-shaped, if it is single-hole type, the collimating hole can be any regular or irregular shape, as shown in Figure 5 5 kinds of shapes; if the collimating hole is a ring shape, the ring shape can also be any regular or irregular shape, and the inner and outer shapes of the ring shape can also be the same or different, as shown in Figure 5 There are five ring types, but the embodiments of the present application are not limited thereto.
  • the metal layer may also include a plurality of collimating holes, and the shape of each collimating hole may be the same or different, and the arrangement of the plurality of collimating holes may also be set arbitrarily according to actual applications. For example, assuming that the metal layer includes a plurality of identical circular collimating holes, the arrangement of the plurality of collimating holes can be arranged as shown in FIG. 5, but the embodiment of the present application is not limited to this.
  • the aperture of the corresponding collimating hole and the determination method of the central axis may also be different.
  • the collimating hole is circular
  • the diameter of the collimating hole is the diameter of the circle
  • the central axis of the collimating hole is the through circle
  • the aperture of the collimating hole can be the height of the regular triangle
  • the central axis of the collimating hole can be set as a vertical axis passing through the intersection of the three heights of the regular triangle
  • the aperture of the collimating hole can be the length of a side of the rectangle or polygon, or it can be the diagonal length of the rectangle or polygon
  • the central axis of the rectangle or polygon can be It is the vertical axis passing through the intersection of the diagonals, and the embodiment of the present application is not
  • the collimating holes of each metal layer are set to be circular, and the aperture of the collimating hole of the sub-collimator corresponding to each metal layer is as follows
  • the central axis of the collimating hole is the axis 300 passing through the center of the circle.
  • the aperture of the collimating hole may refer to the width of the ring-shaped ring, and the collimating hole
  • the central axis of can refer to the central line of the ring-shaped ring, or it can also refer to the central axis of the ring-shaped internal figure.
  • the aperture of the collimating hole is the width of the circular ring, that is, the difference between the radii of the inner and outer circles;
  • the central axis of the circular ring can refer to the circle passing through the inner
  • the axis of the center of the circle can also refer to the midline between the inner and outer circles of the ring.
  • the aperture of the collimating hole is the width of the square ring, that is, half of the difference between the side lengths of the inner and outer squares;
  • the central axis of the square ring can refer to the square passing through the inner
  • the axis of the center may also refer to the midline between the inner and outer squares of the square ring.
  • FIG. 6 shows a cross-sectional view of the optical collimator 40 according to an embodiment of the present application
  • FIG. 7 shows a top view of the optical collimator 40 according to an embodiment of the present application, where FIG. 6 is the dashed line in FIG. 7 Section view indicated by BB'.
  • the collimating holes of the sub-collimators corresponding to each metal layer of the optical collimator 40 are all square rings, and the collimating holes of the sub-collimator corresponding to each metal layer are square rings.
  • the aperture is the width s of the square ring as shown in Figs. 6 and 7, and s is also equal to half of the difference between the side lengths of the inner and outer squares.
  • the central axis of the square annular collimating hole may refer to the inner square center line 400, or may also refer to the center line 420 between the inner and outer squares, and the embodiment of the present application is not limited thereto.
  • the aperture of each collimation hole and the determination method of the central axis can be determined according to the determination method of the single collimation hole described above; For the determination of the central axis, other methods can also be used.
  • the collimating hole of the metal layer is composed of two parallel circles as shown in the porous type in the middle of FIG. 5, the metal layer
  • the central axis of the collimating hole can also be an axis passing through the midpoint of the two circular circular lines, but the embodiment of the present application is not limited to this.
  • the optical collimator in the embodiment of the present application may include multiple metal layers. If different metal layers include collimating holes of different shapes, the apertures of the collimating holes of different metal layers may also be different. It may also be different, wherein the aperture and the central axis of the collimating hole of each metal layer can be determined separately according to its shape. Wherein, if the collimating holes of the multiple metal layers have the same shape, the same method is adopted to determine the diameter and central axis of the collimating holes of each layer.
  • FIG. 8 shows a cross-sectional view of an optical collimator 50 according to an embodiment of the present application
  • FIG. 9 shows a top view of an optical collimator 50 according to an embodiment of the present application
  • FIG. 8 is the dashed line in FIG. 9 CC' indicates the sectional view.
  • the collimating hole of the sub-collimator 51 of the first metal layer 501 and the collimating hole of the sub-collimator 53 of the second metal layer 503 have the same shape, and both are circular rings, but The collimating hole of the sub-collimator 55 of the third metal layer 505 is circular.
  • the method for determining the central axis of the collimating hole of the sub-collimator 51 of the first metal layer 501 and the collimating hole of the sub-collimator 53 of the second metal layer 503 is the same, for example, both can be set to 520, or both It is set to 500; and the central axis of the collimating hole of the sub-collimator 55 of the third metal layer 505 can be set to 500.
  • the diameters of the collimating hole of the sub-collimator 51 of the first metal layer 501 and the collimating hole of the sub-collimator 53 of the second metal layer 503 are both s; while the diameter of the sub-collimator 55 of the third metal layer 505
  • the diameter of the collimating hole is a circular diameter of 2s+d.
  • each metal layer in the optical collimator of the embodiment of the present application is provided with a collimating hole
  • each metal layer can be divided into a collimating hole area and a metal area except the collimating hole.
  • the material of the metal region of each metal layer in the embodiments of the present application may be any metal, and the materials of different metal layers may be the same or different.
  • the materials of the collimating hole region of the metal layer and other dielectric filling regions 310 in the embodiments of the present application can be set according to actual applications.
  • the dielectric 310 can be silicon dioxide (SiO 2 ) and/or silicon nitride (Si 3 N 4 ), but the embodiment of the application is not limited to this.
  • the through hole between the two metal layers in the embodiments of the present application is provided with metal, which can be used to connect the upper and lower metal layers, which can specifically refer to the metal region where the through hole connects the upper and lower metal layers.
  • the first via layer 302 between the first metal layer 301 and the second metal layer 303 in the optical collimator 30 shown in FIGS. 3 and 4 is taken as an example for description.
  • the first metal layer 301 and the second metal layer 303 are both provided with collimating holes, the area outside the collimating holes is referred to as a metal area, and the first through hole provided on the first through hole layer 302 is connected to the The first metal layer 301 and the second metal layer 303 may refer to: the first through hole connects the metal area of the first metal layer 301 and the metal area of the second metal layer 303, that is, the top and bottom of the through hole are only Contact with metal areas, but not non-metal areas.
  • any through hole layer of the N-1 through hole layers in the optical collimator of the embodiment of the present application may include at least one through hole, and the thickness of different through hole layers can be set according to actual applications.
  • the thickness of different via layers can be set to be the same or different; and different via layers can have the same or different number of vias, and the shape of each via can be set arbitrarily according to actual applications.
  • any via layer is taken as an example for description.
  • the shape of the through hole of the through hole layer can be set with reference to the shape of the collimating hole of the metal layer.
  • the collimating hole of each metal layer in the optical collimator 30 is circular, and the through holes in each through hole layer can be set to be larger than the diameter of the collimating hole of the metal layer.
  • Ring that is, the ring area of the ring is set as a through hole, and metal is filled in the ring area to connect the upper and lower metal layers.
  • the diameter of the collimating hole of the through hole layer is equal to the diameter s of the collimating hole of the metal layer.
  • the collimation hole of each metal layer in the optical collimator 40 is a square ring, and the through hole in the through hole layer can be set to correspond to two squares inside and outside the metal layer collimation hole. Two square rings to facilitate the connection of the upper and lower metal layers respectively.
  • the through holes of the through hole layer are set as shown in FIG. 6 and FIG. 7, the diameter of the collimating hole of the through hole layer is equal to the diameter of the collimating hole s of the metal layer.
  • the through hole of the through hole layer may also be set to any shape that does not correspond to the shape of the collimating hole of the metal layer.
  • the collimating holes of each metal layer are of the same circle, and the through holes of the through hole layer can be circular as shown in FIG.
  • the through hole of the through hole layer can also be a ring structure with an inner circle and an outer square as shown in FIG. 10, that is, the part of the ring structure with an inner circle and an outer square is the through hole of the through hole layer; or,
  • the via layer can also be provided as a plurality of via holes as shown in FIG. 11.
  • the plurality of via holes can be of any shape and number, and are arranged in the metal regions of the upper and lower metal layers.
  • the hole layer 302 or 304 may include four through holes of the same shape, which are evenly arranged in the area around the collimating hole of the metal layer, but the embodiment of the present application is not limited thereto.
  • the collimation holes of the sub-collimator formed by the through hole layer refer to the sub-collimation holes in the through hole layer other than the through holes and are aligned with the sub-collimators formed in the metal layer.
  • Corresponding part of the collimator hole corresponds to a part other than the through hole and that is consistent with the position of the collimation hole of the upper and lower metal layers.
  • the method for calculating the aperture of the collimator hole of the sub-collimator formed in the through hole layer can refer to the calculation method for the aperture of the collimator hole of the sub-collimator of the metal layer described above. For brevity, it will not be repeated here.
  • the through holes of the through hole layer in the embodiments of the present application are filled with metal, and the material of the metal can be set according to actual applications.
  • the material can be set to tungsten and/or copper.
  • the apertures of the collimating holes of the 2N-1 sub-collimators included in the optical collimator may be the same or different.
  • the light flux of the optical collimator is related to the sub-collimator with the smallest aperture.
  • the diameters of the collimating holes of the 2N-1 collimators are all set to the same value s.
  • the optical collimator 60 is similar to the optical collimator 30 in FIG. 3, and also includes five sub-collimators, but the collimating holes of the five sub-collimators are not completely the same.
  • the amount of light passing through the optical collimator 60 is related to the smallest collimating hole. For example, as shown in FIG. 12, assuming that the apertures of the collimating holes of the first sub-collimator and the fifth sub-collimator are the smallest and equal, and both are equal to s, then the light flux of the optical collimator 60 is the same as that of FIG. The amount of light transmitted is equal to that of the optical collimator 30 in FIG. 4.
  • the 2N-1 sub-collimators included in the optical collimator in this embodiment of the application can be set to meet the following conditions: the collimation of the first sub-collimator
  • the hole diameter is the minimum of the collimating hole diameter of the 2N-1 sub-collimators, from the first sub-collimator to the sub-collimator formed on the metal layer in the 2n-1 sub-collimator
  • the collimating holes have the same shape and the same aperture, n is a positive integer, 2 ⁇ n ⁇ N, the center axis of the collimating hole of the 2j-3th sub-collimator and the collimation of the 2j-1th sub-collimator
  • the offset direction between the central axes of the holes is the preset direction and the offset distance is the preset value, j is a positive integer, and j is 2, 3,...n in turn.
  • the optical collimator includes 2N-1 sub-collimators, the shape and size of the collimating holes of the sub-collimators corresponding to the metal layer in the 2N-1 sub-collimators are the same, and the collimating holes The central axis coincides.
  • the shape and size of the collimating holes of the sub-collimators of the corresponding through-hole layer in the 2N-1 sub-collimators may also be set to be the same, and the central axis of these collimating holes may also be set to coincide.
  • the shape of the collimating hole of the sub-collimator corresponding to the through-hole layer of the 2N-1 sub-collimators may be the same as or different from the shape of the collimating hole of the sub-collimator corresponding to the metal layer;
  • the apertures of the collimating holes can also be the same or different.
  • the aperture of the collimating hole of the sub-collimator corresponding to the through-hole layer can be set to be larger than the aperture of the collimating hole of the sub-collimator corresponding to the metal layer;
  • the central axis of the collimating hole of the sub-collimator may be set to be the same as the central axis of the collimating hole of the sub-collimator corresponding to the metal layer, or there may be an offset distance, and the embodiment of the present application is not limited thereto.
  • the optical collimator in this first embodiment may be set as the optical collimator 30 as shown in FIGS. 3 and 4.
  • the optical collimator 30 is composed of five sub-collimators formed by three metal layers and two through-hole layers. As shown in FIGS.
  • the optical collimator 30 includes: The sub-collimator 31 of the round hole-shaped collimating hole formed by the first metal layer 301 has an aperture of s and a depth of t; the sub-collimator 32 of the round hole-shaped collimating hole formed by the first through-hole layer 302 , The aperture is s and the depth is h; the sub-collimator 33 of the round hole-shaped collimating hole formed by the second metal layer 303 has the aperture s and the depth is t; the circle formed by the second through-hole layer 304 The sub-collimator 34 of the hole-shaped collimating hole has an aperture of s and the depth is h; the sub-collimator 35 of the round hole-shaped collimating hole formed by the third metal layer 305 has an aperture of s and a depth of t .
  • the five sub-collimators 31 to 35 are stacked in such a way that the central symmetry axis 300 overlaps, that is, the main optical axis of the optical collimator 30 is 300. Therefore, the aspect ratio AR of the optical collimator 30 can be described by the following formula (1):
  • the aspect ratio of the optical collimator 30 is significantly improved.
  • the material of the metal layers 301, 303, and 305 can be aluminum (Al), copper (Cu) or titanium nitride (TiN), etc.; in the via layers 302 and 303, the filling metal in the via can be It is tungsten (W) or copper (Cu), etc., and the area other than metal is filled with an intermetallic dielectric 310.
  • the material of the dielectric 310 can be silicon dioxide (SiO 2 ) or silicon nitride (Si 3 N 3 ) Wait.
  • the specific manufacturing method of each layer of the optical collimator 30 can refer to the standard CMOS process, which will not be repeated here.
  • the optical collimator in the first embodiment can also be configured as the optical collimator 40 shown in FIGS. 6 and 7.
  • the light transmission channel is a circular hole
  • the light transmission channel of the collimator 40 is a square ring, which has the advantage of ensuring a certain filtering effect.
  • This ring-shaped collimator 40 is also composed of five ring-shaped sub-collimators 61-65 with the same size formed by three metal layers and two through-hole layers.
  • each layer is sequentially stacked in a manner in which the central symmetry axis 400 overlaps, so the aspect ratio is also shown in the above formula (1). Since its structure is basically similar to the collimator 30, it will not be repeated here.
  • the optical collimator satisfies: the offset distance of the central axis is zero, that is, the preset value is equal to 0, and n is less than N.
  • the first sub-collimator to the 2n-1th sub-collimator in the optical collimator satisfy: the shape of the collimating hole of the sub-collimator corresponding to the metal layer in the 2n-1 sub-collimator And the dimensions are the same, and the central axes of these collimating holes coincide.
  • the shape and size of the collimating holes of the sub-collimators of the corresponding through-hole layer in the 2n-1 sub-collimators may also be set to be the same, and the central axis of these collimating holes may also be set to coincide.
  • the shape of the collimating hole of the sub-collimator corresponding to the through-hole layer in the 2n-1 sub-collimators may be the same as or different from the shape of the collimating hole of the sub-collimator corresponding to the metal layer;
  • the apertures of the collimating holes can also be the same or different.
  • the aperture of the collimating hole of the sub-collimator corresponding to the through-hole layer can be set to be larger than the aperture of the collimating hole of the sub-collimator corresponding to the metal layer;
  • the central axis of the collimating hole of the sub-collimator may be set to be the same as the central axis of the collimating hole of the sub-collimator corresponding to the metal layer, or there may be an offset distance, and the embodiment of the present application is not limited thereto.
  • the 2nth sub-collimator to the 2N-1th sub-collimator, you can refer to the 2n-1 sub-collimators for setting.
  • it can also be set so that the collimating holes have the same shape and size. And the central axis of these collimating holes coincide.
  • FIGS. 8 and 9 show the structure of a composite collimator 50 with a high aspect ratio.
  • the upper part of the light-transmitting passage of the composite collimator 50 is a hole, and the lower part is a ring.
  • the use of this composite structure can further increase the aspect ratio.
  • the composite collimator 50 includes: a sub-collimator 51 with a circular collimating hole formed by the first metal layer 501, the main optical axis of which is 520, the size of the circular light transmission channel is s, and the depth is t
  • the sub-collimator 53 of the circular collimating hole has a main optical axis of 520, the size of the circular light transmission channel is s, and the depth is t; the sub-collimator of the circular hole-shaped collimating hole formed by the second through hole layer 504
  • the main optical axis of the collimator 54 is 500, the aperture is 2s+d, and the depth is h; the sub-collimator 55 of the round hole-shaped collimating hole formed by the third metal layer 505 has
  • the depth of the sub-collimator 55 is 4t.
  • the sub-collimators 51 to 55 are sequentially stacked in such a way that the central symmetry axis 500 overlaps.
  • the calculation shows that the aspect ratio of the collimator 50 is:
  • the light-transmitting channel structure of the composite collimator 50 can also have other combinations.
  • the composite collimator can be a combination of a large hole in the upper part and several small holes in the lower part, or it can also be a generous upper part.
  • the lower part of the hole is a small round hole or a ring-shaped hole, and the embodiment of the present application is not limited thereto.
  • the optical collimator in the embodiment of the present application may also be an oblique hole collimator, that is, the sub-collimators included in the collimator may have a certain offset distance in a predetermined direction.
  • the collimating holes of the sub-collimators corresponding to any two adjacent metal layers in the 2N-1 sub-collimators may satisfy: The central axis of the two collimating holes is offset along the preset direction by a preset distance.
  • the offset distance setting can also be satisfied, that is, the collimation of the 2j-3th sub-collimator in the 2N-1 sub-collimators
  • the offset direction between the center axis of the hole and the center axis of the collimating hole of the 2j-2th sub-collimator is the preset direction, and the offset distance is half of the preset value.
  • FIG. 13 shows the structure of an oblique hole collimator 70, and its cross-sectional view is shown in FIG.
  • the collimator 70 includes: a sub-collimator 71 with a circular hole-shaped collimating hole formed by the first metal layer 701, the aperture of which is s and the depth is t; the circle formed by the first through hole layer 702
  • the sub-collimator 72 of the hole-shaped collimating hole has an aperture of w and a depth of h.
  • the offset distance 721 of the central axis of the sub-collimator 72 to the right relative to the central axis of the sub-collimator 71 is 0.5* (h+t)tan ⁇ ;
  • the offset distance 732 of the central axis 72 to the right is also 0.5*(h+t)tan ⁇ ;
  • the sub-collimator 74 of the round hole-shaped collimating hole formed by the second through-hole layer 704 has a hole diameter of w and a depth Is h, the offset distance 743 of the central axis of the sub-collimator 74 relative to the central axis of the sub-collimator 73 to the right is 0.5*(h+t)tan ⁇ ;
  • a quasi-oblique hole collimator 70 whose main optical axis is at an angle of ⁇ relative to the normal line of the incident surface can be obtained.
  • the quasi-oblique hole collimator 70 can have an incident angle of ⁇
  • the oblique incident light has a certain spatial filtering effect.
  • the offset distance of the central axis is not zero, that is, when the preset value is not equal to 0, n can also be set to be less than N, that is, the optical collimator 50 and the optical collimator For the sake of brevity, it will not be repeated here.
  • the optical collimator may be a separate optical component (discrete type) or integrated in the image sensor (integrated type).
  • the optical collimator in the embodiment of the present application may be applied to the fingerprint indicator module as shown in FIG. 1.
  • the optical collimator may be provided separately, or may be integrated into the CMOS image sensor.
  • FIG. 14 shows a case where the collimator 80 is integrated on the CMOS image sensor.
  • the collimator 80 is composed of three round hole-shaped collimating hole collimators formed by two metal layers and a through-hole layer.
  • the collimator 80 includes: a first metal
  • the sub-collimator 81 formed by the layer 801 has an aperture of s and a depth of t; the sub-collimator 82 formed by the first through-hole layer 802 has an aperture of s and a depth of h; and the sub-collimator formed by the second metal layer 803
  • the collimator 83 has an aperture of s.
  • the second metal layer is the top metal, its thickness can be 4t, so the collimating hole depth of the sub-collimator 83 is 4t.
  • the apertures of the sub-collimators 81, 82, and 83 are all s, and the main optical axes are all the same optical axis 800. Therefore, the aspect ratio of the collimator 80 is:
  • the high-aspect-ratio collimator can filter out stray light from the non-fingerprint reflection screen, while the reflected light carrying fingerprint information can be The collimator is then absorbed by the photosensitive unit 820 on the image sensor, and finally an image with a high signal-to-noise ratio is obtained.
  • the optical collimator according to the embodiment of the present application is provided with multiple metal layers to form an optical collimator composed of multiple sub-collimators, which can solve the problem that the aspect ratio of the existing integrated collimator is difficult to improve , Which effectively increases the aspect ratio, thereby improving its spatial filtering capacity.
  • FIG. 15 shows a schematic flow chart of a method 900 for manufacturing an optical collimator according to an embodiment of the present application.
  • the method 900 includes: S910, arranging a collimator on the first metal layer.
  • a collimating hole is provided on the second metal layer to form a third sub-collimator, the second metal layer is located above the first metal layer;
  • S930 in An i-1 th through hole is provided in the i-1 th through hole layer between the i-1 th metal layer and the i th metal layer, and the i-1 th through hole is filled with metal to connect the i-1 th through hole
  • the metal layer and the i-th metal layer, the i-1th through-hole layer is the 2i-2th sub-collimator, i takes 2, 3,...N in turn, and N is a positive integer greater than 1;
  • S940 A collimating hole is provided on the i-th metal layer to form a 2i-1th sub-collimator, and the i-th metal layer is located above the i-1th metal layer.
  • the method 900 may be used to manufacture the optical collimator in the embodiment of the present application, for example, may be used to manufacture any one of the optical collimators 30-80 in the embodiment of the present application.
  • the first sub-collimator to the 2n-1th sub-collimator satisfy: the first sub-collimator
  • the collimating hole diameter of the 2N-1 sub-collimator is the minimum value of the collimating hole diameter of the 2N-1 sub-collimator, and the sub-collimator formed on the metal layer from the first sub-collimator to the 2n-1 sub-collimator
  • the collimating holes of the collimator have the same shape and the same diameter, n is a positive integer, 2 ⁇ n ⁇ N, the central axis of the collimating hole of the 2j-3th sub-collimator and the 2j-1th sub-collimator
  • the offset direction between the central axes of the collimating holes is a preset direction and the offset distance is a preset value, j is a positive integer, and j is 2, 3, ... n in turn.
  • the shapes of the collimating holes from the first sub-collimator to the 2n-1th sub-collimator are the same.
  • the preset value is zero.
  • n N.
  • the collimating holes of the 2N-1 sub-collimators have the same diameter.
  • the preset value is greater than zero.
  • the offset direction between the central axis of the collimating hole of the 2j-3th sub-collimator and the central axis of the collimating hole of the 2j-2th sub-collimator is the preset Set the direction and the offset distance is half of the preset value.
  • the manufacturing method of the optical collimator according to the embodiment of the present application forms an optical collimator composed of a multi-layer sub-collimator by providing multiple metal layers, which can solve the problem of the existing integrated collimator aspect ratio.
  • the problem of improvement effectively increases the aspect ratio, thereby improving its spatial filtering capability.
  • the optical collimator of the embodiment of the present application may be applied to an optical fingerprint recognition module.
  • the optical fingerprint recognition module may include the optical collimator and the image sensor of the embodiment of the present application, wherein the image The sensor is arranged below the optical collimator, and the optical collimator is used to filter the returning light reflected by the finger and converge to the image sensor; the image sensor is used to receive the returning light passing through the optical collimator and The fingerprint data is generated according to the received return light, and the fingerprint data is used for fingerprint identification of the finger.
  • the optical fingerprint recognition module may be as shown in FIG. 1, where the optical collimator 14 is the optical collimator in the embodiment of the application, for example, it may be any one of the optical collimators 30-80. Straightener.
  • the optical collimator 14 may be a separate optical component (discrete), or integrated in the image sensor (integrated).
  • the optical collimator 80 is integrated on the image sensor 820.
  • the optical fingerprint recognition module may further include: a light source for generating light, and the light is used for illuminating the finger and reflecting to generate the return light.
  • the above-mentioned optical fingerprint recognition module may be applied to a terminal device.
  • the terminal device may include: a display screen for providing a touch interface for a finger; an optical fingerprint recognition module located below the display screen for Perform fingerprint recognition on the finger.
  • the display screen may also be used as a light source.
  • the display screen may further include: light-emitting display pixels for displaying images and emitting light, and the light is used to illuminate the finger and reflect the returning light.
  • Figure 1 shows a part of the terminal device, that is, the part of the terminal device corresponding to the optical collimator 14 and the image sensor 13.
  • the terminal device also includes a display screen 11, but The embodiments of the present application are not limited to this.
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or It can be integrated into another system, or some features can be ignored or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • each unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of this application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other media that can store program code .

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Abstract

一种光学准直器（30），包括2N-1个子准直器（31,32,33,34,35,），N>1的正整数，其中第一金属层（301）上设置有准直孔，形成第一个子准直器（31）；位于该第一金属层（301）上方的第二金属层（303）上设置有准直孔，形成第三个子准直器（33）；第i-1金属层与第i金属层之间为第i-1通孔层，该第i-1通孔层中设置有第i-1通孔，填充金属的该第i-1通孔用于连接该第i-1金属层与该第i金属层，该第i-1通孔层为第2i-2个子准直器，i依次取2,3,……N；位于第i-1金属层上方的该第i金属层上设置有准直孔，形成该2N-1个子准直器中的第2i-1个子准直器。还涉及一种光学准直器的制作方法。该光学准直器能够提高其对光的空间过滤能力。

Description

光学准直器及其制作方法 技术领域
本申请涉及光学器件领域，尤其涉及光学准直器及其制作方法。
背景技术
随着手机全面屏时代的来临，屏下指纹识别逐渐成为技术热点。按照实现原理的差异，屏下指纹识别通常可分为光学式、超声波式以及电容式三种。其中，对于光学式指纹识别模组，通常设置有准直器，用于将从手指表面反射回来的反射光导引至下方的图像传感器进行光学检测。
准直器可以是一个单独的光学组件(分立式)，也可以是集成在图像传感器之中(集成式)。分立式准直器的优点是可获得高深宽比，例如通过硅通孔(Through Silicon Via，TSV)工艺制作的硅通孔，但是其缺点是成本较高。而集成式准直器则是基于互补金属氧化物半导体(Complementary Metal Oxide Semiconductor，CMOS)后道工艺中的金属层实现，优点是没有额外的工艺成本，但由于金属层的厚度和开口尺寸均受工艺所限制，因而深宽比难以进一步提高。
发明内容
本申请提供了一种光学准直器及其制作方法，能够提高光学准直器的深宽比，进而提高其对光的空间过滤能力。
第一方面，提供了一种光学准直器，该光学准直器包括：2N-1个子准直器，N为大于1的正整数，其中，第一金属层上设置有准直孔，形成该2N-1个子准直器中的第一个子准直器；第二金属层上设置有准直孔，形成该2N-1个子准直器中的第三个子准直器，该第二金属层位于该第一金属层上方；第i-1金属层与第i金属层之间为第i-1通孔层，该第i-1通孔层中设置有第i-1通孔，填充金属的该第i-1通孔用于连接该第i-1金属层与该第i金属层，该第i-1通孔层为该2N-1个子准直器中的第2i-2个子准直器，i依次取2,3,……N；该第i金属层上设置有准直孔，形成该2N-1个子准直器中的第2i-1个子准直器，该第i金属层位于该第i-1金属层上方。
结合第一方面，在第一方面的一种实现方式中，该2N-1个子准直器中 该第一个子准直器至第2n-1个子准直器满足：该第一个子准直器的准直孔孔径为该2N-1个子准直器的准直孔孔径的最小值，该第一个子准直器至该第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相等，n为正整数，2≤n≤N，第2j-3个子准直器的准直孔的中轴线与该第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该第一个子准直器至该第2n-1个子准直器的准直孔的形状相同。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该预设值为零。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，n＝N。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该2N-1个子准直器的准直孔孔径相等。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该预设值大于零。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该第2j-3个子准直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为该预设方向，且偏移距离为该预设值的一半。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该第一金属层以及该第i金属层的材料为以下材料中的至少一种：铝、铜和氮化钛。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该第i-1通孔层中通孔内填充的金属的材料为钨和/或铜。
结合第一方面及其上述实现方式，在第一方面的另一种实现方式中，该光学准直器的准直孔内的填充材料为二氧化硅和/或氮化硅。
因此，本申请实施例的光学准直器，通过设置多层金属层，从而形成多层子准直器构成的光学准直器，能够解决现有集成式准直器深宽比难以提升的问题，有效增加了深宽比，从而提高其空间过滤能力。
第二方面，提供了一种光学准直器的制作方法，该方法包括：在第一金属层上设置准直孔，以形成第一个子准直器；在第二金属层上设置准直孔， 以形成第三个子准直器，该第二金属层位于该第一金属层上方；在第i-1金属层与第i金属层之间的第i-1通孔层中设置第i-1通孔，并在该第i-1通孔内填充金属，以连接该第i-1金属层与该第i金属层，该第i-1通孔层为第2i-2个子准直器，i依次取2,3,……N，N为大于1的正整数；在该第i金属层上设置准直孔，以形成第2i-1个子准直器，该第i金属层位于该第i-1金属层上方。
结合第二方面，在第二方面的一种实现方式中，该光学准直器的2N-1个子准直器中该第一个子准直器至第2n-1个子准直器满足：该第一个子准直器的准直孔孔径为该2N-1个子准直器的准直孔孔径的最小值，该第一个子准直器至该第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相等，n为正整数，2≤n≤N，第2j-3个子准直器的准直孔的中轴线与该第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，该第一个子准直器至该第2n-1个子准直器的准直孔的形状相同。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，该预设值为零。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，n＝N。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，该2N-1个子准直器的准直孔孔径相等。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，该预设值大于零。
结合第二方面及其上述实现方式，在第二方面的另一种实现方式中，该第2j-3个子准直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为该预设方向，且偏移距离为该预设值的一半。
第三方面，提供了一种光学指纹识别模组，包括：上述第一方面或第一方面的任意可能的实现方式中的光学准直器以及图像传感器，该图像传感器设置在该光学准直器的下方，该光学准直器用于：过滤经过手指反射的返回光并汇聚至该图像传感器；该图像传感器用于：接收经过该光学准直器的该返回光并根据接收到的该返回光生成指纹数据，该指纹数据用于对该手指进 行指纹识别。
结合第三方面，在第三方面的一种实现方式中，该光学指纹识别模组还包括：光源，用于产生光，该光用于照亮该手指并反射产生该返回光。
第四方面，提供了一种终端设备，包括：显示屏，用于为手指提供触摸界面；上述第三方面或第三方面的任意可能的实现方式中的光学指纹识别模组，位于该显示屏下方，用于对该手指进行指纹识别。
结合第四方面，在第四方面的一种实现方式中，该显示屏包括：发光显示像素，用于显示图像以及发光，该光用于照亮该手指并反射产生该返回光。
附图说明
图1是根据本申请实施例的基于准直器的一种光学式屏下指纹识别技术的原理的示意图。
图2是根据本申请实施例的准直器的准直孔内光线的角度的示意图。
图3是根据本申请实施例的一种光学准直器的剖面图。
图4是根据本申请实施例的一种光学准直器的俯视图。
图5是根据本申请实施例的光学准直器中准直孔的示意图。
图6是根据本申请实施例的方环形准直孔的光学准直器的剖面图。
图7是根据本申请实施例的方环形准直孔的光学准直器的俯视图。
图8是根据本申请实施例的复合型光学准直器的剖面图。
图9是根据本申请实施例的复合型光学准直器的俯视图。
图10是根据本申请实施例的具有方形通孔层的光学准直器的俯视图。
图11是根据本申请实施例的具有多个圆形通孔构成的通孔层的光学准直器的俯视图。
图12是根据本申请实施例的另一种光学准直器的剖面图。
图13是根据本申请实施例的准斜孔的光学准直器的剖面图。
图14是根据本申请实施例的集成在图像传感器上的光学准直器的示意图。
图15是根据本申请实施例的光学准直器的制作方法的示意性流程图。
具体实施方式
下面将结合附图，对本申请实施例中的技术方案进行描述。
图1示出了基于准直器(collimator)的一种光学式屏下指纹识别技术的原理。具体地，如图1所示，当手指12按在手机屏幕11上的特定区域时，由光源(例如屏幕或发光二极管(Light Emitting Diode，LED))发出的光照到手指12的表面产生反射光15，反射光15再次进入屏幕11，并经过屏幕11下方的准直器14，最终抵达图像传感器13，具体地，该图像传感器13可以包括一个或者多个感光单元131，反射光15经过屏幕11以及下方的准直器14，最终可以抵达感光单元131。其中，该反射光15可以包括光在手指12的表面发生反射形成反射光以及经过所述手指12内部散射而形成散射光，为便于描述，上述反射光和散射光统称为反射光15。
由于手指12上指纹的嵴121(ridge)和峪122(valley)对于光的反射能力不同，因而图像传感器13可以获得具有一定明暗对比度的指纹图像，并将采集到的指纹图像与储存器中已录入的指纹信息进行比对来达到身份认证的效果。在上述过程中，图1所示的准直器14的主要作用是允许准直或近似准直的光通过该区域，而倾斜的光则被准直器14所阻挡。
准直器对于光的空间过滤能力可以用角度θ来描述，即将θ定义为可以通过准直器的入射光的最大倾斜角度。具体地，图2为准直器的准直孔内光线的角度的示意图。如图2所示，准直器21的准直孔的孔径为s，准直器21的深度为t；另外，这里以任意一点O为入射点为例，图2中的光201与准直器主光轴221的夹角为θ，该夹角θ为经过点O的入射光是否能够到达感光单元22的角度的临界值。
具体地，对于入射角度小于θ的光，如光200，其可以穿过准直器21而被下方的感光单元22所接收；对于入射角度大于θ的光，如光202或者光203，则被准直器21所阻挡，无法被下方的感光单元22所接收(在不考虑光202反射的情况下)。由此可见，θ越小，准直器的空间过滤能力越好。而影响θ角的一个重要因素是准直器中准直孔(亦称作透光通孔)的深宽比(Aspect Ratio，AR)，即图2中孔的深度t与孔径s之比。很显然，深宽比越大，θ越小，于是深宽比成为衡量准直器特性的一个重要指标。
由于准直器可以是一个单独的光学组件(分立式)，也可以是集成在图像传感器之中(集成式)。分立式准直器的优点是可获得高深宽比，例如通过TSV工艺制作的硅通孔；其缺点是成本较高。集成式准直器则是基于CMOS后道工艺中的金属层实现，优点是没有额外的工艺成本，但由于金属 层的厚度和开口尺寸均受工艺所限制，因而深宽比难以进一步做高。
为了解决现有准直器深宽比不够高的问题，尤其针对集成式的准直器，本申请提供一种新的光学准直器的结构及制作方法，能够有效增加深宽比，从而提高其空间过滤能力。
具体地，本申请实施例的光学准直器可以看作为多个子准直器组合而成，例如，其自下至上可以包括2N-1个子准直器，其中，N≥2，为了便于说明，下面将以图3至图14为例进行说明。
图3示出了根据本申请实施例的光学准直器30的剖面图，图4示出了根据本申请实施例的光学准直器30的俯视图，其中，图3是图4中虚线AA’指示的剖面图。具体地，本申请实施例的光学准直器自至上可以包括2N-1个子准直器，如图3所示，这里仅以N＝3为例进行说明，即图3中的光学准直器30包括5个子准直器。
其中，对于该光学准直器30的最下方的第一金属层301，在该第一金属层301上设置有准直孔，从而形成第一个子准直器31；类似的，在该第一金属层301的上方还设置有第二金属层303，在该第二金属层303上设置有准直孔，从而形成第三个子准直器33；另外，在该第一金属层301与该第二金属层303之间的介质层称为第一通孔层302，该第一通孔层302中设置有第一通孔，在该第一通孔内填充金属，以使得该填充了金属的第一通孔可以连接该第一金属层301与该第二金属层303，该第一通孔层302为第二个子准直器32。
依次类推，对于第i-1金属层与第i金属层之间为第i-1通孔层，该第i-1通孔层中设置有第i-1通孔，在该第i-1通孔内填充金属以连接该第i-1金属层与该第i金属层，该第i-1通孔层为第2i-2个子准直器，i依次取2,3,……N；在该第i金属层上设置准直孔形成第2i-1个子准直器，该第i金属层位于该第i-1金属层上方。
应理解，本申请实施例的光学准直器中包括的2N-1个子准直器是由金属层和通孔层交替形成的，其中，金属层形成的子准直器有N个，通孔层形成的子准直器有N-1个。例如，如图3和图4所示的光学准直器30包括5个子准直器，即N＝3，其中，金属层形成的子准直器有3个，通孔层形成的子准直器有2个，但本申请实施例并不限于此。
可选的，对于N个金属层中任意一个金属层，在该金属层上设置准直孔 进而形成子准直器，其中，该金属层的厚度可以根据实际应用进行设置，不同金属层的厚度可以设置为相同或者不同；该准直孔的形状可以根据实际应用任意设置；并且，每个金属层上包括的准直孔的个数也可以根据实际应用进行设置；另外，不同金属层上的准直孔的个数和形状可以相同，也可以不同，同一个金属层上具有多个准直孔时，不同准直孔的形状也可以相同或者不同。也就是说，任意一个金属层形成的子准直器可以包括一个或者多个准直孔，每个准直孔的形状可以根据实际应用进行设置，本申请实施例并不限于此。
例如，对于任意一个金属层而言，其准直孔的形状和个数可以如图5所示。具体地，图5为本申请实施例的光学准直器中任意一个金属层上准直孔的示意图，如图5所示，该金属层上可以包括一个或者多个准直孔。
其中，若该金属层仅包括一个准直孔，其可以为单孔型或者也可以为环型，若是单孔型，该准直孔可以为任意规则或者不规则的形状，例如图5示出的5种形状；若准直孔是环型，该环型也可以为任意规则或者不规则的形状，并且环型包括的内外两个形状也可以相同，也可以不同，例如图5示出的5种环型，但本申请实施例并不限于此。
另外，该金属层还可以包括多个准直孔，每个准直孔的形状可以相同，也可以不相同，并且该多个准直孔的排列方式也可以根据实际应用进行任意设置。例如，假设该金属层包括多个相同的圆形准直孔，则该多个准直孔的排列方式可以按照如图5所示的方式进行排列，但本申请实施例并不限于此。
由于每个金属层上设置的准直孔的形状不同，对应的准直孔的孔径以及中轴线的确定方式也可以不相同。例如，以任意一个金属层上的任意一个准直孔为例，若该准直孔为圆形，该准直孔的孔径为该圆形的直径，该准直孔的中轴线为穿过圆形的轴线；若该准直孔为正三角形，该准直孔的孔径可以为该正三角形的高，而该准直孔的中轴线可以设置为经过正三角形的三条高的交点的垂直轴线；若该准直孔为矩形或者其他多边形，该准直孔的孔径可以为该矩形或多边形的边长，或者也可以为该矩形或多边形的对角线长，而该矩形或者多边形的中轴线可以为经过对角线的交点的垂直轴线，本申请实施例并不限于此。
例如，图3和图4所示的光学准直器30，其中的各个金属层的准直孔均设置为圆形，则每个金属层对应的子准直器的准直孔的孔径为如图3和图4 所示的圆形的直径s，该准直孔的中轴线为经过该圆形圆心的轴线300。
可选的，若金属层上的准直孔为环型，例如圆环或者方环，或者其他形状的环型，该准直孔的孔径可以指该环型的环的宽度，该准直孔的中轴线可以指该环型的环的中线，或者，也可以指该环型内部图形的中轴线。例如，若该准直孔为圆环，该准直孔的孔径即为圆环的环的宽度，即内外两个圆形的半径之差；该圆环的中轴线可以指经过内部的圆形的圆心的轴线，或者也可以指该圆环的内外两个圆形之间的中线。若该准直孔为方环，该准直孔的孔径即为方环的环的宽度，即内外两个方形的边长之差的一半；该方环的中轴线可以指经过内部的方形的中心的轴线，或者也可以指该方环的内外两个方形之间的中线。
例如，图6示出了根据本申请实施例的光学准直器40的剖面图，图7示出了根据本申请实施例的光学准直器40的俯视图，其中，图6是图7中虚线BB’指示的剖面图。如图6和图7所示，该光学准直器40的各个金属层对应的子准直器的准直孔均为方环，则每个金属层对应的子准直器的准直孔的孔径为如图6和图7所示的方环的环的宽度s，同时s也等于内外两个方形的边长之差的一半。而该方环形准直孔的中轴线可以指内部方形的中线400，或者，也可以指内外两个方形之间的中线420，本申请实施例并不限于此。
应理解，若对于任意一个金属层，该金属层上设置多个准直孔，则每个准直孔的孔径以及中轴线的确定方式均可以按照上述单个准直孔的确定方式进行确定；另外，对于中轴线的确定方式也可以采用其他方式，例如，对于任意一个金属层，假设该金属层的准直孔为如图5中间多孔型所示的包括两个并列圆形，则该金属层的准直孔的中轴线也可以为经过该两个圆形的圆形连线中点的轴线，但本申请实施例并不限于此。
可选的，本申请实施例中的光学准直器可以包括多个金属层，若不同金属层包括不同形状的准直孔，则不同金属层的准直孔的孔径也可能不相同，中轴线也可能不同，其中每一层金属层的准直孔的孔径和中轴线可以按照其形状分别进行确定。其中，若多层金属层的准直孔形状相同，则采用相同的方式确定每一层的准直孔的孔径和中轴线。
例如，图8示出了根据本申请实施例的光学准直器50的剖面图，图9示出了根据本申请实施例的光学准直器50的俯视图，其中，图8是图9中 虚线CC’指示的剖面图。如图8和图9所示，第一金属层501的子准直器51的准直孔与第二金属层503的子准直器53的准直孔的形状相同，均为圆环，但第三金属层505的子准直器55的准直孔为圆形。其中，第一金属层501的子准直器51的准直孔与第二金属层503的子准直器53的准直孔的中轴线的确定方式相同，例如均可以设置为520，或者均设置为500；而第三金属层505的子准直器55的准直孔的中轴线可以设置为500。第一金属层501的子准直器51的准直孔与第二金属层503的子准直器53的准直孔的孔径均为s；而第三金属层505的子准直器55的准直孔的孔径为圆形的直径2s+d。
应理解，由于本申请实施例的光学准直器中每个金属层上均设置有准直孔，因此，可以将每个金属层分为准直孔区域和除准直孔以外的金属区域。
可选的，本申请实施例中的各个金属层的金属区域的材料可以为任意金属，并且不同金属层的材料可以相同，也可以不同。例如，对于任意一层金属层，其可以采用铝(Al)、铜(Cu)和氮化钛(TiN)等材料中的一种或多种。另外，本申请实施例中的金属层的准直孔区域以及其他介质填充区域310的材料可以根据实际应用进行设置，例如介质310可以为二氧化硅(SiO 2)和/或氮化硅(Si 3N 4)，但本申请实施例并不限于此。
应理解，本申请实施例中的两个金属层之间的通孔内设置有金属，可以用于连接上下两层金属层，其可以具体指：通孔连接上下两层金属层的金属区域。具体地，这里以图3和图4所示的光学准直器30中的第一金属层301与第二金属层303之间的第一通孔层302为例进行说明。由于该第一金属层301与第二金属层303上均设置有准直孔，这里称准直孔以外的区域为金属区域，则该第一通孔层302上设置的第一通孔连接该第一金属层301与该第二金属层303可以指：第一通孔连接该第一金属层301的金属区域与该第二金属层303的金属区域，也就是说该通孔顶部和底部仅与金属区域接触，而不接触非金属区域。
可选的，对于本申请实施例的光学准直器中N-1个通孔层中任意一个通孔层，其可以包括至少一个通孔，不同通孔层的厚度可以根据实际应用进行设置，不同通孔层的厚度可以设置为相同或者不同；并且，不同通孔层可以具有相同或者不同的通孔个数，并且每个通孔的形状可以根据实际应用进行任意设置。为了便于说明，这里以任意一个通孔层为例进行说明。
可选的，可以参照金属层的准直孔的形状，设置通孔层的通孔的形状。例如，如图4所示，光学准直器30中每个金属层的准直孔为圆形，则可以将各个通孔层中的通孔均设置为大于金属层的准直孔孔径的圆环，即将圆环的环形区域设置为通孔，在该环形区域内填充金属，以用于连接上下两层金属层。例如，如图3和图4设置通孔层的通孔，则该通孔层的准直孔的孔径等于金属层的准直孔的孔径s。
再例如，如图7所示，光学准直器40中每个金属层的准直孔为方环，则可以将通孔层中的通孔对应金属层准直孔内外两个方形而设置成两个方环，以便于分别连接上下两层金属层。例如，如图6和图7设置通孔层的通孔，则该通孔层的准直孔的孔径等于金属层的准直孔的孔径s。
可选的，通孔层的通孔还可以设置为与金属层的准直孔形状不对应的任意形状。例如，以图10或图11为例，参照图3可知，这里仍然假设每层金属层的准直孔为相同的圆形，则通孔层的通孔可以如图4所示的圆环形；或者，通孔层的通孔也可以为如图10所示的内部圆形外部方形的环状结构，即内部圆形外部方形的环状结构部分为该通孔层的通孔；或者，通孔层还可以设置为如图11所示的多个通孔，该多个通孔可以为任意形状和个数，排列在上下金属层的金属区域内，例如，如图11所示，通孔层302或304可以包括4个相同形状的通孔，平均排列在金属层的准直孔周围区域内，但本申请实施例并不限于此。
应理解，对于通孔层中不同形状的通孔，通孔层形成的子准直器的准直孔指的是该通孔层内除通孔以外的并且与在金属层形成的子准直器的准直孔相对应的部分。例如，如图4所示，该通孔层的子准直器的准直孔指的是通孔以外的、并且与上下金属层的准直孔位置一致的部分。
通孔层中形成的子准直器的准直孔的孔径的计算方式可以参照上述描述的金属层的子准直器的准直孔的孔径计算方式，为了简洁，在此不再赘述。
应理解，本申请实施例中的通孔层的通孔内填充金属，该金属的材料可以根据实际应用进行设置，例如，可以将该材料设置为钨和/或铜。
在本申请实施例中，光学准直器包括的2N-1个子准直器的准直孔的孔径可以相同，也可以不同。可选的，若不同子准直器的准直孔的孔径不相同，那么该光学准直器的通光量与孔径最小的子准直器相关。例如，如图3和图4所示，该2N-1个准直器的准直孔的孔径均设置为相同值s。再例如，如图 12所示，该光学准直器60与图3中的光学准直器30类似，同样包括5个子准直器，但该5个子准直器的准直孔不完全相同，此时，该光学准直器60的通光量与最小的准直孔相关。例如，如图12所示，假设第一个子准直器和第五个子准直器的准直孔的孔径最小且相等，均等于s，那么该光学准直器60的通光量与图3和图4的光学准直器30的通光量相等。
可选的，考虑到光学准直器的通光量，本申请实施例的光学准直器包括的2N-1个子准直器可以设置为满足如下条件：该第一个子准直器的准直孔孔径为该2N-1个子准直器的准直孔孔径的最小值，该第一个子准直器至该第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相等，n为正整数，2≤n≤N，第2j-3个子准直器的准直孔的中轴线与该第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
为了便于描述，下面将结合几个具体实施例，详细描述本申请实施例的几种光学准直器。
可选的，作为第一个实施例，对于中轴线的偏移距离为零，也就是预设值等于0，且n＝N的情况。具体地，该光学准直器包括2N-1个子准直器，该2N-1个子准直器中对应金属层的子准直器的准直孔的形状和尺寸均相同，并且这些准直孔的中轴线重合。
可选的，还可以将该2N-1个子准直器中对应的通孔层的子准直器的准直孔的形状和尺寸也设置为相同，并且这些准直孔的中轴线也设置为重合。
可选的，该2N-1个子准直器中通孔层对应的子准直器的准直孔的形状可以与金属层对应的子准直器的准直孔的形状相同，也可以不同；准直孔的孔径也可以相同或不同，例如可以设置通孔层对应的子准直器的准直孔的孔径大于金属层对应的子准直器的准直孔孔径；而通孔层对应的子准直器的准直孔的中轴线可以与金属层对应的子准直器的准直孔的中轴线设置为相同，或者存在偏移距离，本申请实施例并不限于此。
例如，考虑到光学准直器的效果，该第一个实施例中的光学准直器可以设置为如图3和图4所示的光学准直器30。具体地，该光学准直器30一共由三层金属层及两层通孔层所形成的5个子准直器所构成，如图3和图4所示，该光学准直器30包括：由第一金属层301形成的圆孔形准直孔的子准直器31，其孔径为s，深度为t；由第一通孔层302形成的圆孔形准直孔的 子准直器32，其孔径为s，深度为h；由第二金属层303形成的圆孔形准直孔的子准直器33，其孔径为s，深度为t；由第二通孔层304形成的圆孔形准直孔的子准直器34，其孔径为s，深度为h；由第三金属层305形成的圆孔形准直孔的子准直器35，其孔径为s，深度为t。
该五个子准直器31～35按照中心对称轴300重合的方式进行堆叠，即该光学准直器30的主光轴为300。因此，该光学准直器30的深宽比AR可以用以下公式(1)描述：
Figure PCTCN2019081153-appb-000001
相对于由单层金属层形成的准直器来说，该光学准直器30的深宽比显著提高。
在上述结构中，金属层301、303和305的材料可以是铝(Al)、铜(Cu)或氮化钛(TiN)等；在通孔层302和303中，通孔内的填充金属可以是钨(W)或铜(Cu)等，金属以外的其他区域则为金属间介质310所填充，该介质310的材料可以是二氧化硅(SiO 2)或者氮化硅(Si 3N 3)等。另外，该光学准直器30各层的具体制作方法可参考标准CMOS工艺，在此不再赘述。
再例如，该第一个实施例中的光学准直器还可以设置为如图6和图7所示的光学准直器40。具体地，相比于上述具有圆孔形准直孔的光学准直器40的透光通道为圆孔，准直器40的透光通道为方环，其好处就是既保证一定的滤光效果，同时又增大了进光量，从而可以提高单位时间内感光器件的响应。这种环形的准直器40同样是由三层金属层及两层通孔层所形成的尺寸相同的5个环形子准直器61～65所构成。并且，每层子准直器采用中心对称轴400重合的方式依次堆叠，故其深宽比同样为上述公式(1)所示。因其结构与准直器30基本类似，在此不再赘述。
可选的，作为第二个实施例，光学准直器满足：中轴线的偏移距离为零，也就是预设值等于0，且n小于N的情况。具体地，该光学准直器中第一个子准直器至第2n-1个子准直器满足：该2n-1个子准直器中对应金属层的子准直器的准直孔的形状和尺寸均相同，并且这些准直孔的中轴线重合。
可选的，还可以将该2n-1个子准直器中对应的通孔层的子准直器的准直孔的形状和尺寸也设置为相同，并且这些准直孔的中轴线也设置为重合。
可选的，该2n-1个子准直器中通孔层对应的子准直器的准直孔的形状 可以与金属层对应的子准直器的准直孔的形状相同，也可以不同；准直孔的孔径也可以相同或不同，例如可以设置通孔层对应的子准直器的准直孔的孔径大于金属层对应的子准直器的准直孔孔径；而通孔层对应的子准直器的准直孔的中轴线可以与金属层对应的子准直器的准直孔的中轴线设置为相同，或者存在偏移距离，本申请实施例并不限于此。
另外，对于第2n个子准直器至第2N-1个子准直器，可以参照该2n-1个子准直器进行设置，可选的，也可以设置为准直孔的形状和尺寸均相同，并且这些准直孔的中轴线重合的情况。
例如，图8和图9示出了一种高深宽比的复合型准直器50的结构。该复合型准直器50的透光通道的上部为孔，下部为环形，采用这种复合结构可以进一步增加深宽比。这种复合结构的准直器50是由三层金属层及两层通孔层所形成的3个环型子准直器加2个孔型子准直器所构成，即取N＝3，n＝2。具体地，该复合型准直器50包括：第一金属层501形成的圆环形准直孔的子准直器51，其主光轴为520，环形透光通道尺寸为s，深度为t；由第一通孔层502形成的圆环形准直孔的子准直器52，其主光轴为520，环形透光通道尺寸为s，深度为h；由第二金属层503形成的圆环形准直孔的子准直器53，其主光轴为520，环形透光通道尺寸为s，深度为t；由第二通孔层504形成的圆孔形准直孔的子准直器54，其主光轴为500，孔径为2s+d，深度为h；由第三金属层505形成的圆孔形准直孔的子准直器55，其主光轴为500，孔径为2s+d。
由于第三金属层为厚度为4t的顶层金属(top metal)，故子准直器55其深度为4t。子准直器51～55按照中心对称轴500重合的方式依次堆叠，通过计算可知准直器50的深宽比为：
Figure PCTCN2019081153-appb-000002
此外，复合型准直器50的透光通道结构还可以有其他形式的组合，例如，该复合型准直器可以为上部的大孔和下部若干小孔的组合，或者，还可以为上部大方孔，下部为小圆孔或环型孔，本申请实施例并不限于此。
可选的，作为第三个实施例，对于中轴线的偏移距离不为零，也就是预设值不等于0，且n＝N的情况。具体地，本申请实施例中的光学准直器还可以为斜孔的准直器，即该准直器包括的子准直器之间可以在某一预定方向上 具有一定的偏移距离。具体地，对于光学准直器包括的2N-1个子准直器，该2N-1个子准直器中对应任意相邻的两个金属层的子准直器的准直孔可以满足：该两个准直孔的中轴线沿着预设方向偏移预设距离。
可选的，对于该任意两个金属层之间的通孔层，也可以满足该偏移距离的设置，即该2N-1个子准直器中该第2j-3个子准直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为该预设方向，且偏移距离为该预设值的一半。
例如，图13示出了一种斜孔型准直器70的结构，其截面图如图7所示。具体地，该准直器70包括：由第一金属层701形成的圆孔形准直孔的子准直器71，其孔径为s，深度为t；由第一通孔层702形成的圆孔形准直孔的子准直器72，其孔径为w，深度为h，子准直器72的中轴线相对于子准直器71的中轴线向右方的偏移距离721为0.5*(h+t)tanθ；由第二金属层703形成的圆孔形准直孔的子准直器73，其孔径为s，深度为t，子准直器73中轴线相对于子准直器72中轴线向右方的偏移距离732也为0.5*(h+t)tanθ；由第二通孔层704形成的圆孔形准直孔的子准直器74，其孔径为w，深度为h，子准直器74中轴线相对于子准直器73中轴线向右方的偏移距离743为0.5*(h+t)tanθ；由第三金属层705形成的圆孔形准直孔的子准直器75，其孔径为s，深度为t，子准直器75中轴线相对于子准直器74中轴线向右方的偏移距离754仍然为0.5*(h+t)tanθ。
采用这种堆叠子准直器的方式可以获得主光轴相对于入射面法线的夹角呈θ角度的准斜孔准直器70，该准斜孔准直器70可以对入射角为θ的倾斜入射光起到一定的空间过滤效果。
可选的，本申请实施例中对于中轴线的偏移距离不为零，也就是预设值不等于0的情况，也可以设置n小于N，也就是将光学准直器50与光学准直器70相结合，为了简洁，在此不再赘述。
在本申请实施例中，该光学准直器可以为一个单独的光学组件(分立式)，也可以是集成在图像传感器之中(集成式)。例如，本申请实施例中的光学准直器可以应用于如图1所示的指纹指标模组中，该光学准直器可以单独设置，或者，也可以集成到CMOS图像传感器上。
例如，图14示出了一种将准直器80集成到CMOS图像传感器上的情况。如图14所示，这里假设准直器80由两层金属层及一层通孔层所形成的 3个圆孔形准直孔子准直器所构成，该准直器80包括：第一金属层801形成的子准直器81，其孔径为s，深度为t；第一通孔层802形成的子准直器82，其孔径为s，深度为h；第二金属层803形成的子准直器83，其孔径为s，由于第二金属层为顶层金属，其厚度可以为4t，因而子准直器83的准直孔深度为4t。子准直器81、82及83的孔径均为s，且主光轴均为同一根光轴800，因此，准直器80的深宽比为：
Figure PCTCN2019081153-appb-000003
光在经过由多个准直器80所形成的准直器阵列时，高深宽比准直器可以将来自非指纹反射的屏幕杂散光很好地滤除，而携带指纹信息的反射光则可以通过准直器继而被图像传感器上的感光单元820吸收，最终输出得到高信噪比的图像。
因此，本申请实施例的光学准直器，通过设置多层金属层，从而形成多层子准直器构成的光学准直器，能够解决现有集成式准直器深宽比难以提升的问题，有效增加了深宽比，从而提高其空间过滤能力。
下文将将结合图15，详细描述本申请实施例的光学准直器的制作方法900。具体地，图15示出了根据本申请实施例的光学准直器的制作方法900的示意性流程图，如图15所示，该方法900包括：S910，在第一金属层上设置准直孔，以形成第一个子准直器；S920，在第二金属层上设置准直孔，以形成第三个子准直器，该第二金属层位于该第一金属层上方；S930，在第i-1金属层与第i金属层之间的第i-1通孔层中设置第i-1通孔，并在该第i-1通孔内填充金属，以连接该第i-1金属层与该第i金属层，该第i-1通孔层为第2i-2个子准直器，i依次取2,3,……N，N为大于1的正整数；S940，在该第i金属层上设置准直孔，以形成第2i-1个子准直器，该第i金属层位于该第i-1金属层上方。
应理解，该方法900可以用于制作本申请实施例中的光学准直器，例如，可以用于制作本申请实施例中的光学准直器30-80中任意一个光学准直器。
可选的，作为一个实施例，该光学准直器的2N-1个子准直器中该第一个子准直器至第2n-1个子准直器满足：该第一个子准直器的准直孔孔径为该2N-1个子准直器的准直孔孔径的最小值，该第一个子准直器至该第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相 等，n为正整数，2≤n≤N，第2j-3个子准直器的准直孔的中轴线与该第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
可选的，作为一个实施例，该第一个子准直器至该第2n-1个子准直器的准直孔的形状相同。
可选的，作为一个实施例，该预设值为零。
可选的，作为一个实施例，n＝N。
可选的，作为一个实施例，该2N-1个子准直器的准直孔孔径相等。
可选的，作为一个实施例，该预设值大于零。
可选的，作为一个实施例，该第2j-3个子准直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为该预设方向，且偏移距离为该预设值的一半。
因此，本申请实施例的光学准直器的制作方法，通过设置多层金属层，从而形成多层子准直器构成的光学准直器，能够解决现有集成式准直器深宽比难以提升的问题，有效增加了深宽比，从而提高其空间过滤能力。
应理解，本申请实施例的光学准直器可以应用于光学指纹识别模组中，具体地，该光学指纹识别模组可以包括本申请实施例的光学准直器以及图像传感器，其中，该图像传感器设置在该光学准直器的下方，该光学准直器用于：过滤经过手指反射的返回光并汇聚至该图像传感器；该图像传感器用于：接收经过该光学准直器的该返回光并根据接收到的该返回光生成指纹数据，该指纹数据用于对该手指进行指纹识别。
例如，该光学指纹识别模组可以如图1所示，其中，光学准直器14为本申请实施例中的光学准直器，例如，可以为光学准直器30-80中任意一个光学准直器。
可选的，该光学准直器14可以为一个单独的光学组件(分立式)，也可以是集成在图像传感器之中(集成式)。例如，如图14所示，该光学准直器80集成在图像传感器820上。
可选的，该光学指纹识别模组还可以包括：光源，用于产生光，该光用于照亮该手指并反射产生该返回光。
应理解，上述光学指纹识别模组可以应用于终端设备中，具体地，该终端设备可以包括：显示屏，用于为手指提供触摸界面；光学指纹识别模组， 位于该显示屏下方，用于对该手指进行指纹识别。
可选的，该显示屏还可以用作光源，例如，该显示屏还可以包括：发光显示像素，用于显示图像以及发光，该光用于照亮该手指并反射产生该返回光。
例如，如图1所示，该图1示出了该终端设备的一部分，即该终端设备中与光学准直器14、图像传感器13相对应的部分，该终端设备还包括显示屏11，但本申请实施例并不限于此。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请 的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(read-only memory，ROM)、随机存取存储器(random access memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (23)

  1. 一种光学准直器，其特征在于，所述光学准直器包括2N-1个子准直器，N为大于1的正整数，
    其中，第一金属层上设置有准直孔，形成所述2N-1个子准直器中的第一个子准直器；
    第二金属层上设置有准直孔，形成所述2N-1个子准直器中的第三个子准直器，所述第二金属层位于所述第一金属层上方；
    第i-1金属层与第i金属层之间为第i-1通孔层，所述第i-1通孔层中设置有第i-1通孔，填充金属的所述第i-1通孔用于连接所述第i-1金属层与所述第i金属层，所述第i-1通孔层为所述2N-1个子准直器中的第2i-2个子准直器，i依次取2,3,……N；
    所述第i金属层上设置有准直孔，形成所述2N-1个子准直器中的第2i-1个子准直器，所述第i金属层位于所述第i-1金属层上方。
  2. 根据权利要求1所述的光学准直器，其特征在于，所述2N-1个子准直器中所述第一个子准直器至第2n-1个子准直器满足：
    所述第一个子准直器的准直孔孔径为所述2N-1个子准直器的准直孔孔径的最小值，所述第一个子准直器至所述第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相等，n为正整数，2≤n≤N，
    第2j-3个子准直器的准直孔的中轴线与所述第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
  3. 根据权利要求2所述的光学准直器，其特征在于，所述第一个子准直器至所述第2n-1个子准直器的准直孔的形状相同。
  4. 根据权利要求2或3所述的光学准直器，其特征在于，所述预设值为零。
  5. 根据权利要求4述的光学准直器，其特征在于，n＝N。
  6. 根据权利要求5述的光学准直器，其特征在于，所述2N-1个子准直器的准直孔孔径相等。
  7. 根据权利要求2或3所述的光学准直器，其特征在于，所述预设值大于零。
  8. 根据权利要求7述的光学准直器，其特征在于，所述第2j-3个子准 直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为所述预设方向，且偏移距离为所述预设值的一半。
  9. 根据权利要求1至8中任一项所述的光学准直器，其特征在于，所述第一金属层以及所述第i金属层的材料为以下材料中的至少一种：铝、铜和氮化钛。
  10. 根据权利要求1至9中任一项所述的光学准直器，其特征在于，所述第i-1通孔层中通孔内填充的金属的材料为钨和/或铜。
  11. 根据权利要求1至10中任一项所述的光学准直器，其特征在于，所述光学准直器的准直孔内的填充材料为二氧化硅和/或氮化硅。
  12. 一种光学准直器的制作方法，其特征在于，所述方法包括：
    在第一金属层上设置准直孔，以形成第一个子准直器；
    在第二金属层上设置准直孔，以形成第三个子准直器，所述第二金属层位于所述第一金属层上方；
    在第i-1金属层与第i金属层之间的第i-1通孔层中设置第i-1通孔，并在所述第i-1通孔内填充金属，以连接所述第i-1金属层与所述第i金属层，所述第i-1通孔层为第2i-2个子准直器，i依次取2,3,……N，N为大于1的正整数；
    在所述第i金属层上设置准直孔，以形成第2i-1个子准直器，所述第i金属层位于所述第i-1金属层上方。
  13. 根据权利要求12所述的制作方法，其特征在于，所述光学准直器的2N-1个子准直器中所述第一个子准直器至第2n-1个子准直器满足：
    所述第一个子准直器的准直孔孔径为所述2N-1个子准直器的准直孔孔径的最小值，所述第一个子准直器至所述第2n-1个子准直器中在金属层上形成的子准直器的准直孔的形状相同且孔径均相等，n为正整数，2≤n≤N，
    第2j-3个子准直器的准直孔的中轴线与所述第2j-1个子准直器的准直孔的中轴线之间的偏移方向为预设方向且偏移距离为预设值，j为正整数，j依次取2,3,……n。
  14. 根据权利要求13所述的制作方法，其特征在于，所述第一个子准直器至所述第2n-1个子准直器的准直孔的形状相同。
  15. 根据权利要求13或14所述的制作方法，其特征在于，所述预设值为零。
  16. 根据权利要求15所述的制作方法，其特征在于，n＝N。
  17. 根据权利要求16所述的制作方法，其特征在于，所述2N-1个子准直器的准直孔孔径相等。
  18. 根据权利要求13或14所述的制作方法，其特征在于，所述预设值大于零。
  19. 根据权利要求18所述的制作方法，其特征在于，所述第2j-3个子准直器的准直孔的中轴线与第2j-2个子准直器的准直孔的中轴线之间的偏移方向为所述预设方向，且偏移距离为所述预设值的一半。
  20. 一种光学指纹识别模组，其特征在于，包括：如权利要求1至11中任一项所述的光学准直器以及图像传感器，
    所述图像传感器设置在所述光学准直器的下方，
    所述光学准直器用于：过滤经过手指反射的返回光并汇聚至所述图像传感器；
    所述图像传感器用于：接收经过所述光学准直器的所述返回光并根据接收到的所述返回光生成指纹数据，所述指纹数据用于对所述手指进行指纹识别。
  21. 根据权利要求20所述的光学指纹识别模组，其特征在于，所述光学指纹识别模组还包括：
    光源，用于产生光，所述光用于照亮所述手指并反射产生所述返回光。
  22. 一种终端设备，其特征在于，包括：
    显示屏，用于为手指提供触摸界面；
    如权利要求20或21所述的光学指纹识别模组，位于所述显示屏下方，用于对所述手指进行指纹识别。
  23. 根据权利要求22所述的终端设备，其特征在于，所述显示屏包括：
    发光显示像素，用于显示图像以及发光，所述光用于照亮所述手指并反射产生所述返回光。
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