JP2007201266A - Micro-lens, its process for fabrication, solid imaging element using the micro-lens, and its process for fabrication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro-lens in which a topography variation of the micro-lens is reduced, which is stabilized and is a high micro-lens of condensing efficiency with sufficient reproducibility, and to provide a solid imaging element which is stabilized and is reliable at a high sensitivity. <P>SOLUTION: The micro-lens is equipped with a plurality of lens sides arranged so that each of photoelectric conversion areas is arranged oppositely for constituting a pixel. The lens comprises a wall 61 which has a concave surface having a first refractive index prepared in a lattice shape so that, corresponding to the formation pitch of the lens side of the micro-lens, it stands up to a region between the lenses corresponding to the formation pitch of the lens side of the micro-lens, and a lens 60 having the second refractive index higher than the primary refractive index, prepared so that a contact may be carried out to the concave surface of the wall, and allocated to each region surrounded by the wall. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a microlens, a manufacturing method thereof, a solid-state imaging device using the microlens, and a manufacturing method thereof, and particularly relates to shape control of the microlens.

  A solid-state imaging device using a CCD used for an area sensor or the like includes a photoelectric conversion unit including a photodiode and a charge transfer unit including a charge transfer electrode for transferring a signal charge from the photoelectric conversion unit. . A plurality of charge transfer electrodes are arranged adjacent to each other on a charge transfer path formed on the semiconductor substrate, and are sequentially driven.

  In recent years, with the miniaturization of cameras, demands for higher resolution and higher sensitivity are increasing in solid-state imaging devices, and the number of imaging pixels is increasing to more than gigapixels.

  In order to improve the sensitivity, various structures have been proposed in which a microlens is provided on the pixel surface to increase the light collection efficiency to the photodiode.

  For example, as shown in FIG. 11, an intra-layer lens that also serves as a passivation film is formed on the planarizing layer immediately above the photodiode portion constituting the photoelectric conversion unit, and a planarizing film (transparent film) is further formed thereon. A structure in which an optical film), a color filter, a planarizing film, and an on-chip lens are sequentially formed has been proposed.

  Conventionally, when manufacturing a solid-state imaging device using an on-chip lens, after forming a microlens pattern made of a transparent thermosoftening resin, which is a microlens base material, on a photoelectric conversion unit using photolithography technology, The microlens pattern is thermally reflowed by heating to form a microlens.

  By the way, the area between the lenses becomes an invalid area that does not contribute to photoelectric conversion because light passing therethrough is not guided onto the photodiode. Therefore, as a method of narrowing the lens interval, there is a method in which a substance that expands on the planarizing film is processed into a lens shape with an adjacent interval, and this is expanded so that the lens interval becomes zero. It has been proposed (Patent Document 1).

JP-A-6-252372

  However, in the microlens manufacturing process described above, a microlens pattern made of a thermosoftening translucent material is softened by heat, so that the shape of the microlens obtained is the thermal history of the microlens base material. It is determined by the surface state of the planarizing layer, the film thickness, dimensions, etc. of the microlens pattern. For this reason, variations in the shape of the microlens 60 occur as shown in FIG. 12 due to variations in the temperature at the time of thermal reflow and the size / film thickness of the microlens pattern. For example, the temperature is 1 degree and the time is in seconds. Even if it changes, it will fluctuate greatly. In addition, since the reproducibility with respect to the thermal history after the microlens formation is low, the height of the lens is likely to fluctuate, and there is a problem that a highly condensing lens cannot be formed with good reproducibility.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a microlens that reduces the variation in the shape of the microlens and has high light collection efficiency with high reproducibility.
It is another object of the present invention to provide a solid-state imaging device that is stable, highly sensitive, and reliable.

The present invention is a microlens having a plurality of lens surfaces arranged so as to face each of a plurality of photoelectric conversion regions constituting a pixel, each corresponding to the formation pitch of the lens surfaces of the microlens. A wall portion having a concave surface having a first refractive index provided in a lattice shape so as to stand up in an inter-lens region of the lens, and provided so as to abut on the concave surface of the wall portion and surrounded by the wall portion And a lens portion having a second refractive index higher than the first refractive index, which is filled in each region.
With this configuration, since the lens portion is formed by filling the wall portion that has been subjected to shape processing in advance, it is possible to reduce variation in shape and provide a microlens having a constant shape stably. .

The present invention includes the microlens in which the wall portion is formed of a first resin.
With this configuration, since the wall portion is made of (first) resin, shape control can be easily performed by melting. According to this configuration, the controllability is greatly improved because it is only necessary to control the round shape of the wall, as compared with the conventional microlens in which the lens shape itself is obtained by melting.

According to the present invention, in the microlens, the wall portion includes an inorganic film.
With this configuration, it is possible to provide a microlens having high mechanical strength and high reliability. In this case, after forming an inorganic film such as silicon oxide for forming the wall portion, the wall portion is formed with a resist, and this is used as a mask to etch back the shape of the wall portion formed with the resist. By transferring to the inorganic film, the wall portion can be formed with good controllability.

According to the present invention, in the above microlens, the lens portion includes a second resin.
With this configuration, since the lens portion can be formed simply by filling the wall portion with the second resin, it is possible to easily form the lens portion having desired optical characteristics.

According to the present invention, in the microlens, the lens portion includes an inorganic film.
With this configuration, the mechanical strength can be improved. In particular, the mechanical strength is greatly improved by forming the wall portion with an inorganic film and the lens portion with an inorganic film.

The present invention includes the above microlens in which the wall portion is formed of a silicon oxide film and the lens portion is formed of a silicon nitride film.
With this configuration, the optical characteristics and mechanical strength are improved, and the element portion is covered with a two-layer film of a silicon oxide film and a silicon nitride film, so that the insulation and moisture resistance can be improved. Can do.

The present invention includes the above microlens in which a difference in refractive index between the wall portion and the lens portion is 0.4 or more.
With this configuration, it is possible to further improve the light collection efficiency.

The present invention is a method of manufacturing a microlens that is arranged to face each of a plurality of photoelectric conversion regions constituting a pixel and includes a plurality of lens surfaces, and corresponds to the formation pitch of the lens surfaces of the microlenses. Forming a lattice-shaped resist pattern having a first refractive index so as to stand in the inter-lens region of each lens, and forming the wall portion having a concave surface by melting the resist pattern A step of processing, and a step of filling the wall portion with a member having a second refractive index to form a lens portion.
With this configuration, it is possible to shape the wall with good controllability, to reduce variations, and to form highly accurate and reliable microlenses with high reproducibility.

According to the present invention, in the microlens manufacturing method, prior to the step of forming the lens portion, etching is performed under an etching condition such that the etching rates of the wall portion and the base layer are equal, and the shape of the wall portion Is transferred to the base layer to form a wall portion made of the base layer.
With this configuration, it is possible to further improve the mechanical strength as compared with the above method.

According to the present invention, in the method for manufacturing a microlens, the step of forming the lens portion includes a step of flattening the surface.
With this configuration, since the surface is flat, it can be applied as an in-layer lens.

A solid-state imaging device according to the present invention includes a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting pixels, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and The microlens is mounted on the surface of the substrate on which the peripheral circuit portion including the wiring layer connected to the charge transfer portion is formed.
With this configuration, a microlens having a stable and constant shape is mounted, and it is possible to suppress characteristic variation and provide a highly reliable solid-state imaging device.

The present invention provides a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and the charge transfer unit. On the surface of the substrate on which the peripheral circuit portion including the wiring layer to be connected is formed, the first surface provided in a lattice shape so as to stand up in the inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens. A wall portion having a concave surface having a refractive index of 1, and a wall having a higher refractive index than the first refractive index, which is provided in contact with the concave surface of the wall portion and filled in each region surrounded by the wall portion. And a step of aligning and fixing a microlens having a lens portion having a refractive index of 2 so as to correspond to the photoelectric conversion region.
With this configuration, since the microlens is formed and then adhered to the surface of the substrate on which the solid-state imaging device is formed, the microlens can be formed without damaging the solid-state imaging device.

The present invention provides, on a surface of a substrate, a photoelectric conversion unit including a plurality of photoelectric conversion regions constituting pixels, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, Forming a microlens including a step of forming a peripheral circuit portion including a wiring layer connected to the charge transfer portion, and a step of forming a microlens on each of the photoelectric conversion regions on the substrate. Forming a lattice-like resist pattern having a first refractive index so that the process stands up in an inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens; and A step of melting and forming a wall portion having a concave surface, and a step of filling a member having a second refractive index into the wall portion to form a lens portion.
According to this configuration, it is possible to shape the wall with good controllability, to reduce variations, and to form a highly accurate and reliable microlens with high reproducibility.

In the method for manufacturing a solid-state imaging device according to the present invention, prior to the step of forming the wall portion, etching is performed under an etching condition such that etching rates of the wall portion and the base layer are equal, A step of transferring the shape to the base layer to form a wall portion made of the base layer.
According to this configuration, by forming the underlayer with a desired material, it is possible to shape the wall with high controllability by processing the shape by transfer, thereby reducing variation and achieving high accuracy. A highly reliable microlens can be formed with good reproducibility.

According to the present invention, in the method for manufacturing a solid-state imaging device, the step of forming the lens portion includes a step of flattening the surface.
According to this configuration, a solid-state imaging device having a flat surface can be formed with good controllability, and can be applied as an in-layer lens.

  According to the present invention, it is possible to provide a microlens having a desired curvature stably with reduced variation in shape. Therefore, it is possible to provide a solid-state imaging device that has excellent light collection characteristics, high sensitivity, and high reliability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 and 2 are diagrams showing a solid-state imaging device on which the microlens according to Embodiment 1 of the present invention is mounted. FIG. 1 is a cross-sectional view, and FIG. 2 is a schematic plan view. FIG. 1 is a schematic cross-sectional view taken along line AA in FIG.
In the present embodiment, as shown in FIG. 1, a microlens M having a plurality of lens surfaces arranged to face each of a plurality of photoelectric conversion regions constituting a pixel is replaced with a lens surface of the microlens. A wall portion 61 having a concave surface having a first refractive index provided in a lattice shape so as to stand in an inter-lens region of each lens corresponding to the formation pitch, and abutting on the concave surface of the wall portion 61 And a resin lens portion 60 having a second refractive index, which is provided and filled in each region surrounded by the wall portion. The lens portion is configured to have a higher refractive index than the wall portion 61 made of a high refractive index photosensitive resin having heat or ultraviolet crosslinkability, and constitutes a concave lens having a flat upper surface. Examples of the material film having a high refractive index and high photosensitivity include those having a refractive index in the visible light region of about 1.6. Specific examples include one or a mixture of two or more of polyimide, polyalkyl methacrylate, polystyrene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, polyvinyl naphthalene, polyvinyl carbazole and the like. Further, in order to further improve the light collection efficiency, a material having a refractive index higher than these materials (preferably a refractive index difference of 0.4 or more), such as a material having a refractive index of 2 or more, specifically Specifically, an inorganic material, further an inorganic oxide, more specifically zinc oxide, titanium oxide, tin oxide, or the like may be added.
These material films can be left only on the top of the photoelectric conversion portion by known photolithography and etching processes.

  The region other than the microlens has a usual structure, but prior to the description of the method of forming the microlens, the solid-state imaging device will be described first. In the solid-state imaging device used here, photodiodes 30 as photoelectric conversion units are arrayed on the surface of an n-type silicon substrate 1, and signal charges generated in the photodiodes 30 are arranged in the column direction (Y in FIG. 2). The charge transfer section 40 for transferring in the direction) is formed by meandering between a plurality of photodiode rows composed of the plurality of photodiodes 30 arranged in the column direction. Then, the odd-numbered photodiode rows are formed so as to be shifted in the direction of approximately half the array pitch of the photodiodes 30 arranged in the column direction with respect to the even-numbered photodiode rows.

  The charge transfer unit 40 includes a plurality of charge transfer channels 33 formed in the column direction of the surface portion of the silicon substrate 1 corresponding to each of the plurality of photodiode columns, and a charge transfer formed in the upper layer of the charge transfer channel 33. It includes an electrode 3 (first layer electrode 3a, second layer electrode 3b) and a charge readout region 34 for reading out charges generated in the photodiode 30 to the charge transfer channel 33. The charge transfer electrode 3 has a meandering shape extending in the row direction (X direction in FIG. 3) as a whole between a plurality of photodiode rows composed of a plurality of photodiodes 30 arranged in the row direction. . Here, the charge transfer electrode 3 is a single layer electrode structure in which a second layer electrode is formed on the first layer electrode via the interelectrode insulating film 5 and flattened by CMP, but is limited to the single layer electrode structure. Instead, it may be a two-layer electrode structure in which a part of the first layer electrode is covered by the second layer electrode.

  As shown in FIG. 2, a p-well layer 1P is formed on the surface of the silicon substrate 1, an n-region 30b forming a pn junction is formed in the p-well layer 1P, and a p-region 30a is formed on the surface. The photodiode 30 is configured, and the signal charge generated in the photodiode 30 is accumulated in the n region 30b.

  The photodiode 30 is formed with a charge transfer channel 33 composed of an n region at a slight distance (to the right in FIG. 3). A charge readout region 34 is formed in the p-well layer 1P between the n region 30b and the charge transfer channel 33.

A gate oxide film 2 is formed on the surface of the silicon substrate 1, and a first electrode 3 a and a second electrode 3 b are formed on the charge readout region 34 and the charge transfer channel 33 via the gate oxide film 2. The An interelectrode insulating film 5 is formed between the first electrode 3a and the second electrode 3b. Adjacent to the vertical transfer channel 33 (to the right in FIG. 3), a channel stop 32 made of a p ⁺ region is provided, and is separated from the adjacent photodiode 30.

  An insulating film 6 such as a silicon oxide film and an antireflection layer 7 are formed on the charge transfer electrode 3. Further, a light shielding film 8, an insulating film made of BPSG (borophosphosilicate glass), 9, P-SiN An insulating film (passivation film) 10 and an under-filter planarizing film 11 made of a silicon oxide film are formed. The light shielding film 8 is provided except for the opening of the photodiode 30. An on-filter planarizing film 51 made of an insulating transparent resin or the like is provided on the upper layer of the color filter 50 (50G, 50B, 50R, 50T). A microlens M is provided on the upper layer.

  In the solid-state imaging device according to the present embodiment, signal charges generated in the photodiode 30 are accumulated in the n region 30b, and the accumulated signal charges are transferred in the column direction by the charge transfer channel 33, and the transferred signals are transferred. The charge is transferred in the row direction by a horizontal charge transfer path (HCCD) (not shown), and a color signal corresponding to the transferred signal charge is output from an amplifier (not shown). In other words, on the silicon substrate 1, a solid-state imaging device unit that is a region including a photoelectric conversion unit, a charge transfer unit, an HCCD, and an amplifier, and a peripheral circuit that is a region where peripheral circuits (PAD unit and the like) of the solid-state imaging device are formed. Are formed to constitute a solid-state imaging device.

  According to the above configuration, since the lens portion is formed by filling the wall portion that has been processed in advance with the resin, the variation in shape is reduced, and a microlens having a stable and constant shape is provided. Is possible. Further, since the wall portion is made of resin, the shape can be easily controlled by melting. Therefore, as compared with the conventional microlens that obtains the lens shape itself by melting, it is only necessary to control the round shape of the wall, so that the controllability is greatly improved.

Next, the manufacturing process of the above-described solid-state imaging device will be described.
In this method, a lattice-like resist pattern is formed so as to stand up in the inter-lens area of each lens corresponding to the formation pitch of the lens surface of the microlens, the resist pattern is melted, and a wall portion having a concave surface is formed. After the shape processing is performed so as to constitute, the wall portion is filled with resin to form a lens portion.
In manufacturing, conventional methods other than the microlens manufacturing method are used. First, the manufacturing process up to the formation of the color filter will be described.
Impurities are introduced into the surface of the n-type silicon substrate 1 to form a p-well layer 1P, a charge transfer channel 33, a charge readout region 34, a channel stop layer 32, and the like, and then a gate oxide film 2 is formed. Subsequently, a first conductive film constituting the first layer electrode 3a is formed on the gate oxide film 2, and patterning is performed to form the first layer electrode 3a and peripheral circuit wiring. Next, an insulating film 5 made of a silicon oxide film is formed around the first layer electrode 3a, and a second conductive film constituting the second layer electrode 3b is formed thereon. Next, the second conductive film 3b is planarized by CMP and patterned to form the second layer electrode 3b. Next, after forming an insulating film 6 so as to cover these charge transfer electrodes 3, an n region 30b and a p region 30a in the photodiode region are formed, an antireflection film is formed, and light reception in the photodiode region is further performed. A light shielding film 8 is formed of a tungsten film or the like so as to open in the region. Next, an insulating film 9 is formed and planarized by high temperature reflow.

Next, after forming a contact hole in the upper part of the peripheral circuit of the insulating film 9, a metal film such as aluminum is formed and patterned to form a bonding pad (not shown). Then, a passivation film 10 made of a silicon nitride film is formed by the CVD method, and the passivation film 10 on the bonding pad is selectively removed by etching to form an opening to expose the bonding pad. Thereafter, sintering is performed in an inert gas atmosphere containing H _2, and then a planarizing film 11 having a film thickness of 0.5 to 2.0 μm is formed by spin coating or scan coating. Here, in order to avoid confusion with other planarization films, this planarization film is referred to as an under-filter planarization film 11. Then, the color filter layers 50G, 50B, and 50R and the filter flattening film 51 are sequentially formed. The manufacturing process so far is a usual method. As the planarizing film 11 under the filter, a resist material transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) is used. However, when the film forming process of the filter base material layer of the color filter layer becomes high temperature, the under-filter planarizing film may be an inorganic film such as a silicon oxide film instead of an organic film. Moreover, when there are few unevenness | corrugations of a lower layer, the under filter planarization film | membrane 11 does not need to be.

Next, the manufacturing process of the microlens will be described in detail with reference to the drawings.
3A to 3D are views showing a manufacturing process of a microlens. Here, for simplification, a region such as the insulating film 9 including the planarizing film 51 on the filter is shown as the intermediate layer 70.

First, as shown in FIG. 3A, a resist 61 is applied on the intermediate layer 70 on the solid-state imaging device substrate on which the photoelectric conversion unit 30 and the charge transfer unit 40 are formed. Then, through patterning by photolithography, as shown in FIG. 3B, patterning is performed so as to form a lattice shape having a width of 2 to 3 microns and a height of 1 micron (see FIG. 7). This lattice size can be miniaturized using a well-known photolithography technique as the pixel size is miniaturized.
Thereafter, it is fluidized at a melting temperature of 200 ° C., and as shown in FIG. 3C, a pattern of this resist is formed so as to have a desired curved shape, and a wall portion 61 is obtained.

  In this way, the concave portion of the obtained wall portion 61 is filled with a high refractive index photosensitive resin, which is a material having a higher refractive index, and a lens surface 60 is formed as shown in FIG.

  As described above, according to the method of the present embodiment, the shape of the wall can be processed with good controllability, the variation can be reduced, and a highly accurate and reliable microlens can be formed with high reproducibility. It becomes possible. .

  In this embodiment, the solid-state imaging device having a configuration in which photodiodes are arranged in a honeycomb shape has been described. However, the present invention is not limited thereto, and a configuration in which a plurality of photodiodes are arranged in a square lattice shape is described. The present invention can also be applied to other solid-state imaging devices.

  In the first embodiment, the resist pattern for forming the wall portion 61 is patterned so as to form a lattice as shown in FIG. 7, but depending on the selection of the material, the resist pattern may be patterned into another shape, If this is melted, it may be possible to form a lens surface with good condensing characteristics without variation.

  For example, as a modified example, as shown in FIG. 8, there are a grid-like middle part and a thickened shape. In this case, when the resist pattern is melted, the intermediate portion comes into contact first, and the flow at the tip of the melted portion stops here, so that a curved surface with a smaller curvature radius can be formed.

  As another modified example, as shown in FIG. 9, it is also effective to form a resist pattern while leaving a circular portion. In this case, when the resist pattern is melted, the flow on the base surface is stopped in a state where the resist pattern flows uniformly and the flow distance on the base surface is equal, so that a curved surface with less variation can be formed.

  As another modification, as shown in FIG. 10, it is also effective to shape the resist pattern while leaving the octagonal portion. In this case, since the flow distance on the photodiode becomes uniform corresponding to the octagonal photodiode, the variation can be further reduced.

  Furthermore, the wall portion may be filled with an inorganic film such as a high refractive index inorganic polymer to which zinc oxide, titanium oxide, tin oxide or the like is added instead of filling the resin.

(Embodiment 2)
Although the wall portion is made of resin in the first embodiment, the present embodiment is characterized in that the wall portion is made of a silicon oxide film 62, that is, an inorganic film, as shown in FIG. The lens portion is composed of a silicon nitride film 63. A lens formed with this configuration can be applied as an intralayer lens under a color filter. Others are formed in the same manner as the solid-state imaging device shown in the first embodiment.
At the time of manufacturing, the resist pattern R2 is melted and processed in the same manner as in the process shown in FIG. 3 in the first embodiment, and then the resist pattern R2 and silicon nitride as an underlayer are used as a mask. Etching is performed under the etching conditions such that the etching rates are equal to each other, and the shape of the resist pattern is transferred to the base layer to form the wall portion 62 made of the base layer.
According to this configuration, by forming the underlayer with a desired material, it is possible to shape the wall with high controllability by processing the shape by transfer, thereby reducing variation and achieving high accuracy. A highly reliable microlens can be formed with good reproducibility.

Next, the manufacturing process of this microlens will be described.
FIGS. 5A to 5D are views showing a manufacturing process of a microlens. Here, for simplification, a region such as the insulating film 9 including the planarizing film 51 on the filter is shown as the intermediate layer 70.

First, as shown in FIG. 5A, a silicon oxide film 62 is formed by CVD on the intermediate layer 70 on the solid-state imaging device substrate on which the photoelectric conversion unit 30 and the charge transfer unit 40 are formed. A photoresist R2 is applied to the substrate. Then, after patterning by photolithography, as shown in FIG. 5B, patterning is performed so as to form a lattice shape having a width of 2 to 3 microns and a height of 1 micron (see FIG. 7). This lattice size can be miniaturized using a well-known photolithography technique as the pixel size is miniaturized.
Thereafter, the resist R2 is fluidized at a melting temperature of 200 ° C. and a pattern of the resist R2 is formed so as to have a desired curved shape as shown in FIG.

  In this way, using the obtained resist R2 pattern as a mask, etch back is performed under etching conditions such that the etching rates of the resist R2 and the silicon oxide film are equal, and the pattern of the resist R2 is transferred to the silicon oxide. The wall 62 is formed (FIG. 5D).

Then, as shown in FIG. 6A, a silicon nitride film 63 is formed on the wall portion 62 by the CVD method.
Further, as shown in FIG. 6B, a resist R3 is applied to the upper layer and flattened.
Then, as shown in FIG. 6C, the microlens obtained by filling the concave surface of the wall portion 62 made of a silicon oxide film with a silicon nitride film 63 by performing resist etch back to flatten the surface. Complete.

  In the present embodiment, since the microlens is formed by filling the concave portion of the wall portion formed of the silicon oxide film with the silicon nitride film to form the lens portion 63, the manufacturing variation is suppressed, and the optical lens is optically formed. Properties and mechanical strength are improved. In addition, since the element portion is covered with a two-layer film of a silicon oxide film and a silicon nitride film, insulation and moisture resistance can be improved.

  In addition, if the resist pattern before fluidization for forming the wall portion and the fluidization process are simulated at the design stage to determine the optimum pattern according to the material, the structure of the pixel becomes complicated. It is also possible to easily improve the quality of the lens.

  In the above embodiment, the microlens is formed on the upper layer after the solid-state image sensor is formed on the semiconductor substrate. However, the microlens layer is formed as a separate body, and this is adhered to the solid-state image sensor substrate. You may make it do.

  According to the microlens of the present invention, shape variation can be reduced and high quality can be achieved. Therefore, the microlens is useful as a color filter for a solid-state imaging device in an electronic device such as a mobile phone.

Structure explanatory drawing of the solid-state image sensor using the microlens of Embodiment 1 of this invention 1 is a plan view of a solid-state imaging device according to a first embodiment of the present invention. The figure which shows the manufacturing process of the solid-state image sensor of this Embodiment 1. Structure explanatory drawing of the solid-state image sensor using the micro lens of Embodiment 2 of this invention The figure which shows the manufacturing process of the solid-state image sensor of Embodiment 2 of this invention. The figure which shows the manufacturing process of the solid-state image sensor of Embodiment 2 of this invention. The figure which shows the resist pattern used for the shape process of the micro lens of Embodiment 1 of this invention The figure which shows the modification of the resist pattern used for the shape process of the micro lens of Embodiment 1 of this invention The figure which shows the modification of the resist pattern used for the shape process of the micro lens of Embodiment 1 of this invention The figure which shows the modification of the resist pattern used for the shape process of the micro lens of Embodiment 1 of this invention The figure which shows the solid-state image sensor of a prior art example The figure which shows the solid-state image sensor of a prior art example

Explanation of symbols

1 n-type silicon substrate 2 gate oxide film 3a first electrode 3b second electrode 5 interelectrode insulating film 6 insulating film 7 antireflection layer 8 light shielding film 9 insulating (BPSG) film 10 passivation film 11 planarizing films 50B and 50R , 50G color filter 51 planarizing film 60 on the filter micro lens (lens part)
61 Wall part 62 Wall part 63 Lens part 70 Intermediate layer 80 showing a region such as the insulating film 9 including the planarizing film 51 on the filter Intermediate layer showing a region including the insulating film 9

Claims (15)

A microlens having a plurality of lens surfaces arranged to face each of a plurality of photoelectric conversion regions constituting a pixel,
A wall portion having a concave surface having a first refractive index provided in a lattice shape so as to stand up in an inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens;
A lens unit provided so as to be in contact with the concave surface of the wall part and filled with each region surrounded by the wall part and having a second refractive index higher than the first refractive index. lens. The microlens according to claim 1,
The wall portion is a microlens made of a first resin. The microlens according to claim 1,
The wall portion is a microlens made of an inorganic film. The microlens according to claim 2 or 3,
The lens unit is a microlens made of a second resin. The microlens according to claim 2 or 3,
The lens part is a microlens made of an inorganic film. The microlens according to claim 1,
The wall portion is made of a silicon oxide film, and the lens portion is a microlens made of a silicon nitride film. The microlens according to claim 1,
A microlens in which a difference in refractive index between the wall portion and the lens portion is 0.4 or more. A method of manufacturing a microlens that is disposed so as to face each of a plurality of photoelectric conversion regions constituting a pixel and includes a plurality of lens surfaces,
Forming a lattice-like resist pattern having a first refractive index so as to stand up in an inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens;
Melting the resist pattern and performing a shape process to form a concave wall; and
A step of filling a member having a second refractive index in the wall portion to form a lens portion. It is a manufacturing method of the micro lens according to claim 8,
Prior to the step of forming the lens portion, etching is performed under etching conditions such that the etching rates of the wall portion and the underlayer are equal, and the shape of the wall portion is transferred to the underlayer to form a wall made of the underlayer. A method of manufacturing a microlens including a step of forming a portion. It is a manufacturing method of the micro lens according to claim 8 or 9,
The step of forming the lens portion is a method of manufacturing a microlens including a step of flattening the surface. A photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and a wiring connected to the charge transfer unit On the surface of the substrate on which the peripheral circuit part including the layer is formed,
A solid-state image sensor on which the microlens according to claim 1 is mounted. A photoelectric conversion unit including a plurality of photoelectric conversion regions constituting a pixel, a charge transfer unit including a charge transfer electrode that transfers charges generated in the photoelectric conversion unit, and a wiring connected to the charge transfer unit On the surface of the substrate on which the peripheral circuit part including the layer is formed,
A wall portion having a concave surface having a first refractive index provided in a lattice shape so as to stand in an inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens,
A lens unit provided so as to be in contact with the concave surface of the wall part and filled with each region surrounded by the wall part and having a second refractive index higher than the first refractive index. A method for manufacturing a solid-state imaging device, including a step of positioning and fixing a lens so as to correspond to the photoelectric conversion region. A photoelectric conversion unit having a plurality of photoelectric conversion regions constituting pixels on a surface of a substrate, a charge transfer unit having a charge transfer electrode for transferring charges generated by the photoelectric conversion unit, and the charge transfer unit Forming a peripheral circuit portion including a wiring layer connected to
Forming a microlens on each of the photoelectric conversion regions on the substrate,
Forming the microlens,
Forming a lattice-like resist pattern having a first refractive index so as to stand up in an inter-lens region of each lens corresponding to the formation pitch of the lens surface of the microlens;
Melting the resist pattern and performing a shape process to form a concave wall; and
And a step of filling a member having a second refractive index in the wall portion to form a lens portion. It is a manufacturing method of the solid-state image sensing device according to claim 13,
Prior to the step of forming the wall portion, etching is performed under an etching condition such that the etching rates of the wall portion and the underlayer are equal, and the shape of the wall portion is transferred to the underlayer to form a wall made of the underlayer. A method for manufacturing a solid-state imaging device including a step of forming a portion. It is a manufacturing method of the solid-state image sensing device according to claim 13 or 14,
The step of forming the lens portion is a method for manufacturing a solid-state imaging device, including a step of flattening the surface.

Images