JP2007048967A - Solid-state image sensing device, manufacturing method thereof and lens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image sensing device which has a structure capable of readily forming a microlens array of high accuracy, and to provide its manufacturing method. <P>SOLUTION: In order to prevent crosstalks between adjacent pixels by oblique incidence light, clock wiring 38 used as a light-shielding member is arranged on the boundary of a light receiving pixel. The clock wiring 38 is embedded to the groove 62a arranged in an interlayer insulating film 62. The upper surface of the clock wiring 38 is retreated from the surface of the interlayer insulation film 62, and the interlayer insulating film 64 is laminated on this. The interlayer insulating film 64 is depressed in the position of the groove 62a, a convex part of the interlayer insulating film 64 is formed on each light-receiving pixel, and a microlens is constituted by this interlayer insulating film 64. This microlens array is arranged with self alignment at the receiving pixel, based on the groove 62a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device having a microlens array, a manufacturing method thereof, and a lens array.

  In recent years, an image pickup apparatus using a CCD image sensor or a CMOS image sensor is required to have a high pixel count. When the number of pixels of the imaging device is increased, the entire device becomes large. However, in a small imaging device mounted on a mobile device such as a mobile phone, the entire device cannot be enlarged. For this reason, in a small-sized image pickup device, an increase in the number of pixels is realized by reducing the area of each light receiving pixel of the solid-state image pickup device.

  When the area of each light receiving pixel is reduced, the area for receiving light corresponding to the subject is reduced, so that the sensitivity of the solid-state imaging device is lowered. As a countermeasure against this, a method of forming a microlens corresponding to each light receiving pixel of a solid-state imaging device is known. By forming the microlens, light in a region wider than the area of the light receiving pixel can be collected and information charges can be generated, so that the sensitivity of the solid-state imaging device can be improved.

  As a conventional method for forming a microlens on a solid-state imaging device, for example, an organic film such as a resist is patterned so that a convex portion comes to the position of a light receiving pixel, and this is thermally reflowed to obtain a rounded cross-sectional shape. The lens is used. It has also been proposed to form a microlens using an inorganic film such as a silicon oxide film or a silicon nitride film. In the following Patent Document 1, an inorganic film is patterned so that a convex portion comes to the position of a light receiving pixel, and this is irradiated with gas ions to round the cross-sectional shape to form a lens and to reduce the lens interval. Technology is disclosed.

  FIG. 7 is a schematic device cross-sectional view illustrating a method for manufacturing a microlens array in a conventional solid-state image sensor. On the surface of the semiconductor substrate 2 in which the p-well 4 is formed, a channel region 6 into which n-type impurities are implanted and a channel isolation region 8 into which p-type impurities are implanted are formed corresponding to the light receiving pixels. A stack 10 such as a gate electrode and an interlayer insulating film is formed on the substrate 2, and a wiring layer is stacked and patterned thereon to form a clock wiring 12 for applying a transfer clock to the gate electrode. A silicon oxide film 14 and a silicon nitride film 16 are stacked as insulating films. In the silicon nitride film 16, the boundary of the light receiving pixel is etched by a photolithography technique, and a convex portion 18 corresponding to the position of the light receiving pixel is formed (FIG. 7A). By irradiating the silicon nitride film 16 with gas ions, the corners of the convex portions 18 are cut and a rounded lens 20 is formed (FIG. 7B).

Another problem with solid-state imaging devices is color mixing between pixels due to oblique incidence of light. This color mixture is caused when incident light from an oblique direction that has passed through an adjacent color filter enters a light receiving pixel that is different from the light receiving pixel that should be incident. As a conventionally known countermeasure to this problem, there is a technology in which a CCD image sensor uses a wiring layer stacked on an interlayer insulating film to constitute a light shielding member that prevents oblique incidence of light on adjacent pixels. Then, a clock wiring and a dummy wiring for applying a transfer clock to the transfer electrode are arranged along the boundary of the light receiving pixels. The clock wiring 12 in FIG. 7 is such a light shielding member.
JP 2005-148166 A

  In the conventional method for manufacturing a microlens array, an organic film or an inorganic film constituting the microlens array is formed and then patterned in accordance with the arrangement of the light receiving pixels, as in the process of forming the convex portion 18. Contains. Therefore, due to misalignment during the patterning, it is difficult to accurately arrange the lens with respect to the light receiving pixel, and there is a problem that the incident efficiency of the light collected by the lens on the photoelectric conversion region of the pixel may be reduced. there were.

  In addition, there is a problem that the number of processes increases because an additional process for forming the irregularities corresponding to the lens is required.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid-state imaging device having a structure capable of easily forming a microlens array with high accuracy and a method for manufacturing the same.

  The solid-state imaging device according to the present invention includes a plurality of light receiving pixels arranged on one main surface of a semiconductor substrate, a base light transmitting film laminated on the light receiving pixels, and the light reception on the surface of the base light transmitting film. A pixel separation light shielding member embedded in a groove formed at a position corresponding to the boundary of the pixel, and a lens formation film which is a light transmission film laminated on the respective surfaces of the pixel separation light shielding member and the base light transmission film, The pixel separation light blocking member fills the groove to a height lower than the surface of the base light transmission film.

  In another solid-state imaging device according to the present invention, at least a part of the pixel separation light-shielding member constitutes a clock wiring to which a transfer clock for transferring information charges generated in the light receiving pixels is applied.

  In the solid-state imaging device according to another aspect of the invention, the plurality of light receiving pixels are arranged in a matrix, and the groove is between a boundary between the light receiving pixels adjacent in the column direction and between the light receiving pixels adjacent in the row direction. Provided at each boundary.

  A method for manufacturing a solid-state image pickup device according to the present invention is a method for manufacturing a solid-state image pickup device having a microlens array corresponding to a plurality of light-receiving pixels arranged on one main surface of a semiconductor substrate. A groove forming step of forming a groove at a position corresponding to a boundary of the light receiving pixel on the surface of the laminated first light transmission film, and a step of depositing a light shielding film in the groove and on the surface of the first light transmission film Etching back the light shielding film to a partial depth of the groove to form a pixel separation light shielding member with the light shielding film selectively left in the groove; and the pixel separation light shielding member and the first light. Laminating a second light transmission film on the surface of the transmission film to form the microlens array.

  Another method for manufacturing a solid-state imaging device according to the present invention is a method for manufacturing a solid-state imaging device having a microlens array corresponding to a plurality of light-receiving pixels arranged on one main surface of a semiconductor substrate. A groove forming step of forming a groove at a position corresponding to the boundary of the light receiving pixel on the surface of the first light transmission film laminated thereon, and depositing a light shielding film in the groove and on the surface of the first light transmission film Etching back the light shielding film to a partial depth of the groove, forming a pixel separation light shielding member with the light shielding film selectively left in the groove, the pixel separation light shielding member, and the first A step of laminating a second light transmissive film on the surface of the one light transmissive film, a step of irradiating gas ions toward the second light transmissive film, and forming the microlens array by the second light transmissive film; .

  The lens array according to the present invention includes a base light-transmitting film laminated on a substrate, a separation light-shielding member embedded in a groove formed at a position surrounding a predetermined region on the surface of the base light-transmitting film, and the separation A lens forming film that is a light transmissive film laminated on the surface of each of the light shielding member and the base light transmissive film, and the pixel separation light shielding member has the groove formed to a height lower than the surface of the base light transmissive film. It is to fill.

  According to the present invention, the light shielding member is embedded in the groove formed in the light transmission film. At this time, the upper surface of the light shielding member is formed at a height lower than the surface of the light transmission film in which the groove is formed. That is, a part of the depth of the groove is left as a step on the surface of the light transmission film. Since the groove is formed at a position corresponding to the boundary of the light receiving pixel, if another light transmissive film is laminated on the light transmissive film on which the step of the groove is left, the light transmissive film laminated later will be A convex lens-shaped cross section whose height decreases from a position corresponding to the center of the light receiving pixel to a position corresponding to the boundary is formed on each light receiving pixel. That is, according to the present invention, the position of the lens formed by the light transmissive film laminated later is determined in a self-aligned manner with respect to the light receiving pixel by using the groove for embedding the light shielding member. As a result, the arrangement accuracy with respect to the light receiving pixels can be improved. Further, the light transmissive film to be laminated later basically forms a lens shape simply by being laminated on the base, and it is possible to omit a process such as a separate patterning, thereby simplifying the manufacturing process. In addition, the gap between the lenses becomes narrower than the width of the groove due to the effect that the light-transmitting film to be laminated later flattens the unevenness of the base, and accordingly, the condensing area of the lens is increased accordingly. Further, by irradiating the light-transmitting film laminated later with gas ions and breaking the step of the light-transmitting film, the curvature of the cross-section can be smoothed, and the cross-section of the light-transmitting film can be made suitable as a lens. At the same time, the outer edge of the lens is enlarged and the light collection efficiency can be improved.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[First Embodiment]
This embodiment is a frame transfer type CCD image sensor. FIG. 1 is a schematic plan view showing a schematic configuration of a frame transfer type CCD image sensor. The frame transfer type CCD image sensor 30 includes an imaging unit 30i, a storage unit 30s, a horizontal transfer unit 30h, and an output unit 30d.

  The imaging unit 30i is a part that performs photoelectric conversion corresponding to the irradiated light image, and a plurality of light receiving pixels that generate signal charges corresponding to the amount of incident light are arranged in a matrix. Each column of cells arranged in a matrix in the imaging unit 30i constitutes a vertical CCD shift register. The vertical CCD shift register of the imaging unit 30i includes a plurality of gate electrodes that are passed in the row direction on the substrate, and the signal charges of the respective light receiving pixels are obtained by three-phase transfer clocks φi1 to φi3 applied to the gate electrodes. Vertical transfer. The accumulating unit 30s includes a plurality of light-shielded vertical CCD shift registers. The vertical CCD shift registers of the storage unit 30s are provided corresponding to the vertical CCD shift registers of the imaging unit 30i. The vertical CCD shift registers corresponding to each other of the imaging unit 30i and the storage unit 30s have continuous channels, and drive both of the shift registers in synchronization to transfer the signal charges stored in the imaging unit 30i to the storage unit 30s. be able to. Similar to the imaging unit 30i, the vertical CCD shift register of the storage unit 30s includes a plurality of gate electrodes passed in the row direction, and the three-phase transfer clocks φs1 to φs3 applied to these gate electrodes are used in the storage unit 30s. Signal charge accumulation and vertical transfer are controlled.

  The horizontal transfer unit 30h is composed of a CCD shift register driven by, for example, two-phase transfer clocks φh1 and φh2, and each bit thereof is connected to each output of a plurality of vertical CCD shift registers in the storage unit 30s. The horizontal transfer unit 30h receives signal charges from the storage unit 30s in units of one row, and sequentially transfers the signal charges for one row to the output unit 30d.

  The output unit 30d includes a capacitor and an amplifier that extracts a change in potential of the capacitor. The signal charge output from the horizontal transfer unit 30h is received by the capacitor in 1-bit units, converted into a voltage value, and output as a time-series image signal.

  FIG. 2 is a schematic plan view showing the configuration of the imaging unit 30i. A plurality of CCD shift register channel regions 32 extending in the column direction are separated from each other by a channel stop region 34 in a region corresponding to the imaging unit 30 i on the surface of the semiconductor substrate. A plurality of gate electrodes 36 that are orthogonal to the channel region 32 and arranged in the column direction are stacked on the semiconductor substrate. The gate electrode 36 is formed of a light transmissive material such as polysilicon. On the gate electrode 36, a wiring layer made of a metal film having a high light shielding property and high reflectivity, for example, a tungsten (W) alloy is laminated, and a clock extending along the channel stop region 34 by using a method described later. A wiring 38 is formed. The clock wiring 38 is electrically connected to the gate electrode 36 through the contact hole 40, and a transfer clock can be applied to the gate electrode 36.

  As described above, the vertical CCD shift register constituting the imaging unit 30i is three-phase drive, and the three gate electrodes 36 continuously arranged in the column direction constitute one bit of the shift register. And this bit is matched with the light reception pixel of the imaging part 30i. For example, assuming that one bit is from the gate electrode 36-1 to which the transfer clock φi1 is applied to the gate electrode 36-3 to which the transfer clock φi3 is applied, between the gate electrode 36-1 and the gate electrode 36-3, A boundary between adjacent light receiving pixels in the column direction is located.

  The clock wiring 38 has a protrusion 42 that extends horizontally at the boundary position in the column direction of the light receiving pixels. Incidentally, the clock wirings 38 adjacent in the row direction supply phases different from each other among the transfer clocks φi1 to φi3, so that the protrusion 42 is not connected to the clock wiring 38 on the opposite side. In the configuration of FIG. 2, the protrusions 42 alternately extend from the clock wirings 38 on both sides of the channel region 32 of each vertical CCD shift register. That is, for example, at the pixel boundary between the (2i-1) th row (i is an integer) and the 2ith row, the protrusion 42 extends from one side of the channel region 32, and the 2ith row and the (2i + 1) th row. The protrusion 42 extends from the other side of the channel region 32 at the pixel boundary between the first and second channels.

  On the wiring layer, after a microlens array, which will be described later, is formed, a color filter having color transmission characteristics corresponding to each light receiving pixel is further arranged. For example, here, the color filters are in a Bayer array, and color filters of different colors are arranged in adjacent light receiving pixels.

  Here, when light is incident obliquely at the pixel boundary portion, the light passing through the color filter is not a light receiving pixel associated with the color filter, but a light receiving pixel associated with a color filter adjacent to the color filter. , And color mixing is likely to occur due to this. Further, the light incident on the pixel boundary portion may cause crosstalk between the pixels due to refraction in the interlayer film or the like. The clock wiring 38 and the protrusion 42 described above have a function of preventing such a problem. That is, as described above, the clock wiring 38 and the protrusion 42 thereof are formed using a material having low transmittance, and are disposed on the boundary of the light receiving pixels, so that the oblique incidence of light to the adjacent light receiving pixels is prevented. Blocking and preventing color mixing between the light receiving pixels. In addition, the clock wiring 38 and the protrusion 42 thereof are made of a highly reflective material, so that the light impinging on the side surface is reflected toward the light receiving pixels that should be originally incident, thereby ensuring the light receiving efficiency.

3 and 4 are schematic cross-sectional views showing the structure of the imaging unit 30i, FIG. 3 is a cross-section along the line AA shown in FIG. 2, and FIG. 4 is shown in FIG. It is a cross section along line segment BB. A p-well 52 that is a p-type impurity diffusion layer is formed on the surface side of the semiconductor substrate 50. An n-type impurity is implanted into the p-well 52 to form an n ⁻ that becomes the channel region 32 of each vertical CCD shift register. A region is formed. The channel region 32 constitutes a light receiving pixel that photoelectrically converts received light in cooperation with the p well 52. Between the channel regions 32, a channel stop region 34, which is a p ⁺ region into which a p-type impurity is implanted, is formed.

  A gate electrode 36 is formed on the semiconductor substrate 50 via a gate insulating film 60. On the gate electrode 36, a first interlayer insulating film 62 (for example, a silicon oxide film) formed of a light transmission film is formed. The clock wiring 38 and the protrusion 42 thereof are formed in the interlayer insulating film 62 so as to be embedded in grooves 62a and 62b formed at positions corresponding to the boundaries of the light receiving pixels. The clock wiring 38 is selectively connected to any one of the gate electrodes 36-1 to 36-3 through the contact hole 40, and a transfer clock is applied to the gate electrode 36.

  Here, the clock wiring 38 and the projection 42 thereof do not completely fill the grooves 62 a and 62 b, and the upper surfaces of the clock wiring 38 and the projection 42 are located lower than the surface of the interlayer insulating film 62. That is, a step is left in the grooves 62a and 62b.

  A second interlayer insulating film 64 (for example, a silicon nitride film) composed of a light transmitting film is deposited as a lens film for forming a microlens array on the interlayer insulating film 62 where the step is left. The interlayer insulating film 64 is affected by the unevenness between the underlying interlayer insulating film 62 and the grooves 62 a and 62 b, thereby generating unevenness on the surface. That is, the surface of the interlayer insulating film 64 is recessed at the groove portion, and a convex curved surface is formed between the grooves. Utilizing this shape, a microlens array is formed by the interlayer insulating film 64.

  A color filter 68 is laminated on the interlayer insulating film 64 directly or via a light transmission film 66 having a refractive index lower than that of the interlayer insulating film 64. The color filter 68 includes a plurality of filters 68a such as red (R), green (G), and blue (B), and these filters 68a are regularly arranged corresponding to each light receiving pixel. Further, on the color filter 68, a planarizing film 70 made of, for example, acrylic for planarizing the color filter 68 is laminated.

  In this configuration, the interlayer insulating film 64 is formed of a material having a relatively high refractive index, for example, a silicon nitride film, and the upper layer is formed of a material having a refractive index smaller than that of the interlayer insulating film 64. The convex portion of the interlayer insulating film 64 formed on the light receiving pixels has a lens function of collecting incident light for each light receiving pixel.

  Next, a manufacturing method of the CCD image sensor 30 will be described with reference to FIG. FIG. 5 is a schematic cross-sectional view of the imaging unit 30i for explaining the steps of the manufacturing method. Here, a cross-section along the line BB in FIG. 2 is shown.

  When manufacturing the CCD image sensor 30, first, as shown in FIG. 5A, a p-well 52 is formed on one main surface of the semiconductor substrate 50, and a channel region 32 and a channel are formed on the surface region of the p-well 52. A stop region 34 is formed. Subsequently, a gate electrode 36 is formed on the surface of the channel region 32 and the channel stop region 34 via the gate insulating film 60.

  A first interlayer insulating film 62 is formed on the gate electrode 36 by, eg, plasma CVD. Subsequently, a resist (not shown) is applied on the first interlayer insulating film 62, and the resist is formed into a shape having an opening corresponding to the contact hole 40 by well-known photolithography. Etching by dry etching or the like is performed. As a result, as shown in FIG. 5A, a contact hole 40 that penetrates the first interlayer insulating film 62 and reaches the gate electrode 36 is formed.

  Next, as shown in FIG. 5B, following the above-described etching, for example, etching by dry etching or the like is similarly performed on the first interlayer insulating film 62, and the clock wiring 38 is formed on the surface of the interlayer insulating film 62. A corresponding groove 62a is formed. Although not shown in the drawing, at this time, a groove 62 b corresponding to the protrusion 42 of the clock wiring 38 is also formed on the surface of the interlayer insulating film 62 at the same time.

  Next, as shown in FIG. 5C, the wiring material film 80 (by vapor deposition, sputtering, etc.) is formed on the surface of the first interlayer insulating film 62 including the contact hole 40 and the inner wall surfaces of the grooves 62a and 62b. For example, a film made of a tungsten alloy is formed. Subsequently, as shown in FIG. 5D, the wiring material film 62 is etched back to remove the wiring material film 80 and expose the first interlayer insulating film 62. At this time, by setting a large etch back amount, the upper portion of the wiring material film 80 embedded in the grooves 62a and 62b is removed to a depth in the middle of the grooves 62a and 62b. Thus, by recessing the surface of the wiring material film 80 from the surface of the interlayer insulating film 62, the clock wiring 38 and the protrusions 42 embedded in the grooves 62a and 62b are formed, while the positions of the grooves 62 and 62b are formed. As a result, concaves and convexes are formed in which the surface of the interlayer insulating film 62 becomes convex.

  Using the uneven interlayer insulating film 62 as a base, a second interlayer insulating film 64 is formed by, for example, plasma CVD (chemical vapor deposition) as shown in FIG. 5E. The surface of the interlayer insulating film 64 is uneven depending on the base. That is, in the vicinity of the trenches 62a and 62b, the surface of the interlayer insulating film 64 is recessed as much as the recess formed by overetching the wiring material film 80 is filled. Here, since the film forming process itself of the interlayer insulating film 64 has an effect of flattening the unevenness of the base to some extent, the surface height of the interlayer insulating film 64 is outside the grooves 62a and 62b (that is, above the interlayer insulating film 62). ) Starts to decrease smoothly, and becomes the lowest near the center of the grooves 62a and 62b. Thereby, the surface of the interlayer insulating film 64 on each light receiving pixel can be formed into a convex shape that bends smoothly, and the interlayer insulating film 64 constitutes a microlens array.

  A light transmission film 66 made of a material having a refractive index lower than that of the interlayer insulating film 64 is laminated and planarized directly on the surface of the interlayer insulating film 64 or as shown in FIG. Form corresponding to. Furthermore, a planarizing film 70 made of acrylic, for example, may be formed on the color filter 68.

  In addition, although each process was demonstrated here using FIG. 5 represented about the cross section along line BB of FIG. 2, about the cross section along line AA of FIG. A similar structure is formed in each process.

  According to the configuration of the imaging unit 30i of the CCD image sensor 30 described above, the arrangement of the microlens array formed as the unevenness of the interlayer insulating film 64 is defined by the grooves 62a and 62b. Since the grooves 62a and 62b are arranged on the boundary of the light receiving pixels in order to prevent color mixing between the light receiving pixels due to obliquely incident light, the arrangement of the microlens array is arranged in a self-aligned manner with respect to the arrangement of the light receiving pixels. The In addition, the recesses at the boundary of the light receiving pixels in the interlayer insulating film 62 that cause the unevenness of the microlens array are formed together with the clock wiring 38 and the protrusions 42 thereof, and a separate process of patterning the interlayer insulating film 62 is unnecessary. As a result, the manufacturing process can be simplified.

  In addition, the arrangement of the microlens array formed as the unevenness of the interlayer insulating film 64 may be shifted from the center of the pixel toward the end of the imaging region. That is, by gradually narrowing the interval between adjacent clock wirings 38 from the center of the imaging region toward the end of the imaging region, the center of each microlens array shifts closer to the center of the imaging region toward the end of the imaging region. Formed as follows. By forming the clock wiring 38 and the microlens array in the above-described manner, the optical path difference (difference in the incident angle of light) from the lens (not shown) provided on the top of the CCD image sensor 30 to each microlens. To provide a CCD image sensor having a uniform sensitivity over the entire imaging region, since the difference in the light collection position of the microlens array in the pixel is alleviated, and the difference in sensitivity in each pixel can be reduced. Can do.

  In addition, the microlens array in the present invention is not limited to that provided in each pixel of the solid-state imaging device, and may be provided in each pixel of the display device, for example.

[Second Embodiment]
The present embodiment relates to a CCD image sensor having basically the same structure as the CCD image sensor 30 of the first embodiment, but is different from the first embodiment in a part of the manufacturing method. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and the above description and the drawings are used to simplify the description. The imaging unit 30i of the CCD image sensor 30 in the present embodiment is formed in the same manner as in the first embodiment up to FIG. FIG. 6 is a schematic cross-sectional view of the imaging unit 30i for explaining the process following FIG. 5D in the manufacturing method of the present embodiment. Here, a cross-section along the line BB in FIG. 2 is shown. ing.

  6A shows a state in which an interlayer insulating film 64 is deposited by using, for example, a CVD method on a base obtained by overetching the wiring material film 80 and recessing the grooves 62a and 62b from the interlayer insulating film 62. FIG. Show. In this figure, simply by laminating the interlayer insulating film 64, the surface of the interlayer insulating film 64 in the vicinity of the trenches 62a and 62b does not have a shape that bends smoothly, and an angular step that is relatively similar to the base is formed. It shows a state. Such a cross-sectional shape of the interlayer insulating film 64 can be formed, for example, when the thickness of the interlayer insulating film 64 is thin. The interlayer insulating film 64 cannot efficiently collect the light incident on the regions near the grooves 62a and 62b toward the light receiving pixels. Therefore, after the interlayer insulating film 64 is laminated, the interlayer insulating film 64 is irradiated with gas ions. This gas ion irradiation is performed for the purpose of scraping off the corner 90 of the step of the interlayer insulating film 64. Here, the gas ions are preferably inert gas ions, and argon ions can be used as the inert gas ions, but other inert gas ions may be irradiated. In the irradiation of argon ions to the interlayer insulating film 64, argon ion plasma is generated, and an electric field is applied to the generated plasma to cause the argon ions to collide with the interlayer insulating film 64. At this time, the kinetic energy of argon ions cuts the bonding of the surface atoms or molecules of the interlayer insulating film 64 to allow recombination with other atoms or molecules in the irradiation direction (the surface atoms or molecules are in the groove 62a). , 62b so as to move only in the vicinity of the stepped portion).

  As shown in FIG. 6B, the interlayer insulating film 64 after being irradiated with the argon ions has the corner portions 90 cut off, and the cut-off portions are grooves 62a and 62b in FIG. 6A. It moves to the recessed part of the interlayer insulation film 64 formed in this position. In this way, the curvature of the cross section of the interlayer insulating film 64 is smoothed, and a surface shape in which the light incident on the vicinity of the grooves 62a and 62b is condensed on the light receiving pixels is formed, thereby forming a microlens array. At this time, the portion where the bottom surface 92 of the recess was formed in the grooves 62a and 62b before the gas ion irradiation shown in FIG. 6A becomes a part of the lens-shaped curved surface after the gas ion irradiation. . That is, the outer edge of the lens is enlarged by irradiation with gas ions, and a lens having a wide light receiving surface is formed.

FIG. 2 is a schematic plan view showing a schematic configuration of a frame transfer type CCD image sensor. It is a typical top view showing composition of an image pick-up part of a CCD image sensor of an embodiment. It is typical sectional drawing which shows the structure of the imaging part of the CCD image sensor of embodiment, and is sectional drawing along line segment AA shown in FIG. It is typical sectional drawing which shows the structure of the imaging part of the CCD image sensor of embodiment, and is sectional drawing along line BB shown in FIG. It is typical sectional drawing explaining the manufacturing method which concerns on 1st Embodiment of the imaging part of a CCD image sensor. It is typical sectional drawing explaining the manufacturing method which concerns on 2nd Embodiment of the imaging part of a CCD image sensor. It is typical element sectional drawing explaining the manufacturing method of the micro lens array in the conventional solid-state image sensor.

Explanation of symbols

  30 CCD image sensor, 32 channel region, 34 channel stop region, 36 gate electrode, 38 clock wiring, 40 contact hole, 42 protrusion, 50 semiconductor substrate, 52 p well, 56 insulating layer, 60 gate insulating film, 62, 64 Interlayer insulating film, 68 color filter, 80 wiring material film.

Claims (6)

A plurality of light receiving pixels arranged on one main surface of the semiconductor substrate;
A base light transmitting film laminated on the light receiving pixels;
A pixel separation light shielding member embedded in a groove formed at a position corresponding to the boundary of the light receiving pixels on the surface of the base light transmission film;
A lens forming film that is a light transmission film laminated on the surface of each of the pixel separation light shielding member and the base light transmission film;
Have
The pixel separation light blocking member fills the groove to a height lower than the surface of the base light transmission film;
A solid-state imaging device characterized by the above. The solid-state imaging device according to claim 1,
At least a part of the pixel separating light shielding member constitutes a clock wiring to which a transfer clock for transferring information charges generated in the light receiving pixels is applied;
A solid-state imaging device characterized by the above. The solid-state imaging device according to claim 1,
The plurality of light receiving pixels are arranged in a matrix,
The groove is provided in each of a boundary between the light receiving pixels adjacent in the column direction and a boundary between the light receiving pixels adjacent in the row direction;
A solid-state imaging device characterized by the above. A method of manufacturing a solid-state imaging device having a microlens array corresponding to a plurality of light receiving pixels arranged on one main surface of a semiconductor substrate,
A groove forming step of forming a groove at a position corresponding to the boundary of the light receiving pixel on the surface of the first light transmission film laminated on the light receiving pixel;
Depositing a light shielding film inside the groove and on the surface of the first light transmission film;
Etching back the light shielding film to a partial depth of the groove, and forming a pixel separation light shielding member with the light shielding film selectively left in the groove;
Forming a microlens array by laminating a second light transmission film on the surface of the pixel separation light blocking member and the first light transmission film;
The manufacturing method characterized by having. A method of manufacturing a solid-state imaging device having a microlens array corresponding to a plurality of light receiving pixels arranged on one main surface of a semiconductor substrate,
A groove forming step of forming a groove at a position corresponding to the boundary of the light receiving pixel on the surface of the first light transmission film laminated on the light receiving pixel;
Depositing a light shielding film inside the groove and on the surface of the first light transmission film;
Etching back the light shielding film to a partial depth of the groove, and forming a pixel separation light shielding member with the light shielding film selectively left in the groove;
Laminating a second light transmission film on the surface of the pixel separation light blocking member and the first light transmission film;
Irradiating gas ions toward the second light transmission film to form the microlens array by the second light transmission film;
The manufacturing method characterized by having. A base light-transmitting film laminated on the substrate;
A separation light shielding member embedded in a groove formed at a position surrounding a predetermined region on the surface of the base light transmission film;
A lens forming film that is a light transmission film laminated on the surface of each of the separation light shielding member and the base light transmission film;
Have
The pixel separation light blocking member fills the groove to a height lower than the surface of the base light transmission film;
Lens array characterized by

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