JP2006196746A - Manufacturing method of solid state image sensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a solid state image sensing device which can form a transfer electrode of a single layer without generating short circuit of the transfer electrode and narrowing an opening area of a photosensitive part. <P>SOLUTION: A protection film 20 is formed in advance in a position corresponding to a photosensitive part, and a transfer electrode layer 16a is formed in a region not involving the protection film 20. After a gap 16c is formed in the transfer electrode layer 16a in this state, an insulating film 17 is buried inside the gap 16c. After the protection film 20 is removed, a light screening film 19 covering the transfer electrode 16 is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a solid-state imaging device, and more particularly to a method for manufacturing a solid-state imaging device having a single-layer transfer electrode.

  2. Description of the Related Art In a solid-state imaging device composed of a CCD (Charge Coupled Device), a configuration in which a transfer electrode is formed of two electrode layers is the mainstream. However, it is difficult for a transfer electrode composed of such two electrode layers to sufficiently satisfy the requirements for reduction in resistance and miniaturization of the transfer electrode. Therefore, a transfer electrode is formed by only one electrode layer (see, for example, Patent Documents 1 and 2).

  FIG. 16 is a plan view showing a single-layer transfer electrode in a conventional solid-state imaging device.

  As shown in FIG. 16, in the transfer electrode 16, an opening 16b is formed in the formation region of the light receiving portion 5, and a gap portion 16c is formed between the transfer electrodes 16 adjacent in the transfer direction. Although not shown, an insulating film is embedded in the gap portion 16c in order to ensure a withstand voltage between the adjacent transfer electrodes 16.

  Next, a method for forming the opening 16b and the gap 16c in the transfer electrode 16 will be described with reference to FIG. Note that FIG. 17 shows a plan view of only a region centered on one light receiving portion 5 in FIG. 16 for simplification of description.

  First, as shown in FIG. 17A, after a transfer electrode layer 16a made of, for example, polysilicon is formed on the entire surface of the substrate, a resist pattern (not shown) is formed on the transfer electrode layer 16a, and the resist pattern is masked. As a result, the gap portion 16c is formed by etching the transfer electrode layer 16a. After removing the resist pattern, the insulating film 17 is embedded in the gap portion 16c. As the insulating film 17, a silicon nitride film or a silicon oxide film is used.

  Next, as shown in FIG. 17B, a resist pattern (not shown) is formed on the transfer electrode layer 16a, and the transfer electrode layer 16a is etched using the resist pattern as a mask to form the opening 16b.

  In the manufacturing process described above, the insulating film 17 remains in the region E where the gap 16c and the opening 16b overlap. As a result of the insulating film 17 remaining in the opening 16b, the opening area of the light-shielding film formed on the insulating film 17 is reduced, which causes a problem of sensitivity reduction in a solid-state imaging device miniaturized with high integration.

  It is difficult to remove the insulating film 17 protruding into the opening 16b. The reason is that etching of the transfer electrode layer 16a employs etching having a large etching selection ratio of the transfer electrode layer 16a with respect to the material of the insulating film 17. If the etching conditions with a small etching selection ratio of the transfer electrode layer 16a to the insulating film 17 are adopted, the gate insulating film in the opening 16b is also etched before the insulating film 17 in the region E is completely etched. This is because it causes white wounds.

  Further, in order to prevent the insulating film 17 from protruding into the opening 16b, if the region E where the gap 16c and the opening 16b overlap is set to be small, the opening 16b is moved when the position of the opening 16b is shifted. The transfer electrode layer 16a remains between the gap portion 16c and the gap portion 16c, thereby causing a short circuit.

On the other hand, the unpublished prior application describes a method of simultaneously forming the opening 16b and the gap 16c in the transfer electrode layer 16a (see Patent Document 3).
Japanese Patent Laid-Open No. 4-207076 JP 2003-7997 A Japanese Patent Application No. 2004-170115

  However, in this case, it is necessary to embed an insulating film in the gap 16c with the opening 16b formed. Therefore, when an insulating film is deposited on the entire surface and then an etch-back is performed to leave the insulating film in the gap portion 16c, the insulating film remains on the sidewall of the transfer electrode 16 in the opening 16b (Patent Document). 3 (see FIG. 5).

  If the insulating film remains on the side wall of the transfer electrode 16 in the opening portion 16b, the opening area of the light shielding film formed on the upper layer is reduced in the same manner as described above, and the size is reduced with higher integration. In a solid-state imaging device, a problem of sensitivity reduction occurs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device capable of forming a single-layer transfer electrode without short-circuiting the transfer electrode or reducing the opening area of the light receiving unit. It is to provide a manufacturing method.

  In order to achieve the above object, a method of manufacturing a solid-state imaging device according to the present invention includes a step of forming a protective film in a light receiving portion forming region of a substrate and forming a transfer electrode layer in a region other than the protective film forming region. Removing the transfer electrode layer in a region between the transfer electrodes and separating the transfer electrode layers, embedding an insulating film between the transfer electrodes, removing the protective film, and forming the light receiving portion Forming an opening in the region, and forming a light shielding film covering the transfer electrode and opening the light receiving portion formation region.

In the manufacturing method of the solid-state imaging device of the present invention, since the protective film is formed in the light receiving portion forming region of the substrate in the step of embedding the insulating film between the transfer electrodes, the insulating film is formed only between the transfer electrodes. The insulating film is not left in the light receiving portion forming region. The light receiving portion forming region is a region where the light receiving portion is formed or the light receiving portion is formed later.
After embedding the insulating film, the protective film is removed to form an opening that exposes the light receiving portion formation region, and then a light shielding film that covers the transfer electrode is formed.

  According to the method for manufacturing a solid-state imaging device according to the present invention, a single-layer transfer electrode can be formed without short-circuiting the transfer electrode or reducing the opening area of the light receiving unit.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, an example in which the present invention is applied to an interline transfer type solid-state imaging device will be described.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a solid-state imaging apparatus according to the present embodiment.

  The solid-state imaging device 1 according to the present embodiment includes an imaging unit 2, a horizontal transfer unit 3, and an output unit 4.

  The imaging unit 2 includes a plurality of light receiving units 5 arranged in a matrix and a plurality of vertical transfer units 7 arranged for each vertical column of the light receiving units 5.

  The light receiving unit 5 includes, for example, a photodiode, and photoelectrically converts image light (incident light) incident from a subject into signal charges having a charge amount corresponding to the light amount and accumulates the signal light. The vertical transfer unit 7 is driven by four-phase clock signals φV1, φV2, φV3, and φV4, and transfers signal charges read from the light receiving unit 5 in the vertical direction (downward in the figure). The clock signal is not limited to four phases.

  The horizontal transfer unit 3 is driven by the two-phase clock signals φH1 and φH2, and transfers the signal charges vertically transferred from the vertical transfer unit 7 in the horizontal direction (left direction in the figure).

  The vertical transfer unit 7 and the horizontal transfer unit 3 include a transfer channel region formed in the substrate and extending in the transfer direction, and a plurality of transfer electrodes formed side by side in the transfer direction with an insulating film interposed on the transfer channel region. And have.

  When a voltage is applied to the transfer electrode, a potential well is formed in the transfer channel region. The clock signal for forming this potential well is applied to each transfer electrode arranged in the transfer direction with a phase shift, so that the distribution of the potential well changes sequentially, and the charge in the potential well is transferred. It is transferred along the direction.

  The output unit 4 includes, for example, a charge-voltage conversion unit 4a configured by floating diffusion, converts the signal charge horizontally transferred by the horizontal transfer unit 3 into an electric signal, and outputs the signal as an analog image signal.

  FIG. 2 is a plan view of the main part of the imaging unit 2 in FIG. In FIG. 2, the configuration of the light shielding film and the upper layer thereof is omitted.

  In the vertical transfer unit 7, a plurality of transfer electrodes 16 are arranged in the vertical direction. As shown in FIG. 2, the transfer electrodes 16 arranged in the vertical direction do not overlap each other and have a single-layer transfer electrode structure. A transfer channel region 12 extending in the vertical direction is formed below the transfer electrode 16 arranged in the vertical direction. A gap 16c is provided between the transfer electrodes 16, and the transfer electrodes 16 are separated in the vertical direction. The transfer electrodes 16 in the horizontal direction are connected to each other.

  An opening 16 b is formed in the transfer electrode 16 at a position corresponding to the light receiving unit 5. As will be described later, a light shielding film covering the transfer electrode 16 is formed on the upper layer of the transfer electrode 16, and an opening is also formed in this light shielding film. Incident light passes through this opening and enters the light receiving unit 5.

  An insulating film 17 is embedded in the gap portion 16 c of the transfer electrode 16. The insulating film 17 is embedded because the gap portion 16c between the transfer electrodes 16 is narrow and it is necessary to ensure a withstand voltage between the transfer electrodes 16.

  3A is a cross-sectional view taken along line A-A ′ in FIG. 2, and FIG. 3B is a cross-sectional view taken along line B-B ′ in FIG. 2.

  A charge storage region 11 constituting the light receiving portion 5 is formed in a p-type well formed in a semiconductor substrate made of n-type silicon or a semiconductor substrate made of p-type silicon (hereinafter referred to as substrate 10). . The charge storage region 11 is an n-type semiconductor region, for example. A photodiode is formed between the n-type charge storage region 11 and the p-type region of the substrate 10. Although not shown, a thin p-type semiconductor region is formed on the surface of the charge storage region 11 as a positive charge storage region.

  A transfer channel region 12 made of an n-type semiconductor region is formed on both sides of the charge storage region 11. A read gate region 13 made of a p-type semiconductor region is formed between the charge storage region 11 and the transfer channel region 12 on one side (left side in the figure). The signal charge accumulated in the charge accumulation region 11 is read out to the transfer channel region 12 via the read gate region 13.

  A channel stop region 14 made of a high-concentration p-type semiconductor region is formed between the charge storage region 11 and the transfer channel region 12 on the other side (right side in the drawing). The channel stop region 14 is provided to prevent signal charges from flowing in and out.

  A gate insulating film 15 made of, for example, a silicon oxide film is formed on the substrate 10. Note that the gate insulating film 15 may be formed of a stacked film of a silicon oxide film, a silicon nitride film, and a silicon oxide film, a so-called ONO film.

  A transfer electrode 16 is formed on the transfer channel region 12 and the read gate region 13 via a gate insulating film 15. The transfer electrode 16 is made of, for example, polysilicon. An opening 16 b is formed in the transfer electrode 16 at a position corresponding to the light receiving unit 5. Further, a gap portion 16c is formed between the transfer electrodes 16 in the vertical direction (see FIG. 3B).

  An insulating film 17 is embedded in the gap portion 16 c of the transfer electrode 16. In the present embodiment, a silicon oxide film 17 a and a silicon nitride film 17 b are embedded as the insulating film 17. The insulating film 17 may be a single layer of the silicon oxide film 17a.

  An insulating film 18 made of, for example, a silicon oxide film is formed on the transfer electrode 16. A light shielding film 19 that covers the transfer electrode 16 is formed on the insulating film 18. The light shielding film 19 is made of, for example, aluminum or tungsten. An opening 19 a is formed in the light shielding film 19 at a position corresponding to the light receiving unit 5.

  Although not shown, a passivation film is formed on the light shielding film 19 so as to cover the entire surface, and a planarization film is formed on the passivation film. The passivation film is formed by, for example, plasma SiN, and the planarization film is formed by, for example, UVSiN. A color filter is formed on the planarizing film, and an on-chip lens is formed on the color filter at a position corresponding to the light receiving unit 5.

  Next, an example of a method for manufacturing the solid-state imaging device according to the present embodiment will be described with reference to FIGS. 4 to 9 and FIG. 11, (a) in each drawing is a process sectional view corresponding to FIG. 3 (a), and (b) in each drawing is a sectional view corresponding to FIG. 3 (b). . FIG. 10 is a plan view during the manufacturing process.

  First, as shown in FIGS. 4A and 4B, an n-type impurity or a p-type impurity is ion-implanted into the substrate 10 to thereby form a charge storage region 11, a transfer channel region 12, a read gate region 13, A channel stop region 14 is formed. At this stage, the charge accumulation region 11 may not be formed. Subsequently, a gate insulating film 15 made of a silicon oxide film is formed on the surface of the substrate 10 by thermal oxidation.

  Subsequently, a protective film 20 is formed at a position corresponding to the charge storage region 11 on the gate insulating film 15. If the charge storage region 11 has not yet been formed, the protective film 20 is formed at a position where the charge storage region 11 will be formed later. The protective film 20 is formed by depositing an insulating film on the entire surface of the gate insulating film 15, forming a resist pattern on the insulating film, and performing etching using the resist pattern as a mask. As the protective film 20, for example, a silicon oxide film (BPSG film) to which boron (B) and phosphorus (P) are added, a silicon oxide film (PSG film) to which phosphorus (P) is added, and boron (B) are added. A silicon oxide film (TEOS film) formed using the silicon oxide film (BSG film) and TEOS (tetraethylorthosilicate) as raw materials is used.

  Next, as shown in FIGS. 5A and 5B, a transfer electrode layer 16 a made of, for example, polysilicon is formed on the gate insulating film 15 so as to cover the protective film 20.

  Next, as shown in FIGS. 6A and 6B, the transfer electrode layer 16a on the protective film 20 is removed and planarized. As a result, a flat surface is formed in which the upper surface of the protective film 20 and the upper surface of the transfer electrode layer 16a substantially coincide with each other. The transfer electrode layer 16a on the protective film 20 is removed by, for example, etch back using a photoresist as a mask or CMP (chemical mechanical polishing). When etch back is used, the photoresist is removed by ashing or chemical treatment after the etch back.

  Next, as shown in FIGS. 7A and 7B, a resist pattern (not shown) is formed on the transfer electrode layer 16a, and a position corresponding to the gap 16c is formed by dry etching using the resist pattern as a mask. The transfer electrode layer 16a is removed. Thereafter, the resist pattern is removed. Thereby, the transfer electrode layer 16 a is separated into the transfer electrodes 16.

  Next, as shown in FIGS. 8A and 8B, a silicon oxide film 17a and a silicon nitride film 17b are formed on the transfer electrode 16 and the protective film 20 so as to fill the gap 16c of the transfer electrode 16. Are sequentially deposited to form an insulating film 17.

  Next, as shown in FIGS. 9A and 9B, the transfer electrode 16 other than the gap portion 16c and the unnecessary insulating film 17 on the protective film 20 are removed by an etch back method. As a result, the insulating film 17 remains only in the gap portion 16c.

  Through the above steps, a plan view as shown in FIG. 10 is obtained. As shown in FIG. 10, an insulating film 17 is embedded in the gap portion 16 c of the transfer electrode 16, and a protective film 20 is formed at a position corresponding to the light receiving portion 5.

  Next, as shown in FIGS. 11A and 11B, the protective film 20 is selectively removed by chemical treatment to form an opening 16 b that exposes the light receiving portion 5 to the transfer electrode 16. Here, it is necessary to selectively remove the protective film 20 from the silicon oxide film 17 a constituting the insulating film 17 and the silicon oxide film as the gate insulating film 15. Here, when the silicon oxide film 17a and the gate insulating film 15 are thermal oxide films formed by a thermal oxidation method, and the above oxide film is employed as the protective film 20, the protective film 20 has an etching selectivity of 100 or more. Can be removed. After going through this process, a plan view as shown in FIG. 2 is obtained.

  As a subsequent process, an insulating film 18 made of, for example, silicon oxide is formed on the transfer electrode 16. If the charge storage region 11 to be the light-receiving portion 5 has not yet been formed, impurities are ion-implanted using the transfer electrode 16 as a mask before forming the light-shielding film described later, thereby forming the charge storage region 11. Form.

  Subsequently, a light shielding film material is deposited on the entire surface, and the light shielding film material on the light receiving portion 5 is removed, whereby the light shielding film 19 having the opening 19a and covering the transfer electrode 16 is formed. Further, after forming a passivation film and a planarizing film on the entire surface, a color filter is formed on the planarizing film, and an on-chip lens is formed on the color filter at a position corresponding to each light receiving portion 5.

  As described above, the solid-state imaging device according to this embodiment is manufactured.

  In the manufacturing method of the solid-state imaging device according to the above-described embodiment, the protective film 20 is formed in advance at a position corresponding to the light receiving unit, and the transfer electrode layer 16a is formed in a region other than the protective film 20. In this state, after forming the gap portion 16c, the insulating film 17 is embedded in the gap portion 16c.

  Further, when the insulating film 17 is embedded in the gap portion 16c, the opening portion 16b of the transfer electrode 16 is embedded by the protective film 20, so that the insulating film 17 is not formed in the opening portion 16b. For this reason, the opening area of the light receiving part 5 (the area of the opening part 19a of the light shielding film 19) is not reduced.

  Since the insulating film 17 is not formed in the opening 16b, a resist pattern that secures an overlapping region with the opening 16b can be used when forming the gap 16c. For this reason, the gap part 16c which isolate | separates between the transfer electrodes 16 can be formed reliably, and generation | occurrence | production of the short circuit between the transfer electrodes 16 can be prevented.

  As described above, a single-layer transfer electrode can be formed without short-circuiting the transfer electrode 16 or reducing the opening area of the light-receiving portion 5. For this reason, the problem of sensitivity reduction can be solved particularly in a highly integrated and miniaturized solid-state imaging device.

  The solid-state imaging device is used for a camera such as a video camera, a digital still camera, or an electronic endoscope camera, for example.

  FIG. 12 is a schematic configuration diagram of a camera in which the above-described solid-state imaging device is used.

  The camera 100 includes a solid-state imaging device (CCD) 1, an optical system 102, a drive circuit 103, and a signal processing circuit 104.

  The optical system 102 forms image light (incident light) from the subject on the imaging surface of the solid-state imaging device 1. As a result, each light receiving portion 5 of the solid-state imaging device 1 is converted into a signal charge corresponding to the amount of incident light, and the signal charge is accumulated in the charge accumulation region 11 of the light receiving portion 5 for a certain period.

  The drive circuit 103 supplies various timing signals such as the above-described four-phase clock signals φV1, φV2, φV3, φV4 and two-phase clock signals φH1, φH2 to the solid-state imaging device 1. As a result, various types of driving such as signal charge readout, vertical transfer, and horizontal transfer of the solid-state imaging device 1 are performed. Further, by this driving, an analog image signal is output from the output unit 4 of the solid-state imaging device 1.

  The signal processing circuit 104 performs various kinds of signal processing such as noise removal or conversion into a digital signal on the analog image signal output from the solid-state imaging device 1. After the signal processing by the signal processing circuit 104 is performed, it is stored in a storage medium such as a memory.

  As described above, in the camera 100 such as a video camera or a digital still camera, the image quality of the camera 100 can be improved by using the solid-state imaging device 1 in which the decrease in sensitivity is suppressed even when the pixel size is small. .

(Second Embodiment)
In the first embodiment, the transfer electrode layer 16a is deposited after forming the protective film 20, but in this embodiment, the protective film 20 is formed after depositing the transfer electrode layer 16a.

  13 to 15 are process cross-sectional views for explaining the method for manufacturing the solid-state imaging device according to this embodiment. In addition, (a) of each figure is process sectional drawing equivalent to Fig.3 (a), (b) of each figure is sectional drawing equivalent to FIG.3 (b).

  First, as shown in FIGS. 13A and 13B, by implanting n-type impurities or p-type impurities into the substrate 10, the charge accumulation region 11, the transfer channel region 12, the read gate region 13, the channel stop Region 14 is formed. At this stage, the charge accumulation region 11 may not be formed. Subsequently, a gate insulating film 15 made of a silicon oxide film is formed on the surface of the substrate 10 by thermal oxidation.

  Subsequently, a transfer electrode layer 16 a made of, for example, polysilicon is formed on the entire surface of the gate insulating film 15. Further, a resist pattern having an opening at a position corresponding to the light receiving portion 5 is formed on the transfer electrode layer 16a, and the opening 16b is formed in the transfer electrode layer 16a by etching using the resist pattern as a mask. Thereafter, the resist pattern is removed.

  Next, as shown in FIGS. 14A and 14B, a protective film 20 is deposited on the transfer electrode layer 16a so as to fill the opening 16b. As the protective film 20, the material described in the first embodiment is used. Subsequently, a resist pattern 21 is formed on the protective film 20 at a position corresponding to the light receiving unit 5. If the charge storage region 11 constituting the light receiving unit 5 has not yet been formed, the protective film 20 is formed at a position where the charge storage region 11 is formed later.

  Next, as shown in FIGS. 15A and 15B, the protective film 20 is etched using the resist pattern 21 as a mask to leave the protective film 20 at a position corresponding to the light receiving portion 5. Here, the protective film 20 is left so as to overlap the transfer electrode layer 16a in consideration of the shift of the resist pattern 21.

  Thereafter, the unnecessary protective film 20 on the transfer electrode layer 16a is removed by CMP. As a result, as shown in FIGS. 6A and 6B, a structure in which the upper surface of the protective film 20 and the upper surface of the transfer electrode layer 16a are planarized is obtained.

  As the subsequent steps, the solid-state imaging device is manufactured through the same steps as in the first embodiment. Also in the present embodiment, when the charge accumulation region 11 to be the light receiving portion 5 is formed after the transfer electrode 16, impurities are ion-implanted using the transfer electrode 16 as a mask before the light shielding film 19 is formed. The charge storage region 11 may be formed.

  14A and 14B, after forming the resist pattern 21, the protective film 20 is etched back to remove the unnecessary protective film 20 on the transfer electrode layer 16a. The protective film 20 can be left only in the opening 16b.

  In the manufacturing method of the solid-state imaging device according to the present embodiment described above, after the transfer electrode layer 16a is formed, the opening 16b is formed in the transfer electrode layer 16a, and the protective film 20 is embedded in the opening 16b. In such a state, the gap portion 16c is formed, and the insulating film 17 is embedded in the gap portion 16c.

  Further, when the insulating film 17 is embedded in the gap portion 16c, the opening portion 16b of the transfer electrode 16 is embedded by the protective film 20, so that the insulating film 17 is not formed in the opening portion 16b. For this reason, the opening area of the light receiving part 5 (the area of the opening part 19a of the light shielding film 19) is not reduced.

  Since the insulating film 17 is not formed in the opening 16b, a resist pattern that secures an overlapping region with the opening 16b can be used when forming the gap 16c. For this reason, the gap part 16c which isolate | separates between the transfer electrodes 16 can be formed reliably, and generation | occurrence | production of the short circuit between the transfer electrodes 16 can be prevented.

  As described above, a single-layer transfer electrode can be formed without short-circuiting the transfer electrode 16 or reducing the opening area of the light-receiving portion 5. For this reason, the problem of sensitivity reduction can be solved particularly in a highly integrated and miniaturized solid-state imaging device.

The present invention is not limited to the description of the above embodiment.
For example, the solid-state imaging device of the present invention can also be applied to a frame interline transfer type solid-state imaging device. The insulating film 17 may be a single layer insulating film. In this case, as the insulating film 17, for example, an HTO (High Temperature Oxide) film or a silicon oxide film formed by an HDP (High Density Plasma) method is used.
In addition, various modifications can be made without departing from the scope of the present invention.

It is a schematic block diagram which shows an example of the solid-state imaging device concerning this embodiment. It is a top view of the imaging part of the solid-state imaging device concerning this embodiment. (A) is sectional drawing in the A-A 'line of FIG. 2, (b) is sectional drawing in the B-B' line of FIG. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is a top view in the manufacturing process of the solid-state imaging device concerning this embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of the camera with which the solid-state imaging device which concerns on this embodiment is applied. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment. It is process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on 2nd Embodiment. It is a top view of the solid-state imaging device which has the transfer electrode of the single layer structure of a prior art example. It is a figure which shows the formation method of the transfer electrode of the single layer structure of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solid-state imaging device, 2 ... Imaging part, 3 ... Horizontal transfer part, 4 ... Output part, 4a ... Charge-voltage conversion part, 5 ... Light-receiving part, 7 ... Vertical transfer part, 10 ... Substrate, 11 ... Charge storage area , 12 ... transfer channel region, 13 ... read gate region, 14 ... channel stop region, 15 ... gate insulating film, 16 ... transfer electrode, 16a ... transfer electrode layer, 16b ... opening, 16c ... gap part, 17 ... insulating film 17a ... silicon oxide film, 17b ... silicon nitride film, 18 ... insulating film, 19 ... light shielding film, 19a ... opening, 20 ... protective film, 21 ... resist pattern, 100 ... camera, 102 ... optical system, 103 ... drive Circuit 104 ... Signal processing circuit

Claims (7)

Forming a protective film in a light receiving portion forming region of the substrate, and forming a transfer electrode layer in a region other than the protective film forming region;
Removing the transfer electrode layer in a region between the transfer electrodes and separating each transfer electrode;
Embedding an insulating film between the transfer electrodes;
Removing the protective film to form an opening exposing the light receiving portion forming region; and
Forming a light-shielding film that covers the transfer electrode. The steps of forming the protective film and forming the transfer electrode layer include:
Forming the protective film in a light receiving portion forming region of the substrate;
Forming the transfer electrode layer on the substrate so as to cover the protective film;
The method for manufacturing a solid-state imaging device according to claim 1, further comprising: removing the transfer electrode layer on the protective film. The steps of forming the protective film and forming the transfer electrode layer include:
Forming the transfer electrode layer on the substrate;
Removing the transfer electrode layer in the light receiving formation region of the substrate;
The method of manufacturing a solid-state imaging device according to claim 1, further comprising: forming a protective film in the light receiving formation region of the substrate. The method for manufacturing a solid-state imaging device according to claim 1, wherein in the step of forming the protective film and forming the transfer electrode layer, substantially the same flat surface is formed on the upper surface of the protective film and the upper surface of the transfer electrode. The step of embedding an insulating film between the transfer electrodes includes:
Forming the insulating film on the transfer electrode and the protective film so as to embed between the transfer electrodes;
The method of manufacturing a solid-state imaging device according to claim 1, further comprising: etching back the insulating film to remove the insulating film on the transfer electrode and the protective film. The solid-state imaging device according to claim 1, further comprising a step of forming a light receiving portion by introducing impurities into the substrate in the light receiving portion forming region before the step of forming the protective film and forming the transfer electrode layer. Manufacturing method. The method of manufacturing a solid-state imaging device according to claim 1, further comprising a step of forming a light receiving portion by introducing impurities into the substrate in the light receiving portion forming region using the transfer electrode as a mask after the step of forming the transfer electrode. .

Images