JP2005333038A - Manufacturing method of solid state imaging device, and manufacturing method of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease dark current generated in a solid state imaging device and a generation of flake in such a way that a stress generated in a substrate is made to be dispersed by forming a sidewall in an oxidation mask used in a thermal oxidation process when forming groove in the substrate. <P>SOLUTION: The manufacturing method of the solid state imaging device prepares a photoelectric device converting incident light in photoelectric effect. A readout gate reads a signal charge. A perpendicular charge transmission transmits the signal charge read out in a semiconductor substrate, and forms the readout gate portion and the perpendicular charge transmission portion in a groove prepared in the semiconductor substrate. A forming process of the groove comprises the processes of forming an oxidation mask 15 in a semiconductor 11 front surface on a region in which a photoelectric device portion is formed, forming a sidewall 17 in a side wall of the oxidation mask 15, forming an oxidation film 18 by oxidizing the semiconductor substrate 11 of a region not covered by the oxidation mask 15 and the sidewall 17, and removing the oxidation 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a solid-state imaging device and a method for manufacturing a substrate, which can easily form a groove in which the generation of stress is reduced.

  By forming a groove in the substrate and forming a channel facing the transfer electrode for transferring the charge from the photodiode to the vertical transfer unit and the transfer electrode for transferring the charge, the read voltage can be reduced. There is disclosed a solid-state image pickup device in which a control margin is expanded (see, for example, Patent Document 1). As a technique for forming a groove in a substrate, a technique is known in which a groove is formed in a substrate by removing the LOCOS oxide film after LOCOS oxidation.

  For example, as illustrated in FIG. 4, there is a structure in which a groove 112 is formed in a substrate 111 and the charge transfer performance between the sensor 121 and the vertical transfer unit 122 (read gate unit) is improved by using the groove 112. The manufacturing method of the substrate structure will be described with reference to the manufacturing process diagram of FIG.

  As shown in FIG. 5A, after a 5 nm to 10 nm thermal oxide film 212 is formed on a silicon substrate 211, a silicon nitride film 213 is formed to a thickness of 150 nm to 200 nm by a CVD method. Next, the photoresist film coated and formed by the coating technique is patterned by using a lithography technique to form a resist pattern 214 on the silicon nitride film 213.

Next, as shown in FIG. 5B, the silicon nitride film 213 and the thermal oxide film 212 are processed using a reactive ion etching processing technique. After the processing, the photoresist on the silicon nitride film 213 after the above processing is obtained by an ashing processing using oxygen (O ₂ ) gas and a wet processing mainly containing sulfuric acid / hydrogen peroxide (see FIG. 5 (1)). Remove.

  Next, as shown in FIG. 5C, a silicon oxide layer 215 is formed by thermally oxidizing (LOCOS oxidation) a portion of the silicon substrate 211 not covered with the silicon nitride film 213. At this time, thermal stress generated by thermal oxidation is generated in the silicon substrate 211. In particular, a stress concentration portion 211S is formed in the silicon substrate 211 on the end face of the silicon nitride film 213, and crystal defects are generated. Due to crystal defects that are expected to be caused by the stress at the time of LOCOS oxidation, in the solid-state imaging device using the substrate in which the groove is formed, an increase in dark current and white spot is a problem.

JP-A-11-97666

  The problem to be solved is that the oxide film is formed on the substrate used for the solid-state imaging device by using the LOCOS oxidation method, and the groove is formed by removing the oxide film. The stress concentration and the generation of crystal defects cannot be prevented. The above problem is not limited to a substrate used in a solid-state imaging device, but is a general problem of forming a groove by forming an oxide film on a semiconductor substrate using a LOCOS oxidation method and removing the oxide film.

The manufacturing method of the solid-state imaging device of the present invention includes a photoelectric conversion unit that photoelectrically converts incident light, a read gate unit that reads signal charges from the photoelectric conversion unit, and transfer of the signal charges read by the read gate unit. A solid-state imaging device manufacturing method, wherein the readout gate unit and the vertical charge transfer unit are formed in a groove provided in the semiconductor substrate, wherein the step of forming the groove is provided. Forming an oxidation mask on the surface of the semiconductor substrate on the region where the photoelectric conversion part is to be formed, forming a sidewall on the sidewall of the oxidation mask, and the region not covered with the oxidation mask. A method for manufacturing a solid-state imaging device, comprising: a step of oxidizing a semiconductor substrate to form an oxide film; and a step of removing the oxide film.
This is the main feature.

  The substrate manufacturing method of the present invention includes a step of forming an oxidation mask on a surface of a semiconductor substrate, a step of forming a sidewall on a sidewall of the oxidation mask, and oxidizing the semiconductor substrate that is not covered with the oxidation mask. The main feature is that it includes a step of forming an oxide film and a step of removing the oxide film to form a groove in the semiconductor substrate.

  In the solid-state imaging device manufacturing method and the substrate manufacturing method of the present invention, the sidewall is formed on the side wall of the oxidation mask. If formed, the side walls are also oxidized, so that there is an advantage that concentration of stress on the semiconductor substrate at the end of the oxide film generated at that time can be prevented. Furthermore, since the sidewall is formed, the oxide film formed on the semiconductor substrate is formed so as to be embedded in the lower portion of the sidewall, but does not reach the lower portion of the oxidation mask. For this reason, no stress is generated in the direction of the semiconductor substrate due to the oxidation mask, so that stress concentration due to the formation of the oxide film on the semiconductor substrate does not occur, and therefore no crystal defects occur. Even when the sidewall is formed of an oxide film, oxygen diffuses in the oxide film, so that oxidation in the lower direction of the oxidation mask can be suppressed. It is possible to prevent the stress from being generated.

  This makes it difficult for crystal defects to occur in the semiconductor substrate. Therefore, when the semiconductor substrate is used as the substrate of the solid-state imaging device, dark current and white spot generation in the solid-state imaging device can be reduced. In addition, since the sacrificial oxide film is formed, the semiconductor substrate is not damaged when the oxide mask is processed. Therefore, when a solid-state image pickup device is formed using the substrate, dark current and white spots of the solid-state image pickup device are generated. Can be further reduced.

  The purpose of reducing the occurrence of dark current and white spots, which has occurred in the solid-state imaging device, is to form a groove that forms the charge readout portion and the charge transfer portion groove on the substrate while suppressing the occurrence of crystal defects. This was realized by forming sidewalls on the oxidation mask used in the thermal oxidation process when forming grooves in the substrate and dispersing the stress generated on the substrate.

  A first embodiment relating to a method of manufacturing a solid-state imaging device and a method of manufacturing a substrate according to the present invention will be described with reference to the manufacturing process sectional view of FIG.

As shown in FIG. 1A, a sacrificial oxide film 12 is formed on the surface of the semiconductor substrate 11. For example, a silicon substrate is used as the semiconductor substrate 11, and the sacrificial oxide film 12 is formed of a thermal oxide film as an example, and has a thickness of 5 nm to 10 nm. By forming the sacrificial oxide film 12 in this way, etching damage that enters the semiconductor substrate 11 when an oxide mask is subsequently formed is mitigated. Next, a silicon nitride film, for example, is formed on the sacrificial oxide film 12 as the oxidation mask formation film 13. This silicon nitride film is formed to a thickness of, for example, 150 nm to 200 nm by, for example, a thermal CVD method. As an example of the film forming conditions, a mixed gas of dichlorosilane (SiH ₂ Cl ₂ ), ammonia (NH ₃ ), and nitrogen (N ₂ ) is used as a raw material gas, and each supply flow rate is 50 cm ³ / min, 200 cm ³ / min, 200 cm ³ / min (both are standard conditions), the pressure of the film formation atmosphere is set to 70 Pa, the substrate temperature is set to 760 ° C., and then a photoresist film is applied and formed by a coating technique. Patterning is performed using a technique, and a resist pattern 14 is formed on the oxidation mask forming film 13.

Next, as shown in FIG. 1B, the silicon nitride film is processed by reactive ion etching (RIE) processing using the resist mask 14 to form an oxide mask 15. At this time, it is important to ensure an etching selectivity with respect to the sacrificial oxide film 12 made of silicon oxide so that ions during processing of the silicon nitride film do not enter the semiconductor substrate 11. The sacrificial oxide film 12 made of silicon oxide is also used as a stopper film when processing the subsequent sidewalls. As an example of the silicon nitride processing conditions at this time, a two-frequency parallel plate RIE processing apparatus is used, and a mixed gas of difluoromethane (CH ₂ F ₂ ), oxygen (O ₂ ), and argon (Ar) is used as an etching gas. The respective supply flow rates are set to 40 cm ³ / min, 30 cm ³ / min, and 200 cm ³ / min (all are standard conditions), the pressure of the etching atmosphere is 4.0 Pa, the source power is 1000 W, the bias power is 300 W, the substrate The temperature was set to 40 ° C.

After the etching process, the resist mask 14 on the oxidation mask 15 was removed by, for example, an ashing process using oxygen (O ₂ ) gas and a wet process mainly containing sulfuric acid / hydrogen peroxide as a main component. As an example of the ashing conditions for the resist mask 14, an ICP (Inductively Coupled Plasma) type plasma ashing apparatus is used, oxygen (O ₂ ) gas is used as the ashing gas, and the supply flow rate is 3750 cm ³ / min (standard state). The pressure of the ashing atmosphere was set to 266 Pa, the RF power was set to 1000 W, and the substrate temperature was set to 180 ° C.

Next, as shown in FIG. 1C, a sidewall formation film 16 is formed so as to cover the oxidation mask 15. The sidewall forming film 16 is formed of, for example, a polysilicon film. This polysilicon film thickness is 2/3 or less with respect to the oxidation amount of the silicon substrate because it is necessary to oxidize all the polysilicon film when the subsequent semiconductor substrate (silicon substrate) 11 is oxidized. It is preferable that Here, an example of conditions for forming the sidewall forming film 16 with polysilicon will be described below. As the source gas, a mixed gas of monosilane (SiH ₄ ), helium (He), and nitrogen (N ₂ ) is used, and the supply flow rates are 100 cm ³ / min, 400 cm ³ / min, and 200 cm ³ / min (respectively). Standard condition), the pressure of the film formation atmosphere was set to 70 Pa, and the substrate temperature was set to 610 ° C.

Next, as shown in FIG. 1 (4), the sidewall forming film 16 is entirely etched back by using a reactive ion etching processing technique, so that the sidewall 17 made of polysilicon is formed on the sidewall of the oxide mask 15. Next, as shown in FIG. Form. At the time of the etch back, the sacrificial oxide film 12 made of a silicon oxide film serves as a stopper film, and the semiconductor substrate 11 is not etched. As an example of the above etching processing conditions, an electron cyclotron resonance (ECR) plasma processing apparatus is used as an etching apparatus, and trichlorofluoroethane (C ₂ Cl ₃ F ₃ ) and sulfur hexafluoride (S2) are used as etching gases. SF ₆ ) and a supply flow rate of 60 cm ³ / min and 10 cm ³ / min (respectively, standard conditions), an etching atmosphere pressure of 1.3 Pa, a microwave power of 850 W, and an RF power Was set to 150W. Since the sidewall forming film 16 is formed of polysilicon, the etching when the sidewall 17 is formed is stopped by the sacrificial oxide film 12, and the underlying semiconductor substrate 11 is not damaged by etching. is there. Therefore, the sidewall formation film 16 can also be formed of amorphous silicon having etching selectivity with respect to the sacrificial oxide film 12.

  Next, as shown in FIG. 1 (5), an oxide film 18 is formed on the surface of the semiconductor substrate 11 not covered with the oxide mask 15 by a thermal oxidation method using the oxide mask 15. At this time, the sidewall 17 made of polysilicon is also oxidized simultaneously. In this oxidation, it is necessary to control so that the tip of the oxide film 18 does not extend below the oxidation mask 15. Therefore, the sidewall 17 is formed to have a thickness that is longer than the length of the oxide film 18 that enters under the sidewall 17 when the oxide film 18 is formed. Thus, by forming the sidewall 17 on the side wall of the oxidation mask 15, it is possible to prevent the oxide film 18 from being formed so as to enter below the oxidation mask 15. Generation of stress applied to the substrate 11 can be reduced, and damage such as crystal defects entering the semiconductor substrate 11 in the oxidation process can be suppressed. In the oxidation step, since the end face of the oxide mask 15 is covered with the sidewall 17 made of polysilicon, the semiconductor substrate 11 is gently oxidized from the end of the sidewall 17 to the end of the oxidation mask 15, resulting in a steep volume expansion. The stress generated by being limited can be reduced. Further, since the sidewall 17 is oxidized, it is possible to prevent stress concentration on the semiconductor substrate 11 at the end of the oxide film 18 generated at that time. Therefore, no crystal defects due to the formation of the oxide film 18 on the semiconductor substrate 11 occur.

  Next, the oxidation mask 15 is removed. Since this oxidation mask 15 is formed of a silicon nitride film, it can be etched away by wet treatment with, for example, hot phosphoric acid. Further, since the oxide film 18, the oxidized sidewall 17, and the sacrificial oxide film 12 are made of silicon oxide, they can be etched away by wet treatment using hydrofluoric acid. As a result, as shown in FIG. 1 (6), a groove 19 is formed in the semiconductor substrate 11 where the oxide film 18 [see FIG. 1 (5)] is removed. As described above, the groove 19 was formed in the semiconductor substrate 11.

  Thereafter, the solid-state imaging device 1 is formed using the semiconductor substrate 11. An example of the manufacturing method will be described with reference to the schematic sectional view of FIG.

  As shown in FIG. 2, a gate insulating film 31 of a vertical charge transfer portion and a read gate portion is formed on the surface of the semiconductor substrate 11 including the inner surface of the groove 19 by applying a known solid-state imaging device manufacturing process.

Next, a read gate portion 23 made of a P ⁻ -type layer is formed on the semiconductor substrate 11 at the bottom of the trench 19 by an existing impurity doping technique (for example, ion implantation method). Further, a pixel isolation region 24 made of a P ⁺ type layer is formed. Further, the vertical charge transfer portion 22 is formed by forming the P ⁺ type layer 22p and the N type layer 22n thereon. Further, an N-type layer 21 n that becomes the photoelectric conversion unit 21 is formed on the semiconductor substrate 11. For example, each impurity doping technique is performed by forming a resist mask each time.

  Next, an electrode 32 serving as a charge transfer electrode and a readout electrode is formed on the gate insulating film 31 in the trench 19. The electrode 22 is formed by a technique for forming a transfer electrode of a normal solid-state image sensor. The electrode 32 is formed in, for example, a one-layer structure, a two-layer structure, a three-layer structure, or a four-layer structure. The portion of the electrode 32 formed in the vertical transfer direction is preferably formed on the vertical charge transfer portion 22 and the read gate portion 23 in the groove 19. Alternatively, it may be formed on at least a part of the pixel isolation region 24, on the vertical charge transfer unit 22, and on the read gate unit 23 due to mask misalignment in lithography technique, etching error, or the like. Alternatively, it may be formed on at least part of the pixel isolation region 24, on the vertical charge transfer unit 22, and on part of the readout gate unit 23.

  Next, a hole accumulation layer (hole accumulation layer) 21p is formed on the N-type layer 21n by an impurity doping technique (for example, ion implantation). In this manner, the photoelectric conversion unit 21 including the N-type layer 21n and the hole accumulation layer 21p is formed. At this time, etching damage and crystal defects due to stress during local oxidation are likely to occur in the side wall of the groove 19, so that electrons generated from the location are expected to be noise components. In order to prevent this, it is possible to further reduce the noise component by injecting P-type impurities into the substrate surface side of the side wall portion of the groove 19.

  Next, after forming an interlayer insulating film 33 covering the electrode 32, a light shielding film 34 is formed on the substrate 11 through the interlayer insulating film 33 so as to fill a gap between the groove 19 and the electrode 32. In this way, by embedding all or part of the gap between the groove 19 and the electrode 32 with the light shielding film 34, the light component directly entering the vertical charge transfer unit 22 can be blocked, and the CCD (charge coupling) It is possible to reduce smear, which is one of the noise components of the device. Thereafter, the light-shielding film 34 on the photoelectric conversion unit 21 is processed and opened by the lithography technique and the etching technique.

  In the manufacturing method, it is desirable that the depth of the bottom of the groove 19 and the depth of the junction between the hole accumulation layer 21p and the N-type layer 21n formed in the upper layer of the photoelectric conversion portion 21 are the same. The light shielding film 34 is preferably formed so that a pulse voltage is applied. Alternatively, the light shielding film 34 is preferably formed so that a DC voltage is applied.

  Thereafter, an interlayer insulating film 35 is formed, the surface is planarized, a color filter layer 36 is formed, and an on-chip lens 37 is further formed. In this way, the solid-state imaging device 1 is formed.

  As described above, since the solid-state imaging device 1 is manufactured using the semiconductor substrate 11 in which crystal defects are hardly generated, dark current and white spot generation of the solid-state imaging device 1 can be reduced. In addition, since the sacrificial oxide film is formed, the semiconductor substrate 11 is not damaged when the oxide mask 15 is processed. Therefore, when the solid-state imaging device 1 is formed using the semiconductor substrate 11, Dark current and white spot generation can be further reduced.

In the first embodiment, the sidewall 17 is formed of polysilicon, but it may be formed of other silicon, for example, amorphous silicon.

  The second embodiment of the method for manufacturing a solid-state imaging device according to the present invention is the same as the first embodiment, except that the sidewall 17 is formed of a silicon oxide film. Other configurations are the same as those described in the first embodiment. Even when the sidewalls 17 are formed of silicon oxide in this way, oxygen diffuses into the sidewalls 17 because oxygen diffuses into the oxide film, so that oxidation toward the lower portion of the oxidation mask 15 is suppressed. Can do. Therefore, the generation of stress on the semiconductor substrate 11 by the oxidation mask 15 can be prevented in substantially the same manner as in the first embodiment.

  Next, a third embodiment of the method for manufacturing a solid-state imaging device and the method for manufacturing a substrate according to the present invention will be described with reference to the manufacturing process sectional view of FIG.

  As shown in FIG. 3A, a sacrificial oxide film 12 is formed on the surface of the semiconductor substrate 11 in the same manner as the process described with reference to FIG. For example, a silicon substrate is used as the semiconductor substrate 11, and the sacrificial oxide film 12 is formed of a thermal oxide film as an example, and has a thickness of 5 nm to 10 nm. By forming the sacrificial oxide film 12 in this way, etching damage that enters the semiconductor substrate 11 when an oxide mask is subsequently formed is mitigated. Next, a silicon nitride film, for example, is formed on the sacrificial oxide film 12 as the oxidation mask formation film 13. This silicon nitride film is formed to a thickness of, for example, 150 nm to 200 nm by, for example, a thermal CVD method. Next, after a photoresist film is applied and formed by a coating technique, patterning is performed using a lithography technique to form a resist pattern 14 on the oxidation mask forming film 13.

Next, as shown in FIG. 3B, silicon nitride is formed by reactive ion etching (RIE) processing using a resist mask 14 in the same manner as the process described with reference to FIG. The oxide mask 15 is formed by processing the film. At this time, it is important to secure an etching selectivity with respect to the sacrificial oxide film 12 made of silicon oxide so that ions during processing of the silicon nitride film do not enter the semiconductor substrate 11. After the etching process, the resist mask 14 on the oxidation mask 15 was removed by, for example, an ashing process using oxygen (O ₂ ) gas and a wet process mainly containing sulfuric acid / hydrogen peroxide as a main component.

  Next, as shown in FIG. 3 (3), a sidewall formation film 16 is formed so as to cover the oxidation mask 15 in the same manner as the process described with reference to FIG. 1 (3) of the first embodiment. . The sidewall forming film 16 is formed of, for example, a silicon oxide film.

  Next, as shown in FIG. 3 (4), the side wall forming film 16 is entirely etched using the reactive ion etching processing technique in the same manner as the process described with reference to FIG. 1 (4) of the first embodiment. By performing the back, sidewalls 17 made of polysilicon are formed on the sidewalls of the oxide mask 15. At the time of the etch back, the sacrificial oxide film 12 is also etched, and the semiconductor substrate 11 is exposed.

  Next, as shown in FIG. 3 (5), the semiconductor substrate 11 is etched using the oxidation mask 15 and the sidewalls 17 as masks, thereby forming grooves 41. The depth of the groove 41 is appropriately set depending on the thickness of the oxide film to be formed later. For example, when the oxide film is formed on the semiconductor substrate 11 in the subsequent oxidation step, the depth of the groove 41 is set so that the height of the oxide film surface becomes equal to the surface of the semiconductor substrate 11.

    Next, as shown in FIG. 3 (6), the surface of the semiconductor substrate 11 in the trench 41 is oxidized to form a sacrificial oxide film 42.

  Next, as shown in FIG. 3 (7), the oxide mask 15 is coated by the thermal oxidation method using the oxidation mask 15 in the same manner as the process described in FIG. 1 (5) of the first embodiment. An oxide film 18 is formed on the surface of the semiconductor substrate 11 that has not been formed. In this oxidation, it is necessary to control so that the tip of the oxide film 18 does not extend below the oxidation mask 15. Therefore, the sidewall 17 is formed to have a thickness that is longer than the length of the oxide film 18 that enters under the sidewall 17 when the oxide film 18 is formed. Thus, by forming the sidewall 17 on the side wall of the oxide mask 15, it is possible to prevent the oxide film 18 from being formed so as to enter below the oxide mask 15, and thereby the semiconductor of the oxide mask 15. It is possible to relieve the generation of stress in the direction of the substrate 11 and suppress damage such as crystal defects that enter the semiconductor substrate 11 in the oxidation process. In the oxidation step, since the end face of the oxidation mask 15 is covered with the sidewall 17 made of silicon oxide, oxygen at the time of oxidation is diffused also into the sidewall made of silicon oxide, and is generated at that time. Stress concentration on the semiconductor substrate 11 at the end of the oxide film 18 can be prevented. Therefore, the semiconductor substrate 11 does not generate crystal defects due to the formation of the oxide film 18.

  Next, the oxidation mask 15 is removed. Since this oxidation mask 15 is formed of a silicon nitride film, it can be etched away by wet treatment with, for example, hot phosphoric acid. Further, since the oxide film 18, the oxidized sidewall 17, and the sacrificial oxide film 12 are made of silicon oxide, they can be etched away by wet treatment using hydrofluoric acid. As a result, as shown in FIG. 3 (8), a groove 19 is formed in the semiconductor substrate 11 from which the oxide film 18 [see FIG. 3 (7)] has been removed. As described above, the groove 19 was formed in the semiconductor substrate 11. Etching damage that occurs when the semiconductor substrate 11 is etched is taken into the oxide film 18 by the oxidation step, and the oxide film 18 is removed, so that the etching into the semiconductor substrate 11 exposed in the groove 19 is performed. No damage remains.

  Thereafter, a solid-state imaging device can be manufactured in the same manner as described with reference to the schematic sectional view of FIG.

  In the substrate manufacturing methods described in the above embodiments, when the oxide film 18 formed on the semiconductor substrate 11 is removed to form the groove 19, a mask is formed on a part of the oxide film 18, and the oxide film 18 is formed. It is possible to leave a part of the oxide film 18 at the time of removal. Through such a process, it becomes possible to simultaneously form an element isolation region (or pixel isolation region) made of the oxide film 18 and a groove 19 from which the oxide film 18 has been removed in the semiconductor substrate 11.

  The manufacturing method of the solid-state imaging device and the manufacturing method of the substrate of the present invention are preferably applied to the manufacturing method of the solid-state imaging device, and the manufacturing method of the semiconductor device in which the groove and the oxide film are simultaneously formed on the semiconductor substrate. Is also applicable.

It is manufacturing process sectional drawing which showed 1st Example which concerns on the manufacturing method of the solid-state imaging device of this invention, and the manufacturing method of a board | substrate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating a first embodiment according to a method for manufacturing a solid-state imaging device of the present invention. It is manufacturing process sectional drawing which showed 3rd Example which concerns on the manufacturing method of the solid-state imaging device of this invention, and the manufacturing method of a board | substrate. It is schematic structure sectional drawing which showed the conventional solid-state imaging device. It is manufacturing process sectional drawing which showed the manufacturing method of the conventional solid-state imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solid-state imaging device, 11 ... Semiconductor substrate, 15 ... Oxidation mask, 17 ... Side wall, 18 ... Oxide film, 19 ... Groove, 21 ... Photoelectric conversion part, 22 ... Vertical charge transfer part, 23 ... Read-out gate part

Claims (10)

A semiconductor substrate includes a photoelectric conversion unit that photoelectrically converts incident light, a read gate unit that reads signal charges from the photoelectric conversion unit, and a vertical charge transfer unit that transfers the signal charges read by the read gate unit. Prepared,
A method of manufacturing a solid-state imaging device, wherein the readout gate unit and the vertical charge transfer unit are formed in a groove provided in the semiconductor substrate,
The step of forming the groove includes
Forming an oxidation mask on the surface of the semiconductor substrate on the region where the photoelectric conversion part is formed;
Forming a sidewall on the sidewall of the oxidation mask;
Oxidizing the semiconductor substrate in a region not covered with the oxidation mask to form an oxide film;
And a step of removing the oxide film. A method of manufacturing a solid-state imaging device. The method of manufacturing a solid-state imaging device according to claim 1, wherein the sidewall is formed to have a thickness that is longer than a length of the oxide film that enters below the sidewall when the oxide film is formed. The method for manufacturing a solid-state imaging device according to claim 1, wherein a sacrificial oxide film is formed on the surface of the semiconductor substrate before forming the oxidation mask. The sidewall is made of silicon,
The method for manufacturing a solid-state imaging device according to claim 1, wherein the oxide film is oxidized when the oxide film is formed. The method for manufacturing a solid-state imaging device according to claim 1, wherein the sidewall is made of silicon oxide. Forming an oxidation mask on the surface of the semiconductor substrate;
Forming a sidewall on the sidewall of the oxidation mask;
Oxidizing the semiconductor substrate not covered with the oxidation mask to form an oxide film;
And a step of forming a groove in the semiconductor substrate by removing the oxide film. The method for manufacturing a substrate according to claim 6, wherein the sidewall is formed to have a thickness that is longer than a length of the oxide film that enters under the sidewall when the oxide film is formed. The method of manufacturing a substrate according to claim 6, wherein a sacrificial oxide film is formed on the surface of the semiconductor substrate before forming the oxidation mask. The sidewall is made of silicon,
The substrate manufacturing method according to claim 6, wherein the substrate is oxidized when the oxide film is formed. The substrate manufacturing method according to claim 6, wherein the sidewall is made of silicon oxide.

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