Patent Publication Number: US-11646339-B2

Title: Image pickup element, image pickup device, manufacturing device and method

Description:
TECHNICAL FIELD 
     The present technology relates to image pickup elements, image pickup devices, manufacturing devices and methods, and more particularly, to an image pickup element, image pickup device, manufacturing device and method which can reduce deterioration of sensitivity characteristics. 
     BACKGROUND ART 
     Conventionally, a solid-state image pickup device, which includes a large number of image pickup regions, and an optical element having microlenses etc., on a semiconductor wafer, is hermetically molded after electrical interconnects have been formed, and is used as a photosensor for digital video equipment, such as a digital still camera, a camera for a mobile telephone, a digital camcorder, etc. 
     Various methods have been proposed as a method for manufacturing such a solid-state image pickup device (see, for example, Patent Literature 1 and Patent Literature 2). 
     Patent Literature 1 discloses a method for manufacturing a microlens in which a gap between each microlens made of inorganic film is reduced, and a distance from a photodiode to the microlens is reduced, thereby improving sensitivity characteristics of a solid-state image pickup element. 
     Patent Literature 2 discloses a method for manufacturing a microlens including two layers. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2008-009079A 
     Patent Literature 2: JP 2008-277800A 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the case of the method described in Patent Literature 1, a middle layer is also used to transfer its shape to a lens material layer by etching, and therefore, it takes a longer time to perform the etching. This etching process is performed by plasma etching, and therefore, the plasma damage adversely affects the solid-state image pickup device. Specifically, dark-current characteristics etc. of the solid-state image pickup element deteriorate due to the longer etching time. At the same time, the long processing time increases variations in etching on a semiconductor wafer substrate surface or between wafer substrates, which causes variations in the position in the cross-sectional direction of the microlens, leading to the risk of reduction of the sensitivity characteristics of the solid-state image pickup element. 
     The microlens with high light collection power which is formed by the method described in Patent Literature 2 is a gapless microlens which is formed by adjusting the film formation of the microlens in the second layer so that there is not a gap between each microlens. However, when the micro in the second layer is formed so that a gap of the microlens in the first layer having a gap is reduced, the position of the microlens which is finally formed is raised (further away from the photodiode surface), and therefore, it is likely that the sensitivity characteristics etc. of a solid-state image pickup device in which the distance between the photodiode and the microlens is reduced as in, for example, a back-illuminated solid-state image pickup device, cannot be improved. 
     With these circumstances in mind, the present technology has been proposed, and it is an object of the present technology to reduce the deterioration of the sensitivity characteristics. 
     Solution to Problem 
     According to a first aspect of the present technology, there is provided an image pickup element including a non-planar layer having a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on a side of the light incident surface of the non-planar layer, and collects incident light. 
     The microlens may include a plurality of layers. 
     The layers of the microlens including the plurality of layers may have different refractive indices. 
     The layers of the microlens including the plurality of layers may have different curved surface shapes. 
     At least a portion of the layers of the microlens including the plurality of layers may be formed in a recess portion of the non-planar layer. 
     An anti-reflection film may be formed over a light incident surface of the microlens. 
     An adhesive material layer provided on a side of a light incident surface of the microlens may be further included. 
     The non-planar layer may have a filter. 
     The filter may include filters with a plurality of colors having different thicknesses in a direction in which light passes. 
     In the filter, filters having different thicknesses and corresponding to red, green, and blue pixels, may be arranged in a Bayer arrangement, and the green filters may be linked between pixels. 
     The filter may be formed of an organic material. 
     The non-planar layer may have an organic film which is formed on the filter and has a non-planar light incident surface. 
     Heights of projections and recesses of a light incident surface of the organic film may be lower than heights of projections and recesses of a light incident surface of the filter. 
     The refractive index of the organic film may be between the refractive index of the filter and the refractive index of the microlens. 
     The non-planar layer may have an inter-pixel light shield film. 
     The non-planar layer may have projections and recesses on the light incident surface due to a difference in height between the filter and the inter-pixel light shield film. 
     A chip size package structure may be formed. 
     According to a second aspect of the present technology, there is provided an image pickup device including an image pickup element which captures an image of an object, and outputs the image of the object as an electrical signal, and an image processing unit which processes the image of the object obtained by the image pickup element. The image pickup element includes a non-planar layer which has a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on a side of the light incident surface of the non-planar layer, and collects incident light. 
     According to a third embodiment of the present technology, there is provided a manufacturing device including a non-planar layer forming unit which forms a non-planar layer having a non-planar light incident surface in a light receiving region of an image pickup element, an inorganic film forming unit which forms an inorganic film on a side of the light incident surface of the non-planar layer formed by the non-planar layer forming unit, a planarization film forming unit which forms a planarization film on a side of a light incident surface of the inorganic film formed by the inorganic film forming unit, a resist forming unit which forms a resist on a side of a light incident surface of the planarization film formed by the planarization film forming unit, a thermal reflow process unit which performs a thermal reflow process on the image pickup element on which the resist has been formed by the resist forming unit, and an etching process unit which performs etching on the image pickup element on which the thermal reflow process has been performed by the thermal reflow process unit. 
     According to the third embodiment of the present disclosure, there is further provided a method for manufacturing a manufacturing device which manufactures an image pickup element, the method including by the manufacturing device, forming a non-planar layer having a non-planar light incident surface in a light receiving region of an image pickup element, forming an inorganic film on a side of the light incident surface of the non-planar layer formed, forming a planarization film on a side of a light incident surface of the inorganic film formed, forming a resist on a side of a light incident surface of the planarization film formed, performing a thermal reflow process on the image pickup element on which the resist has been formed, and performing etching on the image pickup element on which the thermal reflow process has been performed. 
     According to the first aspect of the present technology, a non-planar layer having a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on the light incident surface of the non-planar layer, and collects incident light, are included. 
     According to the second aspect of the present technology, an image pickup element which captures an image of an object, and outputs the image of the object as an electrical signal, and an image processing unit which processes the image of the object obtained by the image pickup element, are included. The image pickup element includes a non-planar layer which has a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on the light incident surface of the non-planar layer, and collects incident light. 
     According to the third aspect of the present technology, a non-planar layer is formed which has a non-planar light incident surface in a light receiving region of an image pickup element, an inorganic film is formed on the light incident surface of the non-planar layer formed, a planarization film is formed on a light incident surface of the inorganic film formed, a resist is formed on a light incident surface of the planarization film formed, a thermal reflow process is performed on the image pickup element on which the resist has been formed, and etching is performed on the image pickup element on which the thermal reflow process has been performed. 
     Advantageous Effects of Invention 
     According to the present technology, deterioration of the sensitivity characteristics can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  2    is a diagram for describing a shift of an in-focus position. 
         FIG.  3    is a diagram showing an example main configuration of an image pickup device. 
         FIG.  4    is a diagram showing an example configuration of color filters. 
         FIG.  5    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  6    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  7    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  8    is a diagram showing an example configuration of a multi-layer microlens. 
         FIG.  9    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  10    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  11    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  12    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  13    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  14    is a diagram showing an example of each layer of a multilayer microlens. 
         FIG.  15    is a block diagram showing an example main configuration of a manufacturing device. 
         FIG.  16    is a flowchart for describing an example flow of a manufacture process. 
         FIG.  17    is a diagram for describing how a manufacture process is performed. 
         FIG.  18    is a diagram for describing an example film pressure ratio. 
         FIG.  19    is a diagram for describing an example mean free path. 
         FIG.  20    is a diagram for describing example spherical surface correction. 
         FIG.  21    is a diagram showing an example in which an anti-reflection film is applied. 
         FIG.  22    is a diagram for describing an example refractive index of an adhesive agent. 
         FIG.  23    is a diagram showing an example in which an inter-pixel light shield film is applied. 
         FIG.  24    is a diagram showing an example in which an inter-pixel light shield film is applied. 
         FIG.  25    is a block diagram showing another example configuration of a manufacturing device. 
         FIG.  26    is a flowchart for describing another example flow of a manufacture process. 
         FIG.  27    is a diagram for describing another example of how a manufacture process is performed. 
         FIG.  28    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  29    is a block diagram showing still another example configuration of a manufacturing device. 
         FIG.  30    is a flowchart for describing still another example flow of a manufacture process. 
         FIG.  31    is a diagram for describing still another example of how a manufacture process is performed. 
         FIG.  30    is a diagram showing an example configuration of a portion of the layers of an image pickup element. 
         FIG.  33    is a diagram showing an example configuration of a portion of an image pickup element. 
         FIG.  34    is a block diagram showing an example main configuration of an image pickup device. 
         FIG.  35    is a block diagram showing an example main configuration of a computer. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments for carrying out the present disclosure (hereinafter referred to as embodiments) will now be described. Note that the description will be given in the following order. 
     1. First Embodiment (Image Pickup Device) 
     2. Second Embodiment (Manufacturing Device, Manufacturing Method) 
     3. Third Embodiment (Manufacturing Device, Manufacturing Method) 
     4. Fourth Embodiment (Image Pickup Device) 
     5. Fifth Embodiment (Computer) 
     1. First Embodiment 
     [1-1 CSP] 
     A solid-state image pickup device, which includes a large number of image pickup regions, and an optical element having microlenses etc., on a semiconductor wafer, is hermetically molded after electrical interconnects have been formed, and is used as a photosensor for digital video equipment, such as a digital still camera, a camera for a mobile telephone, a digital camcorder, etc. 
       FIG.  1    shows an example configuration of microlenses and color filters in a solid-state image pickup element. In the example of  FIG.  1   , filters having different colors of the color filters have different thicknesses, and therefore, projections and recesses are formed on the light incident surface of the color filters Therefore, a planarization film is formed on the light incident surface to planarize the light incident surface. The microlenses are formed on the light incident surface of the planarization film. 
     Cross-sectional views shown in A of  FIG.  1    and B of  FIG.  1    have different cross-sectional directions. A thickness from the bottom surface of the color filter to the bottom surface of the microlens in the cross-sectional view shown in A of  FIG.  1    is t 1 , and a thickness from the bottom surface of the color filter to the bottom surface of the microlens in the cross-sectional view shown in B of  FIG.  1    is t 2 . 
     In order to achieve the recent smaller size, thinner size, and higher-density implementation of video equipment, the chip size package (CSP) technique, which is a technique of establishing electrical connections by forming through electrodes and redistribution lines during an assembly process on the wafer, has been studied as the structure of a solid-state image pickup device, instead of the ceramic-type or plastic-type package, in which electrical connections are established by traditional die bonding and wire bonding. 
       FIG.  2    shows how incident light is collected by a microlens, passes through the color filter, and focused onto the photodiode. From the viewpoint of the light collection characteristics, the refractive indices of the microlens and an adhesive material  1  are required to satisfy the following relationship. 
     Microlens&gt;Adhesive Material  1   
     As shown in  FIG.  2   , the incident light to the solid-state image pickup element includes perpendicular incident light and oblique incident light containing a perpendicular component and an oblique component. The light collection characteristics with respect to the perpendicular incident light to the photodiode can be adjusted by changing the radius of curvature (r) of the arc-shaped microlens. However, for the oblique incident light, the focus position of the perpendicular incident light is shifted. In order to reduce the amount of the shift, it is necessary to reduce the layer thickness. By reducing the layer thickness to adjust the radius of curvature of the microlens, the sensitivity characteristics or luminance shading of the solid-state image pickup element are improved. 
     When the CSP structure is employed as the package structure of a solid-state image pickup element, there is typically an empty space on the microlens. The refractive index of the microlens is about 1.50 to 1.6 when the microlens is made of a typical resin, such as an acrylic-based resin or a styrene-based resin. Therefore, the light collection characteristics are determined, from the refractive index of 1.0 of air, by the microlens having a refractive index of about 1.5 to 1.6 (the refractive index difference Δn: about 0.5 to 0.6). 
     However, when the CSP structure is employed, then if the adhesive material  1  formed on the microlens contains fluorine in its acrylic-based resin or siloxane-based resin, the refractive index is about 1.4 to 1.43. Alternatively, when the acrylic-based resin or the siloxane-based resin contains hollow silica, the refractive index is about 1.3 to 1.4. Here, when the microlens is made of a material of about 1.5 to 1.6 as described above, Δn is about 0.07 to 0.3, and therefore, the light collection power of the microlens is likely to decrease. If the light collection power decreases, the focal length of the microlens increases, and therefore, it is necessary to increase the layer thickness of  FIG.  2   , leading to the risk of deterioration of the sensitivity characteristics of the solid-state image pickup element having the increased thickness. 
     As described above, when the adhesive material  1  is made of a material having a refractive index of about 1.3 to 1.43, it is necessary to set the refractive index of the microlens to about 1.8 to 2.03 in order to achieve light collection power similar to when the CSP structure is not employed (there is air on the microlens). The microlens is also required to have high transparency with respect to visible light (400 to 700 nm). There is not a single organic material which has these characteristics in terms of refractive index and transparency. In contrast to this, a refractive index which can be improved by adding fine particles of a metal oxide, such as, for example, zinc oxide, zirconium oxide, niobium oxide, titanium oxide, tin oxide, etc., into a polyimide-based resin, a siloxane-based resin, a phenol-based resin, etc., can be adjusted based on the amount of the fine metal oxide particles which are added, and can be adjusted to about 1.6 up to about 2.0. 
     In addition the above technique of adding fine particles of a metal oxide into an organic material, silicon oxynitride film (SiON) or silicon nitride film (SiN), which are typically used in semiconductor manufacturing processes, can be used as a material which has both a refractive index and transparency. 
     However, when inorganic film, such as silicon oxynitride film (SiON) or silicon nitride film (SiN) etc., is used as a material for the microlens, the microlens is likely to be displaced at an interface between the inorganic film containing the microlens material and the organic film formed below the inorganic film due to the difference in thermal expansion coefficient etc. (thermal expansion coefficient: the inorganic film&lt;the organic film), depending on a thermal treatment step in the manufacturing process of the solid-state image pickup device after the formation of the microlens, or environmental conditions (particularly, high temperature, high humidity) after the manufacture of the solid-state image pickup device is completed. If the displacement occurs, the sensitivity characteristics or color non-uniformity characteristics of the solid-state image pickup device is likely to vary, leading to deterioration of image quality. 
     Therefore, in order to achieve a smaller size, thinner size, and higher-density implementation of video equipment, a wafer-level CSP is newly devised and implemented as the structure of a solid-state image pickup device, in order to achieve sensitivity characteristics which are greater than or equal to those of conventional packages in which air is present on a conventional microlens even if an adhesive material is provided on the microlens. A feature of the wafer-level CSP is that a microlens including a plurality of layers of inorganic film, such as SiON, SiN, SiO, etc., which is formed, corresponding to each light receiving region of the solid-state image pickup element, is formed on an underlying film which has a projection-and-recess shape at least due to the color filters. The microlenses are formed directly on the color filters which have a projection-and-recess shape, or on a non-planar film formed on the color filters which have a projection-and-recess shape. Also, the projection-and-recess shape can prevent the displacement of the microlens, whereby a structure of a solid-state image pickup device which does not have deterioration of image quality and has high reliability, and a method for manufacturing the solid-state image pickup device, are provided. 
     Note that Patent Literatures 1 and 2 disclose methods for manufacturing a microlens made of inorganic film, such as SiN, SiON, etc. 
     Patent Literature 1 discloses a method for manufacturing a microlens which has a reduced gap between each microlens made of inorganic film and a reduced distance between the photodiode and the microlens, thereby improving the sensitivity characteristics of a solid-state image pickup element. 
     In the method described in Patent Literature 1, which is a microlens manufacturing method, a thermal mask layer (a material layer which will be a microlens) made of an organic material which is formed in the top portion is deformed by a thermal treatment to form a microlens shape which has a gap between each microlens. A lens material layer (a layer which will be a microlens) made of an inorganic material is formed below the thermal mask layer, and thereafter, a middle layer made of an organic material is provided between this mask layer and the lens material layer. Patent Literature 1 discloses that, after etching the middle layer under predetermined conditions into a mask layer having a microlens shape having a gap between each microlens to provide a greater middle layer lens shape (a reduced microlens gap), the lens material layer made of an inorganic material, a microlens gap, is etched using the middle layer as a mask, whereby a microlens having an extremely reduced gap between each microlens can be formed. 
     Also, Patent Literature 1 discloses that SiN and SiOSiON are applicable to the lens material layer made of an inorganic material. In this case, when SiN or SiON is selected as this material layer, the light collection power of the microlens is improved, and at the same time, the gap between each microlens is reduced, and the distance from the photodiode to the microlens is reduced by transferring the mask layer to the middle layer by etching and further continuing the etching, thereby improving the light collection efficiency of the microlens. 
     However, because the shape is further transferred to the lens material layer through the middle layer by etching, it is likely to take a longer time to perform etching. This etching process is performed by plasma etching, and therefore, the plasma damage is likely to adversely affect the solid-state image pickup device. Specifically, the dark-current characteristics etc. of the solid-state image pickup element is likely to deteriorate due to the longer etching time. At the same time, the longer processing time also increases variations in etching on a semiconductor wafer substrate surface or between wafer substrates, which is likely to cause variations in the position in the cross-sectional direction of the microlens, leading to an adverse influence on the sensitivity characteristics etc. of the solid-state image pickup element. Moreover, in addition to the processing time of the etching device due to the longer wafer processing time, the formation of the middle layer increases the number of steps, leading to the risk of an increase in cost. 
     Moreover, Patent Literature 1 describes the color filters, but not the number of the colors. In the microlens manufacturing method including the long-time etching, it is likely to be difficult to adjust the position in the height direction of the bottom portion of the microlens. 
     Also, Patent Literature 2 discloses a method for manufacturing a microlens including two layers. In the microlens disclosed in Patent Literature 2, SiO, SiN, or SiON is used as an inorganic material. Typically, the refractive index of SiN is about 1.85 to 2.0, and the refractive index of SiON is about 1.6 to 1.8. Therefore, these are higher than the refractive index (about 1.5 to 1.6) of an acrylic-based resin or a styrene-based resin which is typically used in a microlens, and therefore, can improve the light collection power of the microlens. 
     Such a microlens with high light collection power is a gapless microlens which is formed by adjusting the film formation of the microlens in the second layer so that there is not a gap between each microlens. However, when the micro in the second layer is formed so that a gap of the microlens in the first layer having a gap is reduced, the position of the microlens which is finally formed is raised (further away from the photodiode surface), and therefore, it is likely that the sensitivity characteristics etc. of a solid-state image pickup device in which the distance between the photodiode and the microlens is reduced as in, for example, a back-illuminated solid-state image pickup device, cannot be improved. 
     Moreover, Patent Literature 2 discloses that the inorganic material used in the microlens in the first layer and the microlens in the second layer can be selected from SiO, SiN, and SiON, but does not disclose the refractive index of each layer or the relationship between the film thicknesses of the layers. 
     In order to improve the light collection characteristics of a microlens, it is necessary to consider the reduction of the gap between each lens and the distance from the photodiode (the layer thickness of  FIG.  2   ), and in addition to these, the surface reflectance. However, Patent Literature 2 does not disclose this relationship. Therefore, for example, when SiO, which has a low refractive index, is selected as a material for the microlens in the first layer, and SiON, which has a high refractive index, is selected as a material for the microlens in the second layer, the surface reflection of the microlens increases, leading to the risk of deterioration of the sensitivity characteristics of a solid-state image pickup device. 
     Moreover, Patent Literature 2 discloses that the microlens should be formed on a planarized surface. Patent Literature 2 discloses that the reason is to remove the level difference caused by the color filters, and that a planarization layer is formed on the color filters. Also, the planarization layer may not be formed. This seems to refer to the case where there is not a level difference caused by the color filters. Also, Patent Literature 1 does not describe a planarization film on the color filters. As shown in FIG. 1 of Patent Literature 1, a monochromatic color filter structure is shown, and therefore, it seems that there is not a level difference caused by the color filters. 
     As described above, in both Patent Literature 1 and Patent Literature 2, color filters are included, and an interface between a planarization film made of organic film formed on the color filters and microlenses made of inorganic film formed on the planarization film seems to be substantially planar. 
     Thus, when the interface between the inorganic film containing the microlens material and the organic film formed below the inorganic film is planar, the microlens is likely to be displaced due to the difference in thermal expansion coefficient between the materials, etc. 
     [1-2 Lower Profile] 
     Therefore, an image pickup element may include a non-planar layer which has a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on the light incident surface of the non-planar layer, and collects incident light. 
     Also, the microlens may include a plurality of layers. 
     Moreover, the layers of the microlens including the plurality of layers may have different refractive indices. 
     Also, the layers of the microlens including the plurality of layers may have different curved surface shapes. 
     Moreover, a portion of the layers of the microlens including the plurality of layers may be formed of an organic material. 
     Also, an anti-reflection film may be formed on a light incident surface of the microlens. 
     Moreover, the image pickup element may further include an adhesive material layer provided on a light incident surface of the microlens. 
     Also, the non-planar layer may have a filter. 
     Moreover, the filter may include filters with a plurality of colors having different thicknesses in a direction in which light passes. 
     Also, the filters having the different thicknesses may be arranged in a Bayer arrangement, corresponding to red, green, and blue pixels, and the green filters may be linked between pixels. 
     Moreover, the filter may be formed of an organic material. 
     Also, the non-planar layer may have an organic film which is formed on the filter and has a non-planar light incident surface. 
     Moreover, heights of projections and recesses of a light incident surface of the organic film may be lower than heights of projections and recesses of a light incident surface of the filter. 
     Also, the refractive index of the organic film may be between the refractive index of the filter and the refractive index of the microlens. 
     Moreover, the non-planar layer may have an inter-pixel light shield film. 
     Also, the non-planar layer may have projections and recesses on the light incident surface due to a difference in height between the filter and the inter-pixel light shield film. 
     Moreover, a chip size package structure may be formed. 
     Note that an image pickup device may include an image pickup element which captures an image of an object, and outputs the image of the object as an electrical signal, and an image processing unit which processes the image of the object obtained by the image pickup element. The image pickup element may include a non-planar layer which has a non-planar light incident surface in a light receiving region, and a microlens of an inorganic material which is provided on the light incident surface of the non-planar layer, and collects incident light. 
     Moreover, a manufacturing device may include a non-planar layer forming unit which forms a non-planar layer having a non-planar light incident surface in a light receiving region of an image pickup element, an inorganic film forming unit which forms an inorganic film on the light incident surface of the non-planar layer formed by the non-planar layer forming unit, a planarization film forming unit which forms a planarization film on a light incident surface of the inorganic film formed by the inorganic film forming unit, a resist forming unit which forms a resist on a light incident surface of the planarization film formed by the planarization film forming unit, a thermal reflow process unit which performs a thermal reflow process on the image pickup element on which the resist has been formed by the resist forming unit, and an etching process unit which performs etching on the image pickup element on which the thermal reflow process has been performed by the thermal reflow process unit. 
     Of course, a manufacturing method of the manufacturing device may be provided. 
     Thus, not only a smaller size, thinner thickness, and higher-density implementation of video equipment can be achieved, but also, when a wafer-level CSP is implemented as the structure of a solid-state image pickup device, even if an adhesive material is provided on the microlens, sensitivity characteristics which are greater than or equal to those of conventional packages in which air is present on a conventional microlens, can be obtained. 
     [1-3 Image Pickup Device] 
     A more specific example will be described.  FIG.  3    is a diagram showing an example main configuration of an image pickup device. The image pickup device  100  shown in  FIG.  3   , which may be included as an image pickup element in another device, converts light from an object into electricity, and outputs an image of the object as an image signal. 
     The image pickup device  100  shown in  FIG.  3    is formed to have the CSP structure. The image pickup device  100  includes a solid-state image pickup element which includes an image pickup region  121  which is formed on a semiconductor substrate  111  and on a surface of which a plurality of color filters  132 , a plurality of microlenses  133 , and a plurality of photodiodes  131 , etc., are provided, a peripheral circuit region  122  which is formed in an outer peripheral region of the image pickup region  121  of the semiconductor substrate  111 , and a plurality of electrode portions  123  formed in the peripheral circuit region  122 . 
     Also, a transparent substrate  143  made of, for example, optical glass etc. is formed on a main surface of the solid-state image pickup element above the microlenses  133  with an adhesive material A  141  and an adhesive agent B  142  made of a resin-based material being interposed therebetween. Moreover, on a back surface opposite to the main surface of the solid-state image pickup element, metal interconnects  125  connecting to the plurality of electrode portions  123  in the peripheral circuit region  122  are formed with through electrodes  124  penetrating through the semiconductor substrate in the thickness direction being interposed therebetween, and an insulating resin layer  126  which has openings which cover the metal interconnects  125  and expose a portion thereof is formed. External electrodes  127  made of, for example, a solder material are formed in the openings. Note that the solid-state image pickup element is electrically insulated from the through electrode  124  and the metal interconnect  125  by an insulating layer (not shown). 
     In the image pickup device  100 , the plurality of electrode portions  123  are electrically connected to the metal interconnects  125  through the through electrodes  124 , and also, are electrically connected to the external electrodes  127  through the metal interconnects  125 , and therefore, a received light signal can be extracted. 
     A of  FIG.  4    shows a plan view of the color filters  132  of red, green, and blue in a Bayer arrangement formed in the same light receiving region of the solid-state image pickup element. Also, B of  FIG.  4    shows a cross section (a side direction of the color filter  132 ) taken along the a-a′ direction in A of  FIG.  4   , and a cross section (a diagonal direction of the color filter  132 ) taken along the b-b′ direction. As shown in A of  FIG.  4    and B of  FIG.  4   , the green color filters are linked together at their four corners, and a red or blue color filter is formed in the openings of the green color filters. 
     Here, as shown in B of  FIG.  4   , the green color filters linked together at their four corners are formed to have a small thickness. Typically, a material for the color filter  132  used in the solid-state image pickup element is provided by adding a pigment or a dye, which are colorants, into photo-polymerization negative photosensitive resin. Although it is desirable that each color filter should be formed to have a pixel size of the solid-state image pickup element, the color filters  132  need to be formed to overlap in order to ensure the cohesiveness of the color filters  132  or prevent the occurrence of a gap due to misalignment of color filters of each color, etc. By forming the green color filters linked together at their four corners, the cohesiveness can be improved, and the occurrence of a gap can be reduced. 
     Here, if the four corners of the green color filter are formed to have a sufficient width, the pattern size increases, and therefore, the opening in which a red or blue color filter is to be formed is narrowed. For example, the green color filter enters a pixel in which a red or blue color filter should be formed, and the size of the red or blue color filter formed decreases, and as a result, the sensitivity with respect to blue or red decreases, or the color mixture of a green color component occurs, resulting in deterioration of characteristics of the solid-state image pickup element. 
     In order to cause the green color filter size to be as close to the pixel size as possible, and ensure the cohesiveness, it is necessary to increase the contact area, and in addition, form the color filters while avoiding a break in the four corner linkage portions of the green color filter, and eliminating a gap between each of the red, green, and blue color filters. It is necessary to form the color filters using an exposure mask whose mask pattern size is smaller than or equal to the limit of the resolution of the photosensitive resin during the formation of the color filters using photo-polymerization negative photosensitive resin. Typically, the color filters are formed using the exposure mask size which is 200 nm or less during the formation of the four corners. When the photo-polymerization negative photosensitive resin is formed using the exposure mask size which is smaller than or equal to the limit of the resolution, the photo-polymerization reaction is not sufficiently performed, so that that portion has a small film thickness (Δt). 
     As shown in A of  FIG.  5    and B of  FIG.  5   , microlenses made of inorganic film are formed above the red, green, and blue color filters  132  thus formed in a Bayer arrangement shown in A of  FIG.  4    and B of  FIG.  4   . 
     As described above, in the case of the conventional structure, as shown in A of  FIG.  1    a thickness from the bottom surface of the color filter to the bottom surface of the microlens is t 1 , and as shown in B of  FIG.  1    a thickness from the bottom surface of the color filter to the bottom surface of the microlens is t 2 . 
     In contrast to this, in the example of  FIG.  5   , although the color filters  132  have a level difference, a microlens including a single layer or a plurality of inorganic films is formed on the color filter without a planarization film (described below). Here, the thicknesses from the bottom surface of the color filter to the bottom surface of the microlens in the a-a′ direction and in the b-b′ direction are t 3  and t 4 . 
     Here, t 1  and t 2  are compared with t 3  and t 4 . In the example of  FIG.  1   , a bottom portion of the microlens is formed in the inorganic film. In the example of  FIG.  5   , although a bottom portion of the microlens  133  is similarly formed in the inorganic film, a planarization film is not formed, and therefore, the thicknesses have relationships t 1 &gt;t 3  and t 2 &gt;t 4 , and the layer thickness can be reduced. In other words, in the example of  FIG.  5   , the sensitivity characteristics of the solid-state image pickup element can be further improved. 
     Also, as shown by Δt in B of  FIG.  5   , the four corner portions of the green color filter can be formed to be thin, and therefore, the thickness can be proportionately reduced. Here, the bottom portion of the microlens in the b-b′ cross section is formed at a position where the green color filter is not exposed. This is because if the color filter  132  is exposed, the colorant contained in the color filter  132  is also etched, so that the inner wall of the etching processing chamber of the etching device is stained with the colorant. If the inner wall of the etching processing chamber is stained, the influence of dust, metal contamination in a metal-containing colorant, etc., causes a decrease in the yield of the image pickup device  100 . 
     Moreover, in the example of  FIG.  1   , by additionally applying etching to the state shown, the distance from the bottom portion of the color filter  132  to the bottom portion of the microlens  133  can be reduced. However, in this case, as shown in B of  FIG.  6   , the microlens is formed with the planarization film being exposed in the vicinity of the bottom portion of the microlens in the b-b′ cross-sectional direction. Therefore, the light collection power decreases in the bottom portion of the microlens in which the planarization film is exposed, due to the relationship of the refractive indices, leading to the risk of deterioration of the sensitivity characteristics of the solid-state image pickup element. 
     Note that, as shown in  FIG.  7   , a non-planar film  171  may be formed on the color filter  132 . In this case, an organic material or an inorganic material is selected to form the non-planar film  171  so that a level difference Δa in  FIG.  7    is reduced at the four corner portions of the green color filter. As the organic material, an acrylic-based resin, a styrene-based resin, an acrylic-styrene copolymer-based resin, etc. is used. The inorganic material is selected from silicon oxide film (SiO), SiON, SiN, etc. Here, by forming the non-planar film  171 , the planarity of the microlens  133  made of inorganic film formed on the non-planar film  171  as it is formed is improved (Δa&gt;Δb). Also, when, for the non-planar film, an acrylic-based resin is selected from the organic materials, SiON is formed on an upper surface of the non-planar film. This is because when the microlens  133  is made of SiN, the occurrence of creases due to the difference in stress between the films is prevented. In order to prevent the occurrence of creases, a styrene-based resin or an acrylic-styrene copolymer-based resin, which has a higher cured density of film than that of acrylic-based resins, is used. 
     As described above, the non-planar film  171  is formed on the color filter  132 , whereby the thickness from the lower portion of the color filter  132  to the lower portion of the microlens  133  is reduced. Even if the non-planar film  171  is exposed in the cross-section of the b-b′ direction, the area where the non-planar film  171  is exposed is small, and therefore, the light collection power of the microlens  133  is substantially equal to that of the structure shown in  FIG.  5    etc., leading to an improvement in the sensitivity of the solid-state image pickup element. Moreover, when the non-planar film  171  is made of SiON, then if the refractive index is set to be between those of the color filter and the microlens, the interfacial reflection can be reduced, leading to a further improvement in the sensitivity characteristics or a reduction in the flare characteristics. 
     For example, when the refractive index of the color filter  132  is about 1.51 to 1.75, and SiN, which has a refractive index of about 1.9, is used as a material for the microlens, SiON is formed to have an intermediate refractive index therebetween by suitably adjusting conditions for the film formation. 
     Note that the microlens  133  may include a plurality of layers. An example of the structure will be described using  FIG.  8   . Note that  FIG.  8    shows an a-a′ cross section of A of  FIG.  5   . A multi-layer microlens  181  shown in A of  FIG.  8    has a first microlens layer  181 - 1  and a second microlens layer  181 - 2 . Each layer may have any of three configurations shown in a table of  FIG.  9   . 
     Note that the refractive indices are assumed to have the following relative order of magnitude. 
     First Microlens≥Second Microlens 
     Also, a multi-layer microlens  182  shown in B of  FIG.  8    has a first microlens layer  182 - 1 , a second microlens layer  182 - 2 , and a third microlens layer  182 - 3 . Each layer may have any of four configurations shown in a table of  FIG.  10   . 
     Note that the refractive indices are assumed to have the following relative order of magnitude. 
     First Microlens Layer=Second Microlens Layer≥Third Microlens Layer 
     Here, in the configurations of 2 and 4 (the first microlens layer=the second microlens layer&gt;the third microlens layer), the second microlens layer mainly acts to reduce gaps in the first microlens layer, and the third microlens layer mainly functions as an anti-reflection film including a single layer. 
     A multi-layer microlens  183  shown in C of  FIG.  8    has a first microlens layer  183 - 1 , a second microlens layer  183 - 2 , a third microlens layer  183 - 3 , and a fourth microlens layer  183 - 4 . Each layer may have any of two configurations shown in a table of  FIG.  11   . 
     Note that the refractive indices are assumed to have the following relative order of magnitude. 
     Third Microlens Layer&gt;First Microlens Layer=Second Microlens Layer&gt;Fourth Microlens Layer 
     Here, the second microlens layer  183 - 2  mainly acts to reduce gaps in the first microlens layer  183 - 1 , and the third microlens layer  183 - 3  and the fourth microlens layer  183 - 4  mainly function as an anti-reflection film including two layers. 
     In  FIG.  11   , as a material of (d), zirconium oxide (ZnO, refractive index: about 2.4), titanium oxide (TiO, refractive index: about 2.52), etc. may be used, and as a material of (e), silicon oxide film (SiO, refractive index: about 1.45), silicon oxycarbide film (SiOC, refractive index: about 1.4), magnesium fluoride (MgF, refractive index: about 1.37), etc. may be used. 
     As described above, when the microlens  133  includes a plurality of layers, a portion of the layers may be a microlens layer made of an organic material. 
     For example, in the example of A of  FIG.  8   , an organic microlens may be formed as the first microlens layer  181 - 1 , and an inorganic microlens may be formed as the second microlens layer  181 - 2 . In this case, each microlens layer may have any of two configurations shown in a table of  FIG.  12   . 
     Also, the refractive indices are assumed to have the following relative order of magnitude. Here, the refractive index of the organic microlens can be adjusted according to the amount of fine metal oxide particles added. 
     First Microlens≥Second Microlens 
     Here, the second microlens layer  181 - 2  mainly acts to reduce gaps between lenses in the first microlens layer  181 - 1 . 
     For example, in the example of B of  FIG.  8   , an organic microlens may be formed as the first microlens layer  182 - 1 , and inorganic microlenses may be formed as the second microlens layer  181 - 2  and the third microlens layer  181 - 3 . In this case, each microlens layer may have any of four configurations shown in a table of  FIG.  12   . 
     Also, the refractive indices are assumed to have the following relative order of magnitude. Here, the refractive index of the organic microlens can be adjusted according to the amount of fine metal oxide particles added. 
     First Microlens Layer=Second Microlens Layer≥Third Microlens Layer 
     Here, in the configurations of 2 and 4 (the first microlens layer=the second microlens layer&gt;the third microlens layer), the second microlens layer  182 - 1  mainly acts to reduce gaps in the first microlens layer  182 - 1 , and the third microlens layer  181 - 3  mainly functions as an anti-reflection film. 
     For example, in the example of C of  FIG.  8   , an organic microlens may be formed as the first microlens layer  183 - 1 , and inorganic microlenses may be formed as the second microlens layer  183 - 2 , the third microlens layer  183 - 3 , and the fourth microlens layer  184 - 3 . In this case, each microlens layer may have any of two configurations shown in a table of  FIG.  14   . 
     Also, the refractive indices are assumed to have the following relative order of magnitude. Here, the refractive index of the organic microlens can be adjusted according to the amount of fine metal oxide particles added. 
     Third Microlens Layer&gt;First Microlens Layer=Second Microlens Layer&gt;Fourth Microlens Layer 
     Here, the second microlens layer  183 - 2  mainly acts to reduce gaps in the first microlens layer  183 - 1 , and the third microlens layer  183 - 3  and the fourth microlens  184 - 3  mainly function as an anti-reflection film including two layers. 
     In  FIG.  14   , as a material of (d), zirconium oxide (ZnO, refractive index: about 2.4), titanium oxide (TiO, refractive index: about 2.52), etc. may be used, and as a material of (e), silicon oxide film (SiO, refractive index: about 1.45), silicon oxycarbide film (SiOC, refractive index: about 1.4), magnesium fluoride (MgF, refractive index: about 1.37), etc. may be used. 
     2. Second Embodiment 
     [2-1 Manufacturing Device] 
     Next, a manufacturing device which manufactures the above-described image pickup device  100  (image pickup element) will be described. 
       FIG.  15    is a block diagram showing an example main configuration of a device for manufacturing the image pickup device  100 . A manufacturing device  200  shown in  FIG.  15    has a control unit  201  and a manufacture unit  202 . 
     The control unit  201 , which has, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), etc., controls each portion of the manufacture unit  202  to perform a control process involved in manufacture of the image pickup device  100  (image pickup element). For example, the CPU of the control unit  201  executes various processes according to programs stored in the ROM. Also, the CPU executes various processes according to programs loaded from a storage unit  213  to the RAM. The RAM also stores data which is required when the CPU executes various processes, etc., as appropriate. 
     The manufacture unit  202  is controlled by the control unit  201  to perform processes involved in manufacture of the image pickup device  100  (image pickup element). The manufacture unit  202  has a light receiving interconnect layer forming unit  231 , a filter forming unit  232 , a first inorganic film forming unit  233 , a planarization film forming unit  234 , a resist pattern forming unit  235 , a thermal reflow processing unit  236 , an etchback process unit  237 , a second inorganic film forming unit  238 , and an etchback process unit  239 . The light receiving interconnect layer forming unit  231  to the etchback process unit  239  are controlled by the control unit  201  to perform processes of steps of manufacturing the image pickup device  100  (image pickup element) as described below. 
     Note that, here, for the sake of convenience, only steps involved in the present technology will be described. Actually, in order to manufacture the image pickup device  100  (image pickup element), other steps than those performed by these processing units are required. Although the manufacture unit  202  has processing units for those steps, those steps will not be described herein in detail. 
     The manufacturing device  200  has an input unit  211 , an output unit  212 , a storage unit  213 , a communication unit  214 , and a drive  215 . 
     The input unit  211 , which includes a keyboard, a mouse, a touch panel, and an external input terminal, etc., receives input of, and supplies to the control unit  201 , a user&#39;s instruction or information from the outside. The output unit  212 , which includes a display, such as a CRT (Cathode Ray Tube) display or an LCD (Liquid Crystal Display) etc., a speaker, and an external output terminal, etc., outputs various items of information supplied from the control unit  201  as an image, audio, or an analog signal or digital data. 
     The storage unit  213 , which includes an SSD (Solid State Drive), such as a flash memory etc., or a hard disk, etc., stores information supplied from the control unit  201 , or reads and supplies stored information in accordance with a request from the control unit  201 . 
     The communication unit  214 , which includes, for example, an interface or a modem, etc. for a wired LAN (Local Area Network) or a wireless LAN, performs a communication process with respect to an external device through a network including the Internet. For example, the communication unit  214  transmits information supplied from the control unit  201  to the other end of communication, or supplies information received from the other end of communication to the control unit  201 . 
     The drive  215  is connected to the control unit  201  as required. And, a removable medium  221 , such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, etc., is loaded into the drive  215  as appropriate. And, a computer program read from the removable medium  221  through the drive  215  is installed in the storage unit  213  as required. 
     [2-2 Manufacturing Method] 
     An example flow of the manufacture process will be described with reference to a flowchart of  FIG.  16   . Note that reference is made to  FIG.  17    as appropriate.  FIG.  17    is a diagram for describing how each step of the manufacture process is performed. 
     When the manufacture process begins, in step S 101  the light receiving interconnect layer forming unit  231  is controlled by the control unit  201  to form a light receiving layer, an interconnect layer, etc. on an N-type semiconductor substrate supplied from the outside. 
     In step S 102 , the filter forming unit  232  forms filters (A of  FIG.  17   ). A of  FIG.  17    shows the color filters  132  in a Bayer arrangement which are formed corresponding to respective pixels of the image pickup device  100 . As a method for the color filter  132 , a photosensitive resin into which, for example, a pigment or a pigment as a colorant is added is formed using photolithography. As the color filters  132 , color materials, such as, for example, red, green, blue, etc., are formed. In this case, there is a level difference between adjacent color filters  132 . 
     In step S 103 , the first inorganic film forming unit  233  forms a first inorganic film (B of  FIG.  17   ). B of  FIG.  17    shows the first microlens layer  181 - 1  which is formed using P-CVD. In this case, the film formation is performed under the following conditions: SiH4, NH3, N20, and N2 are used as film formation gas if the first microlens layer  181 - 1  is SiON, or SiH4, NH3, and N2 are used as film formation gas if the first microlens layer  181 - 1  is SiN; and the film is formed by P-CVD at a temperature of about 200° C., where the pressure etc. is adjusted as appropriate. 
     At this time, as to the film formation technique using P-CVD, for the film formation conditions, the mean free path during the film formation is adjusted, taking the level difference of the color filters  132  into consideration, so that the level difference is reduced. 
     Silicon nitride (SiN) film
         gas: SiH4, NH3, N2   temperature: about 200° C.       

     Silicon oxynitride (SiON) film
         gas: SiH4, NH3, N2O, N2   temperature: about 200° C.       

     pressure: 2 mTorr to 10 Torr 
     Here, the mean free path becomes gradually higher toward 2 mTorr and lower toward 10 Torr. Therefore, as to the planarity (Δh) after the film formation of the first microlens layer in terms of the film thickness ratio of Tf and Tg shown in  FIG.  18   , Tg/Tf decreases when the firm formation is performed under pressure conditions which provide a higher mean free path. As a result, the planarization film of resin can be formed to have a thin thickness as it is formed, and the first microlens can be satisfactorily formed because of a slight difference in etching selection ratio between the first microlens layer  181 - 1  and the planarization film of resin during dry etching in the formation of the first microlens. 
     In step S 104 , the planarization film forming unit  234  forms a planarization film (C of  FIG.  17   ). As shown in C of  FIG.  17   , a middle film  401  which will be positioned between the first microlens layer  181 - 1  and a photoresist pattern which will be next formed, is formed on the first microlens layer  181 - 1 . Here, the middle film  401  is formed of a material which has a larger thermal expansion coefficient than that of the photoresist. 
     A photoresist pattern described below is formed on and made contact with the middle film  401  having a larger thermal expansion coefficient than that of the resist, and thereafter, the resist is shaped into a lens by thermal reflow. As a result, the middle film  401  having a larger thermal expansion coefficient than that of the photoresist can reduce a force which is caused by the photoresist spreading during the thermal reflow, thereby reducing the amount of sliding of the photoresist pattern formed in contact with the middle film  401 . Therefore, even if the length of the gap of the photoresist pattern is narrowed, adjacent resists are not in contact with each other, and therefore, the occurrence of a pattern collapse due to fusion can be prevented. 
     At this time, a film thickness  401  of the middle film is preferably 150 nm or more in a thinnest region. If the film thickness is smaller than or equal to this value, the effect which is obtained using the difference in thermal expansion coefficient cannot be obtained, and the controllability of the lens shape is likely to deteriorate. 
     In step S 105 , the resist pattern forming unit  235  forms a resist pattern (D of  FIG.  17   ). D of  FIG.  17    shows a state in which a photoresist pattern  402  is formed on the first lens layer, corresponding to each pixel of the image pickup device  100 . As a positive photosensitive resin, a material based on a novolac-based resin, a styrene-based resin, or a copolymer-based resin of these resins, is used. 
     Also, the pattern formation is performed using spin coating, prebake, i-line exposure, post-exposure bake, or a development process. 
     In step S 106 , the thermal reflow processing unit  236  performs a thermal reflow process (E of  FIG.  17   ). As shown E of  FIG.  17   , the photoresist pattern  402  is baked by a thermal treatment at a temperature which is higher than or equal to the thermal softening point. In this bake process, a lens shape is obtained as shown in E of  FIG.  17   . 
     In step S 107 , the etchback process unit  237  performs an etching process (F of  FIG.  17   ). F of  FIG.  17    shows a state in which a photoresist  402  having a lens shape is used as a mask to transfer the shape to the first microlens layer  181 - 1  by etching. As to the etching process at this time, a device, such as an ICP (Inductively Coupled Plasma) device, a CCP (Capacitively Coupled Plasma) device, a TCP (Transformer Coupled Plasma) device, a magnetron RIE (Reactive Ion Etching) device, an ECR (Electron Cyclotron Resonance) device, etc., is used as a plasma generating device, and a fluorocarbon gas-based gas, such as CF4, C4F8, etc., is used as a major component to perform the etching process while adjusting the temperature, the pressure, etc. as appropriate. At this time, as shown in F of  FIG.  17    or G of  FIG.  17   , there is a gap between adjacent first microlens layers  181 - 1 , and a gap shown in the b-b′ cross-sectional view is larger. 
     In step S 111 , the second inorganic film forming unit  238  forms a second inorganic film (G of  FIG.  17   ). G of  FIG.  17    shows a state in which a film of SiN is formed as the second microlens layer  181 - 2 . As a film formation gas at this time, SiH4, NH3, and N2 are used, and the film is formed by P-CVD at a temperature of about 200° C., where the pressure etc. is adjusted as appropriate. At this time, as shown in the a-a′ b-b′ cross-sectional views, the film is formed so that a gap between adjacent second microlens layers  181 - 2  is eliminated. 
     As to this film formation technique using P-CVD, the curvature of the microlens  133  can be adjusted by adjusting the mean free path when a SiN or SiON film is formed as the second microlens layer  181 - 2 . The specific film formation conditions are as follows. 
     Silicon nitride (SiN) film
         gas: SiH4, NH3, N2   temperature: about 200° C.       

     Silicon oxynitride (SiON) film
         gas: SiH4, NH3, N2O, N2   temperature: about 200° C.       

     pressure: 2 mTorr to 10 Torr 
     The mean free path becomes gradually higher toward 2 mTorr and lower toward 10 Torr. 
     By adjusting the mean free path as described above, the curvature of the second microlens layer  181 - 2  can be adjusted with respect to the first microlens layer  181 - 1  having the same shape. 
     For example, as shown in A of  FIG.  19   , when the film is formed under conditions that the mean free path is relatively large, Tb/Tt decreases and the curvature increases in the figure. As shown B of  FIG.  19   , when the mean free path is decreased, Tb/Tt increases and the curvature decreases. By adjusting the microlens curvature, not only microlenses which are applicable to CSP, but also microlenses which are applicable to various solid-state image pickup elements, can be formed. 
     Moreover, even when the first lens layer  181 - 1  has a non-curved surface shape as shown in  FIG.  20   , the second microlens layer  181 - 2  which is corrected to have a shape similar to a curved surface can be formed by adjusting the film formation conditions. 
     In step S 112 , the etchback process unit  239  performs an etching process (H of  FIG.  11   ). 
     Etchback is performed on the entire second microlens layer  181 - 2  which has been formed so that a gap between lens layers is eliminated, in order to provide a low profile in a cross-sectional direction of the device. As to the etching process at this time, a device, such as an ICP (Inductively Coupled Plasma) device, a CCP (Capacitively Coupled Plasma) device, a TCP (Transformer Coupled Plasma) device, a magnetron RIE (Reactive Ion Etching) device, an ECR (Electron Cyclotron Resonance) device, etc., is used as a plasma generating device, and a fluorocarbon gas-based gas, such as CF4, C4F8, etc., is used as a major component, to perform the etching process while adjusting the temperature, the pressure, etc. as appropriate. Thus, by performing etchback on the front surface, the bottom position of the microlens is lowered, whereby the sensitivity characteristics of the solid-state image pickup element are improved. 
     When the process of step S 109  ends, the manufacture process ends. 
     By performing the processes as described above, an image pickup element which is manufactured so that deterioration of the sensitivity characteristics is reduced can be obtained. 
     As described above, a manufacturing method in which the inorganic microlenses  181  are formed as the first microlens layer  181 - 1  and the second microlens layer  181 - 2  is shown. Alternatively, the first microlens layer  181 - 1  may be an organic microlens to which fine metal oxide particles are added. 
     As to a manufacturing method in which the first microlens layer  181 - 1  is an organic microlens, in the step of C of  FIG.  17   , for example, an organic microlens material may be used which employs an epoxy-based resin in which titanium oxide is added to fine metal particles. This organic microlens is formed by spin coating followed by a thermal treatment at about 150 to 200° C. In addition, the manufacturing method is optimized as appropriate, as described above. 
     Also, as the microlens structure of the multi-layer microlens layer  182 , main film formation conditions which are used when a silicon oxide (SiO) film is used are as follows. 
     Silicon oxide (SiO) film
         gas: SiH4, N2O   temperature: about 200° C.   pressure: 2 mTorr to 10 Torr       

     Also, as a film formation method for the third microlens layer  183 - 3  and the fourth microlens of the multi-layer microlens layer  183  of  FIG.  8   , vacuum vapor deposition, sputtering, ion vapor deposition, ion beam, mist CVD (Chemical Vapor Deposition), etc. is used. 
     [2-3 Supplements] 
       FIG.  21    shows a state in which the adhesive material A  141  shown in  FIG.  3    is formed on the microlens. As a material for the adhesive material A  141 , an acrylic-based resin (n=1.5) or a siloxane-based resin (n=1.42 to 1.45) may be used, or in order to reduce the refractive index, fluorine may be introduced to a side chain of the resin (n=1.4 to 1.44), or hollow silica particles may be added (n=1.3 to 1.39). Also, in the figure, a SiON film having an intermediate refractive index between those of the microlens and the adhesive material is formed, whereby the interface reflection can be reduced. The reduction of the interface reflection can lead to an improvement in the sensitivity characteristics of the solid-state image pickup element, or a reduction in flare, etc. 
     Also, the adhesive material A  141  of  FIG.  21    may also serve as the adhesive material B  142  of  FIG.  3    (not shown). When the adhesive material A  141  also serves as the adhesive material B  142 , the number of interfaces having different refractive indices is reduced, and therefore, the reflection loss of incident light decreases. As shown in  FIG.  22   , the decrease of the reflection loss can lead to an improvement in the sensitivity characteristics of the solid-state image pickup element, or a reduction in flare, etc. 
     Note that the present technology is not limited to chip size packages (CSPs). For example, a planarization film which has a lower refractive index than that of the microlens may be formed on the microlens, and a solid-state image pickup device may be packaged in a hollow form. 
     Also, the arrangement of the color filters  132  in the present technology is not limited to a prime color Bayer arrangement. For example, a filter having any color and arrangement, such as a complementary color filter, a white (transparent) color filter, a black color filter, etc., can be used. 
     Also, a light shield film may be provided between pixels. For example, as shown in A of  FIG.  23   , an inter-pixel light shield film  452  may be provided between pixels, and a filter of each color of buried color filters  441  may be buried in a light receiving portion of each unit pixel  451 . In this case, as shown in B of  FIG.  23    or C of  FIG.  23   , projections and recesses of the light incident surface are formed by the filters and the inter-pixel light shield film  452 . 
     Also, as shown in A of  FIG.  24   , a buried color filter  461  may be provided on the inter-pixel light shield film. In this case, as shown in A of  FIG.  24   , the inter-pixel light shield film is not exposed on the light incident surface. 
     As shown in B of  FIG.  24    and C of  FIG.  24   , an inter-pixel light shield film  472  is formed below the buried color filter  461 . Therefore, projections and recesses of the light incident surface are formed by the buried color filter  461 . 
     In any of the cases, similar to the foregoing, the microlens  133  can be formed. 
     3. Third Embodiment 
     [3-1 Manufacturing Device] 
     Note that the method for manufacturing the image pickup device is not limited to the examples described above. For example, instead of forming the non-planar film  171  which has been described with reference to  FIG.  7    by coating, the non-planar layer may be formed by etching. 
       FIG.  25    is a block diagram showing an example main configuration of a manufacturing device in that case. A manufacturing device  500  shown in  FIG.  25   , which is generally similar to the manufacturing device  200 , manufactures the image pickup device  100 . The manufacturing device  500  has a control unit  501  and a manufacture unit  502 , as with the manufacturing device  200 . 
     The control unit  501 , which is a processing unit which is similar to the control unit  201 , has a CPU, a ROM, and a RAM, etc., and controls each portion of the manufacture unit  502  to perform control processes involved in manufacture of the image pickup device  100  (image pickup element). 
     The manufacture unit  502 , which is a processing unit similar to the manufacture unit  202 , is controlled by the control unit  501  to perform processes involved in manufacture of the image pickup device  100  (image pickup element). 
     The manufacture unit  502  has a light receiving interconnect layer forming unit  531 , a filter forming unit  532 , a planarization film forming unit  533 , a first inorganic film forming unit  534 , a resist pattern forming unit  535 , a thermal reflow processing unit  536 , an etchback process unit  537 , an etchback process unit  538 , a second inorganic film forming unit  539 , and an etchback process unit  540 . The light receiving interconnect layer forming unit  531  to the etchback process unit  540  are controlled by the control unit  501  to perform processes of steps of manufacturing the image pickup device  100  (image pickup element) as described below. 
     Note that, here, for the sake of convenience, only steps involved in the present technology will be described. Actually, in order to manufacture the image pickup device  100  (image pickup element), other steps than those performed by these processing units are required. Although the manufacture unit  502  has processing units for those steps, those steps will not be described herein in detail. 
     The manufacturing device  500  has an input unit  511 , an output unit  512 , a storage unit  513 , a communication unit  514 , and a drive  515 . The input unit  511  to the drive  515  are processing units similar to the input unit  211  to the drive  215 , respectively, have similar configurations, and perform similar processes. 
     A removable medium  521  similar to the removable medium  221  is loaded into the drive  515  as appropriate. A computer program read from the removable medium  521  through the drive  515  is installed in the storage unit  513  as required. 
     [3-2 Manufacturing Method] 
     An example flow of the manufacture process will be described with reference to a flowchart of  FIG.  26   . Note that reference is made to  FIG.  27    as appropriate.  FIG.  27    is a diagram for describing how each step of the manufacture process is performed. 
     When the manufacture process begins, in step S 501  the light receiving interconnect layer forming unit  531  is controlled by the control unit  201  to form a light receiving layer, an interconnect layer, etc. on an N-type semiconductor substrate supplied from the outside. 
     In step S 502 , the filter forming unit  532  forms filters (A of  FIG.  27   ). A of  FIG.  27    shows color filters  132 . 
     In step S 503 , the planarization film forming unit  234  forms a planarization film  551  on the color filters  132  (B of  FIG.  27   ). The planarization film  551  is formed of a material similar to that for the non-planar film  171 , and a surface of the planarization film  551  is finally caused not to be planar, as with the non-planar film  171 . Specifically, on the color filters  132 , a non-planar layer having a non-planar surface, which is the planarization film  551  which has been processed, is formed. Note that, during film formation, the non-planar layer is formed as the planarization film  551  as described above. 
     In step S 504 , the first inorganic film forming unit  534  forms the first microlens layer  181 - 1  as a first inorganic film on the planarization film  551  (C of  FIG.  27   ). The film formation conditions are similar to those of the second embodiment. Note that, similar to the second embodiment, the middle film  401  may be formed on the first inorganic film (the first microlens layer  181 - 1 ). 
     In step S 505 , the resist pattern forming unit  535  forms a resist pattern  402  on the first inorganic film (the first microlens layer  181 - 1 ) (D of  FIG.  27   ). 
     In step S 506 , the thermal reflow processing unit  536  performs a thermal reflow process (E of  FIG.  27   ). As shown in E of  FIG.  27   , the photoresist pattern  402  is baked by a thermal treatment at a temperature which is higher than or equal to the thermal softening point. In this bake process, a lens shape is obtained as shown in E of  FIG.  27   . 
     In step S 507 , the etchback process unit  537  performs an etching process (F of  FIG.  27   ). F of  FIG.  27    shows a state in which the photoresist  402  having a lens shape is used as a mask to transfer the shape to the first microlens layer  181 - 1  by etching. The etching process method at this time is similar to that of the second embodiment described above with reference to F of  FIG.  17   . 
     As shown by dotted line circles c and d in F of  FIG.  27   , the planarization film  551  is exposed by removing the first inorganic film (the first microlens layer  181 - 1 ) (e.g., SiN) at a peripheral portion of the microlens by etching. Here, by detecting C—O emission spectrum during the etching, the controllability of a position where the microlens is formed, in the height direction, can be further improved. 
     In step S 508 , the etchback process unit  538  performs an additional etching process (G of  FIG.  27   ). Specifically, the etchback process unit  538  continues the dry etching performed in step S 507 . As a result, as shown by dotted line circles e or f in G of  FIG.  27   , level differences (projections and recesses) are formed on a surface of the planarization film  551  on the color filters (CF)  132  at the peripheral portion of the micro T lens. Specifically, projections and recesses are formed on the surface of the planarization film  551  to form a non-planar film  552 . 
     At that time, the etchback process unit  538  may control the process time of the etching process based on a time from reference time which is time when the etchback process unit  537  detects the C—O spectrum as described above. Thus, the etchback process unit  538  can more accurately control a depth of the level differences (projections and recesses formed). 
     Note that, in this etching process, the etchback process unit  538  controls the process time so that projections and recesses are formed to an extent that the color filters  132  are not exposed. 
     In step S 509 , the second inorganic film forming unit  539  forms the second microlens layer  181 - 2  as a second inorganic film on the first inorganic film (the first microlens layer  181 - 1 ) etc. which has been dry-etched (H of  FIG.  27   ). H of  FIG.  27    shows a state in which a film of SiN is formed as the second microlens layer  181 - 2 . The film formation conditions are similar to those of the second embodiment. 
     At this time, the second inorganic film (the second microlens layer  181 - 2 ) is formed so that a gap between adjacent second microlens layers  181 - 2  is eliminated as shown in the a-a′ b-b′ cross-sectional views. As shown in the a-a′ b-b′ cross-sectional views, the second microlens layer  181 - 2  is formed to an extent that a gap between adjacent second microlens layers  181 - 2  is substantially eliminated. Note that a position of an upper portion of the microlens in which the second inorganic film (the second microlens layer  181 - 2 ) is formed is represented by t 0 . 
     In step S 510 , the etchback process unit  540  perform an etching process to an extent that the first inorganic film (the first microlens layer  181 - 1 ) and the non-planar film  552  are covered by the second inorganic film (the second microlens layer  181 - 2 ), i.e., are not exposed (J of  FIG.  27   ). 
     This process causes the above position t 0  to be t 1 , and therefore, a low profile is achieved in a cross-sectional direction. When the low profile is achieved, characteristics of the image pickup device  100  (image pickup element) are improved. 
     When the process of step S 510  ends, the manufacture process ends. 
     [3-3 Image Pickup Element] 
     By the above manufacture process, a microlens is formed on the non-planar layer (the non-planar film  552 ) as shown in, for example,  FIG.  28   . 
     In this case, as shown in a dotted line circle  553  of A of  FIG.  28    or in a dotted line circle  554  of B of  FIG.  28   , depressions (recesses) are formed on a surface of the non-planar film  552  in both the a-a′ direction and the b-b′ direction, and the microlens is formed with a portion (end portion) thereof being buried in the depression (recess). In other words, the microlens is formed in the depression (recess) on the surface of the non-planar film  552 . The microlens of  FIG.  28    includes a plurality of layers, i.e., the first microlens layer  181 - 1  and the second microlens layer  181 - 2 . In the case of such a multi-layer microlens, a portion (end portion) of at least one of the layers is formed in the depression. 
     With such a configuration, the displacement of the microlens which is caused by a thermal treatment after the formation of the microlens, etc., can be reduced. 
     [3-4 Manufacturing Device] 
     Although, as described above, the depression (recess) on the surface of the non-planar film is formed in a peripheral portion of the microlens (pixel), it is not necessary that the depression (recess) should be formed in the entire peripheral portion, and the depression (recess) may be formed in a portion of the peripheral portion. For example, the depression (recess) may be formed only in a diagonal direction (the b-b′ direction) of the pixel (i.e., only corners). 
       FIG.  29    is a block diagram showing an example main configuration of the manufacturing device in that case. As shown in  FIG.  29   , in this case, the manufacture unit  502  of the manufacturing device  500  has a second inorganic film forming unit  561 , an etchback process unit  562 , and an anti-reflection film processing unit  563  instead of the etchback process unit  538  to the etchback process unit  540 . These processing units are also controlled by the control unit  501  to perform processes of steps of manufacturing the image pickup device  100  (image pickup element) as described below. 
     [3-5 Manufacturing Method] 
     An example flow of the manufacture process will be described with reference to a flowchart of  FIG.  30   . Note that reference is made to  FIG.  31    as appropriate.  FIG.  31    is a diagram for describing how each step of the manufacture process is performed. 
     When the manufacture process begins, processes of step S 531  to step S 537  are executed in a manner similar to that of the processes of step S 501  to step S 507  of  FIG.  26   . 
     Note that the etchback process of step S 537  ends when a C—O emission spectrum is detected. And, in step S 538 , the second inorganic film forming unit  561  forms a second inorganic film (the second microlens layer  181 - 2 ) to an extent that a gap of the microlens in the cross-sectional view in the a-a′ direction and the b-b′ direction is substantially eliminated (A of  FIG.  31   ). By performing the film formation until a gap of the microlens is substantially eliminated, a difference in height between the a-a′ direction and the b-b′ direction occurs in the pixel peripheral portion. For example, as shown in A of  FIG.  31   , a position of an upper portion of the pixel peripheral portion in the a-a′ direction is represented by t 2 , and a position of the upper portion of the pixel peripheral portion in the b-b′ direction is represented by t 3 . In this case, the second inorganic film is formed so that the position t 3  of the upper portion of the four corners of the pixel (the pixel peripheral portion in the b-b′ direction) is lower than the position t 2  of the upper portion of the pixel peripheral portion in the a-a′ direction. 
     In step S 539 , the etchback process unit  562  performs an etchback process using this height difference to form local depressions (recesses) on the surface of the planarization film  551  (B of  FIG.  31   ). As described above, the underlying organic film is reached earlier at sites corresponding to the four corners of the microlens formed at a low position with respect to the cross-sectional direction. At this time, the etching process is carried out so that level differences are formed in the organic film (the planarization film  551 ) at at least the sites corresponding to the four corners of the microlens. 
     In step S 539 , the anti-reflection film forming unit  563  forms an anti-reflection film  571  which is an inorganic film on a surface of each layer exposed by the etching process (dry etching) (C of  FIG.  31   ). This inorganic film is selected from transparent materials which have a refractive index which reduces the surface reflection of the microlens made of, for example, SiN, and has an intermediate refractive index between those of the microlens material and a transparent film formed in an upper portion of the microlens material. Thus, this inorganic film has the function of resisting the displacement caused by a thermal treatment in addition to the function of preventing the surface reflection of the microlens. 
     When the process of step S 539  ends, the manufacture process ends. 
     [3-6 Image Pickup Element] 
     By the above manufacture process, a microlens shown in  FIG.  32    is formed on the non-planar layer (the non-planar film  552 ), for example. 
     In this case, as shown in A of  FIG.  32   , a depression is not formed on the surface of the planarization film  551  in the a-a direction, i.e., the planarization film  551  is not changed. In contrast to this, in the b-b′ direction, as shown B of  FIG.  3   , depressions (recesses) are formed on the surface of the planarization film  551  (a dotted line circle  572 ). Thus, the non-planar film  552  is formed. And, the anti-reflection film  571  is formed in the depressions (recesses). 
     Therefore, similar to the case of  FIG.  28   , the displacement of the microlens which occurs due to a thermal treatment after the formation of the microlens can be reduced. Also, as shown in  FIG.  32   , also in this case, a low profile is achieved in a cross-sectional direction. When a low profile is achieved, characteristics of the image pickup device  100  (image pickup element) are improved. 
     Note that, in a structure in a cross-sectional view of the image pickup element of each of the above examples, the microlens of inorganic film is formed without exposing organic films, such as the color filters etc., whereby damage on organic films, such as the color filters etc., which is caused by external moisture can be reduced. As a result, deterioration of spectral characteristics etc. of the image pickup element can be reduced. 
     [3-7 Image Pickup Element] 
       FIG.  33    is a diagram showing an example image pickup element. As shown in  FIG.  33   , typically, in a pixel region of the image pickup element  590  in which pixels are formed, in addition to an image capture region  591  (also referred to as an effective pixel region) which actually generates a captured image, an outer peripheral region  592  is also formed around the image capture region  591 . This outer peripheral region  592  is, for example, used as a margin for reducing variations in process, or alternatively, a light shield film which is used as an OPB region is formed in the outer peripheral region  592 . The pixels of the outer peripheral region  592  have a configuration generally similar to those of the image capture region  591 . 
     In the pixel region of the image pickup element  590  thus configured, not only the pixels of the image capture region  591 , but also the pixels of the outer peripheral region  592 , may be configured so that the microlens of an inorganic material is formed on the non-planar layer as described above. Thus, the microlens is formed on the non-planar layer over a wider range, and therefore, the displacement of the microlens which occurs due to a thermal treatment etc. can be further reduced. 
     Also, in that case, the pixels of the image capture region  591  and the pixels of the outer peripheral region  592  can be formed together by a common process. As a result, the increase in time and effort of the manufacture process can be reduced, and the increase in cost can be reduced. 
     Note that, the above configuration in which the microlens of an inorganic material is provided on the non-planar layer may, for example, be provided only in a portion of the pixels, such as one row per several rows or one pixel per several pixels. The proportion may or may not be uniform over the entire pixel region. For example, only pixels in the outer peripheral region may have such a configuration. 
     4. Fourth Embodiment 
     [Image Pickup Device] 
       FIG.  34    is a block diagram showing an example main configuration of an image pickup device. The image pickup device  600  shown in  FIG.  34    is a device which captures an image of an object, and outputs the image of the object as an electrical signal. 
     As shown in  FIG.  34   , the image pickup device  600  has an optical unit  611 , a CMOS sensor  612 , an A/D converter  613 , an operation unit  614 , a control unit  615 , an image processing unit  616 , a display unit  617 , a codec processing unit  618 , and a recording unit  619 . 
     The optical unit  611  includes a lens which adjusts a focal point to an object and collects light from an in-focus position, a diaphragm which adjusts exposure, and a shutter which controls timing of image capture, etc. The optical unit  611  allows light (incident light) from an object to pass therethrough, and supplies the light to the CMOS sensor  612 . 
     The CMOS sensor  612  perform photoelectric conversion on incident light, and supplies a signal (pixel signal) of each pixel to the A/D converter  613 . 
     The A/D converter  613  converts the pixel signal supplied from the CMOS sensor  612  with predetermined timing into digital data (image data), and supplies the digital data sequentially to the image processing unit  616  with predetermined timing. 
     The operation unit  614 , which includes, for example, a jog dial (trademark), a key, a button, or a touch panel etc., receives an operational input by the user, and supplies a signal corresponding to the operational input to the control unit  615 . 
     The control unit  615  controls drive of the optical unit  611 , the CMOS sensor  612 , the A/D converter  613 , the image processing unit  616 , the display unit  617 , the codec processing unit  618 , and the recording unit  619  based on a signal corresponding to an operational input of the user input from the operation unit  614 , to cause each unit to perform a process involved in image capture. 
     The image processing unit  616  performs various image processes, such as, for example, color mixture correction, black level correction, white balance adjustment, demosaicing, matrix processing, gamma correction, and YC conversion, etc., on image data supplied from the A/D converter  613 . The image processing unit  616  supplies the image data on which image processing has been performed, to the display unit  617  and the codec processing unit  618 . 
     The display unit  617 , which is configured as, for example, a liquid crystal display etc., displays an image of an object based on the image data supplied from the image processing unit  616 . 
     The codec processing unit  618  performs a predetermined encoding process on the image data supplied from the image processing unit  616 , and supplies the resultant encoded data to the recording unit  619 . 
     The recording unit  619  records the encoded data from the codec processing unit  618 . The encoded data recorded in the recording unit  619  is read out into and decoded by the image processing unit  616  as required. The image data obtained by the decoding process is supplied to the display unit  617 , which displays the corresponding image. 
     The present technology described above is applied to the CMOS sensor  612  of the above image pickup device  600 . Specifically, the above image pickup device  100  is used in the CMOS sensor  612 . Therefore, the CMOS sensor  612  can reduce deterioration of the sensitivity characteristics. Therefore, the image pickup device  600  can capture an image of an object, thereby obtaining an image having higher image quality. 
     Note that the image pickup device to which the present technology is applied is not limited to the above configuration, and may have other configurations. In addition to, for example, a digital still camera and a camcorder, the image quality device may be an information processing device having the function of capturing an image, such as a mobile telephone, a smartphone, a tablet device, a personal computer, etc. Also, the image pickup device may be a camera module which is attached to another information processing device in use (or loaded as an embedded device). 
     5. Fifth Embodiment 
     &lt;Computer&gt; 
     The above mentioned series of processes can, for example, be executed by hardware, or can be executed by software. In the case where the series of processes is executed by software, a program configuring this software is installed in a computer via a network of from a recording medium. 
     The storage medium includes, as shown in  FIG.  15   ,  FIG.  25   , and  FIG.  29   , for example, the removable medium  221  and the removable medium  521  storing the program, which is distributed for delivering the program to a user independently from the apparatus. The removable medium  221  and the removable medium  521  include a magnetic disk (including flexible disk) and an optical disk (including CD-ROM and DVD), and further includes a magneto optical disk (including MD (Mini Disc)), a semiconductor memory and the like. Alternatively, besides the removable medium  221  or the removable medium  521 , the above-described storage medium may include ROM that stores the program, which is distributed to the user in the form of being preliminarily installed in the apparatus, and a hard disk included in the storage part  213 . 
     The expression “computer” includes a computer in which dedicated hardware is incorporated and a general-purpose personal computer or the like that is capable of executing various functions when various programs are installed. 
       FIG.  35    is a block diagram showing an example configuration of the hardware of a computer that executes the series of processes described earlier according to a program. 
     In the computer  800  shown in  FIG.  35   , a central processing unit (CPU)  801 , a read only memory (ROM)  802  and a random access memory (RAM)  803  are mutually connected by a bus  804 . 
     An input/output interface  810  is also connected to the bus  804 . An input unit  811 , an output unit  812 , a storage unit  831 , a communication unit  814 , and a drive  815  are connected to the input/output interface  810 . 
     The input unit  811  is configured from a keyboard, a mouse, a microphone, a touch panel, an input terminal or the like. The output unit  812  is configured from a display, a speaker, an output terminal or the like. The storage unit  813  is configured from a hard disk, a RAM disk, a non-volatile memory or the like. The communication unit  814  is configured from a network interface or the like. The drive  815  drives a removable medium  821  such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory or the like. 
     In the computer  800  configured as described above, the CPU  801  loads a program that is stored, for example, in the storage unit  813  onto the RAM  803  via the input/output interface  810  and the bus  804 , and execute the program. Thus, the above-described series of processing is performed. The RAM  803  stores data in a suitable manner, which is necessary for the CPU  801  to execute various processing. 
     Programs to be executed by the computer (the CPU  801 ) are applied being recorded in the removable medium  821  which is a packaged medium or the like. Also, programs may be provided via a wired or wireless transmission medium, such as a local area network, the Internet or digital satellite broadcasting. 
     In the computer, by loading the removable medium  821  into the drive  815 , the program can be installed into the storage unit  831  via the input/output interface  810 . It is also possible to receive the program from a wired or wireless transfer medium using the communication unit  814  and install the program into the storage unit  813 . As another alternative, the program can be installed in advance into the ROM  802  or the storage unit  813 . 
     Note that the program executed by the computer may be a program in which processes are carried out in a time series in the order described in this specification or may be a program in which processes are carried out in parallel or at necessary timing, such as when the processes are called. 
     Note that, in this specification, steps that write the program to be recorded in the recording medium do not necessarily have to be performed in time series in line with the order of the steps, and instead may include processing that is performed in parallel or individually. 
     Further, in the present disclosure, a system has the meaning of a set of a plurality of configured elements (such as an apparatus or a module (part)), and does not take into account whether or not all the configured elements are in the same casing. Therefore, the system may be either a plurality of apparatuses, stored in separate casings and connected through a network, or a plurality of modules within a single casing. 
     Further, an element described as a single device (or processing unit) above may be divided to be configured as a plurality of devices (or processing units). On the contrary, elements described as a plurality of devices (or processing units) above may be configured collectively as a single device (or processing unit). Further, an element other than those described above may be added to each device (or processing unit). Furthermore, a part of an element of a given device (or processing unit) may be included in an element of another device (or another processing unit) as long as the configuration or operation of the system as a whole is substantially the same. 
     It should be noted that the program executed by a computer may be a program that is processed in time series according to the sequence described in this specification or a program that is processed in parallel or at necessary timing such as upon calling. 
     For example, the present disclosure can adopt a configuration of cloud computing which processes by allocating and connecting one function by a plurality of apparatuses through a network. 
     Further, each step described by the above mentioned flow charts can be executed by one apparatus or by allocating a plurality of apparatuses. 
     In addition, in the case where a plurality of processes is included in one step, the plurality of processes included in this one step can be executed by one apparatus or by allocating a plurality of apparatuses. 
     Additionally, the present technology may also be configured as below. 
     (1) 
     An image pickup element including: 
     a non-planar layer having a non-planar light incident surface in a light receiving region; and 
     a microlens of an inorganic material which is provided on a side of the light incident surface of the non-planar layer, and collects incident light. 
     (2) 
     The image pickup element according to (1), wherein 
     the microlens includes a plurality of layers. 
     (3) 
     The image pickup element according to (2), wherein 
     the layers of the microlens including the plurality of layers have different refractive indices. 
     (4) 
     The image pickup element according to (2) or (3), wherein 
     the layers of the microlens including the plurality of layers have different curved surface shapes. 
     (5) 
     The image pickup element according to any one of (2) to (4), wherein 
     at least a portion of the layers of the microlens including the plurality of layers is formed in a recess portion of the non-planar layer. 
     (6) 
     The image pickup element according to any one of (1) to (5), wherein 
     an anti-reflection film is formed over a light incident surface of the microlens. 
     (7) 
     The image pickup element according to any one of (1) to (6), further including: 
     an adhesive material layer provided on a side of a light incident surface of the microlens. 
     (8) 
     The image pickup element according to any one of (1) to (7), wherein 
     the non-planar layer has a filter. 
     (9) 
     The image pickup element according to (8), wherein 
     the filter includes filters with a plurality of colors having different thicknesses in a direction in which light passes. 
     (10) 
     The image pickup element according to (9), wherein 
     in the filter, filters having different thicknesses and corresponding to red, green, and blue pixels, are arranged in a Bayer arrangement, and the green filters are linked between pixels. 
     (11) 
     The image pickup element according to any one of (8) to (10), wherein 
     the filter is formed of an organic material. 
     (12) 
     The image pickup element according to any one of (8) to (11), wherein 
     the non-planar layer has an organic film which is formed on the filter and has a non-planar light incident surface. 
     (13) 
     The image pickup element according to (12), wherein 
     heights of projections and recesses of a light incident surface of the organic film are lower than heights of projections and recesses of a light incident surface of the filter. 
     (14) 
     The image pickup element according to (12) or (13), wherein 
     the refractive index of the organic film is between the refractive index of the filter and the refractive index of the microlens. 
     (15) 
     The image pickup element according to any one of (8) to (14), wherein 
     the non-planar layer has an inter-pixel light shield film. 
     (16) 
     The image pickup element according to (15), wherein 
     the non-planar layer has projections and recesses on the light incident surface due to a difference in height between the filter and the inter-pixel light shield film. 
     (17) 
     The image pickup element according to any one of (1) to (16), wherein 
     a chip size package structure is formed. 
     (18) 
     An image pickup device including: 
     an image pickup element which captures an image of an object, and outputs the image of the object as an electrical signal; and 
     an image processing unit which processes the image of the object obtained by the image pickup element, 
     wherein the image pickup element includes
         a non-planar layer which has a non-planar light incident surface in a light receiving region, and   a microlens of an inorganic material which is provided on a side of the light incident surface of the non-planar layer, and collects incident light.
 
(19)
       

     A manufacturing device including: 
     a non-planar layer forming unit which forms a non-planar layer having a non-planar light incident surface in a light receiving region of an image pickup element; 
     an inorganic film forming unit which forms an inorganic film on a side of the light incident surface of the non-planar layer formed by the non-planar layer forming unit; 
     a planarization film forming unit which forms a planarization film on a side of a light incident surface of the inorganic film formed by the inorganic film forming unit; 
     a resist forming unit which forms a resist on a side of a light incident surface of the planarization film formed by the planarization film forming unit; 
     a thermal reflow process unit which performs a thermal reflow process on the image pickup element on which the resist has been formed by the resist forming unit; and 
     an etching process unit which performs etching on the image pickup element on which the thermal reflow process has been performed by the thermal reflow process unit. 
     (20) 
     A method for manufacturing a manufacturing device which manufactures an image pickup element, the method including: 
     by the manufacturing device,
         forming a non-planar layer having a non-planar light incident surface in a light receiving region of an image pickup element,   forming an inorganic film on a side of the light incident surface of the non-planar layer formed,   forming a planarization film on a side of a light incident surface of the inorganic film formed,   forming a resist on a side of a light incident surface of the planarization film formed,   performing a thermal reflow process on the image pickup element on which the resist has been formed, and   performing etching on the image pickup element on which the thermal reflow process has been performed.       

     REFERENCE SIGNS LIST 
     
         
           100  image pickup device 
           121  image pickup region 
           132  color filter 
           133  microlens 
           171  non-planar film 
           200  manufacturing device 
           202  manufacture unit 
           231  light receiving interconnect layer forming unit 
           232  filter forming unit 
           233  first inorganic film forming unit 
           234  planarization film forming unit 
           235  resist pattern forming unit 
           236  thermal reflow process unit 
           237  etchback process unit 
           421  anti-reflection film 
           441  buried color filter 
           452  inter-pixel light shield film