JP5525894B2 - Manufacturing method of solid-state imaging device - Google Patents

Description

  The present invention relates to a method for manufacturing a solid-state imaging device.

  As an image sensor used for a digital still camera, a digital video camera, a mobile phone camera, an endoscope camera, etc., pixels including photodiodes are arranged on a semiconductor substrate such as a silicon (Si) chip, Solid-state imaging devices (so-called CCD sensors and CMOS sensors) that acquire signal charges corresponding to photoelectrons generated in a photodiode with a CCD type or CMOS type readout circuit are widely known.

  In these solid-state imaging devices, not only a photodiode but also a signal readout circuit and a multilayer wiring associated therewith are formed in each pixel on a semiconductor substrate. For this reason, as the pixel miniaturization progresses, the readout circuit / wiring region occupying one pixel becomes relatively wide, and the “light aperture ratio” that the light receiving area of the photodiode is reduced becomes a problem. A decrease in aperture ratio leads to a decrease in sensitivity.

  In view of this, a stacked solid-state imaging device that can improve the aperture ratio by forming a photoelectric conversion layer above a semiconductor substrate on which a readout circuit and wiring are formed has been proposed (see Patent Document 1). A stacked solid-state imaging device includes a pixel electrode formed on a semiconductor substrate, a photoelectric conversion layer formed on the pixel electrode, and a counter electrode formed on the photoelectric conversion layer. A large number are arranged on a plane parallel to the surface. In the photoelectric conversion element, by applying a bias voltage between the pixel electrode and the counter electrode, excitons generated in the photoelectric conversion layer dissociate into electrons and holes, and the electrons moved to the pixel electrode according to the bias voltage Alternatively, a signal corresponding to the charge of the holes is acquired by a CCD type or CMOS type readout circuit provided in the semiconductor substrate.

  A stacked solid-state imaging device sequentially forms a pixel electrode and an organic film functioning as a photoelectric conversion layer by vapor-depositing an organic material on a semiconductor substrate on which a readout circuit is formed. A pixel electrode made of a transparent electrode is formed. Further, it is manufactured by sequentially laminating a sealing film, a color filter and the like on the pixel electrode.

JP 2008-72090 A

  Incidentally, in the process of manufacturing the solid-state imaging device, fine particles (hereinafter referred to as particles) made of iron or other metal may adhere to the surface of the organic film. If a sealing film is formed with particles adhering to the surface of the organic film, white defects will occur in the pixel area where the particles have adhered when an image captured by the manufactured solid-state image sensor is displayed. Resulting in.

  The present invention provides a method for manufacturing a solid-state imaging device capable of suppressing the occurrence of white defect.

A method for manufacturing a solid-state imaging device, comprising: a substrate; an organic film provided on the substrate; and a pixel region that generates a charge in response to light incident on the organic film, wherein the light incident side surface of the substrate And depositing the organic film on the surface of the organic film by exposing the deposited organic film to a magnetic field after the deposition process and before forming another film on the organic film. A method of manufacturing a solid-state imaging device, comprising: a metal removal step of removing the attached metal .

  According to this method, by depositing the organic film and then exposing it to a magnetic field, the particles attached to the organic film can be separated from the surface of the organic film by magnetic force. Then, by forming the counter electrode and the sealing film on the organic film, it is possible to suppress the occurrence of white defect caused by particles in the pixel portion of the manufactured solid-state imaging device.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the solid-state image sensor which can suppress generation | occurrence | production of a white-scratch defect can be provided.

It is a cross-sectional schematic diagram which shows the structure of a solid-state image sensor. It is a figure which shows the procedure of the manufacture process of a solid-state image sensor. It is a figure which shows the procedure of the manufacture process of a solid-state image sensor. It is a figure which shows the procedure of the manufacture process of a solid-state image sensor. It is a figure which shows the procedure of the manufacture process of a solid-state image sensor.

  First, a configuration example of a solid-state image sensor will be described.

FIG. 1 is a schematic cross-sectional view showing the configuration of a stacked solid-state imaging device.
A solid-state imaging device 100 illustrated in FIG. 1 includes a substrate 101, an insulating layer 102, a connection electrode 103, a pixel electrode 104, a connection portion 105, a connection portion 106, an organic film 107, a counter electrode 108, and a buffer. A layer 109, a sealing film 110, a color filter 111, a partition 112, a light shielding layer 113, a protective layer 114, a counter electrode voltage supply unit 115, and a readout circuit 116 are provided.

  The substrate 101 is a glass substrate or a semiconductor substrate such as Si. An insulating layer 102 is formed on the substrate 101. A plurality of pixel electrodes 104 and a plurality of connection electrodes 103 are formed on the surface of the insulating layer 102.

  The organic film 107 includes at least a photoelectric conversion layer. The photoelectric conversion layer generates an electric charge according to the received light. The organic film 107 is provided on the plurality of pixel electrodes 104 so as to cover them. The organic film 107 has a constant film thickness on the pixel electrode 104, but there is no problem even if the film thickness changes outside the pixel portion (outside the effective pixel area). Details of the organic film 107 will be described later. Note that the organic film 107 includes not only a layer formed of only an organic material but also a layer in which a part of the layer includes an inorganic material.

  The counter electrode 108 is an electrode facing the pixel electrode 104, and is provided on the organic film 107 so as to cover it. The counter electrode 108 is made of a conductive material that is transparent to incident light so that light enters the organic film 107. The counter electrode 108 is formed up to the connection electrode 103 disposed outside the organic film 107 and is electrically connected to the connection electrode 103.

  The connection part 106 is embedded in the insulating layer 102 and is a plug or the like for electrically connecting the connection electrode 103 and the counter electrode voltage supply part 115. The counter electrode voltage supply unit 115 is formed on the substrate 101 and applies a predetermined voltage to the counter electrode 108 via the connection unit 106 and the connection electrode 103. When the voltage to be applied to the counter electrode 108 is higher than the power supply voltage of the solid-state imaging device 100, the power supply voltage is boosted by a booster circuit such as a charge pump to supply the predetermined voltage.

  The pixel electrode 104 is an electrode for collecting charges for collecting charges generated in the organic film 107 between the pixel electrode 104 and the counter electrode 108 facing the pixel electrode 104. The readout circuit 116 is provided on the substrate 101 corresponding to each of the plurality of pixel electrodes 104, and reads out a signal corresponding to the charge collected by the corresponding pixel electrode 104. The reading circuit 116 is configured by, for example, a CCD, a MOS circuit, or a TFT circuit, and is shielded from light by a light shielding layer (not shown) disposed in the insulating layer 102. Details of the pixel electrode 104 and the readout circuit 116 will be described later.

  The sealing film 110 is formed on the counter electrode 108 so as to cover the counter electrode 108.

  The color filter 111 is formed at a position facing each pixel electrode 104 on the sealing film 110.

  The partition wall 112 is provided between the color filters 111 and is for improving the light transmission efficiency of the color filter 111.

  The light shielding layer 113 is formed in a region other than the region where the color filter 111 and the partition 112 are provided on the sealing film 110, and prevents light from entering the organic film 107 formed outside the effective pixel region.

  The protective layer 114 is formed on the color filter 111, the partition 112, and the light shielding layer 113, and protects the entire solid-state imaging device.

  Details of the sealing film 110, the color filter 111, the partition 112, the light shielding layer 113, and the protective layer 114 will be described later.

  In the example of FIG. 1, the pixel electrode 104 and the connection electrode 103 are embedded in the surface portion of the insulating layer 102, but they may be formed on the insulating layer 102. In addition, although a plurality of sets of the connection electrode 103, the connection unit 106, and the counter electrode voltage supply unit 115 are provided, only one set may be provided. As in the example of FIG. 1, by supplying a voltage from both ends of the counter electrode 108 to the counter electrode 108, a voltage drop at the counter electrode 108 can be suppressed. The number of sets may be increased or decreased as appropriate in consideration of the chip area of the element.

  The solid-state imaging device 100 has a plurality of pixel portions. The plurality of pixel portions are two-dimensionally arranged in a state where the substrate 101 is viewed in plan from the light incident side. The pixel portion includes at least a pixel electrode 104, an organic film 107, a counter electrode 108 facing the pixel electrode 104, a sealing film 110, a color filter 111, and a readout circuit 116.

  Next, a configuration example of the peripheral circuit will be described. The readout circuit 116 described above preferably employs a CCD or CMOS circuit for general image sensor applications. From the viewpoint of noise and high speed, it is preferable to employ a CMOS circuit. The configuration example of the peripheral circuit described below is a configuration example when a CMOS circuit is used as the reading circuit 116.

Next, the procedure of the manufacturing process of the solid-state image sensor will be described based on the drawings. 2 to 5 are schematic cross-sectional views showing the steps of the manufacturing process of the solid-state imaging device.
First, as shown in FIG. 2, the reading circuit 116 and the insulating layer 102 pixel electrode 104 are formed on the substrate 101. After the pixel electrode 104 is formed, the substrate 101 is washed.

  After the cleaning, an organic film 107 is deposited on the pixel electrode 104 of the substrate 101 as shown in FIG. When performing vapor deposition 107, the substrate 101 is disposed so that the surface on which the pixel electrode 104 is formed faces downward and faces the vapor deposition source upward. The organic film 107 is deposited using a mask M that is patterned so as to cover the entire pixel region except for peripheral circuits.

  The mask M is preferably a silicon mask. When a metal mask or the like is used, particles of the metal material constituting the metal mask may adhere to the organic film 107 and become particles. However, when a silicon mask is used, adhesion of particles due to the mask material is avoided. be able to.

  After the organic film 107 is deposited, as shown in FIG. 4, a magnetic field is formed on the surface of the organic film 107 using a magnet MG, and particles are adsorbed to the magnet MG. Thereafter, as shown in FIG. 5, the counter electrode 108 and the sealing film 110 are sequentially formed on the organic film 107. Although not shown, a color filter 111, a partition 112, a light shielding layer 113, a protective layer 114, and the like are formed on the sealing film 110 as shown in FIG.

  As described above, if the particles attached to the surface of the organic film 107 are removed by exposing the organic film 107 to a magnetic field before another film is formed on the deposited organic film 107, the organic film is formed in a later step. It is possible to suppress the occurrence of white defect caused by particles in the pixel portion of the solid-state imaging device manufactured by forming the counter electrode 108 and the sealing film 110 on the 107.

  For example, a permanent magnet can be used as the magnet used for particle removal. Moreover, as long as the deposited organic film 107 can be exposed to a magnetic field, it is not limited to a magnet, For example, a solenoid coil etc. may be used.

  Next, details of the organic film 107, the pixel electrode 104, the counter electrode 108, the sealing film 110, and the color filter 111 will be described.

<Organic film>
The organic film 107 includes a photoelectric conversion layer and a charge blocking layer.

  The charge blocking layer has a function of suppressing dark current. The charge blocking layer may be composed of a plurality of layers, for example, may be composed of a first blocking layer and a second blocking layer. As described above, by forming the charge blocking layer into a plurality of layers, an interface is formed between the first blocking layer and the second blocking layer, and discontinuity occurs in the intermediate level existing in each layer, so that It becomes difficult for the charge carrier to move through the level, and dark current can be suppressed. The charge blocking layer may be a single layer.

  The photoelectric conversion layer includes a p-type organic semiconductor and an n-type organic semiconductor. Exciton dissociation efficiency can be increased by joining a p-type organic semiconductor and an n-type organic semiconductor to form a donor-acceptor interface. For this reason, the photoelectric conversion layer of the structure which joined the p-type organic semiconductor and the n-type organic semiconductor expresses high photoelectric conversion efficiency. In particular, a photoelectric conversion layer in which a p-type organic semiconductor and an n-type organic semiconductor are mixed is preferable because the junction interface is increased and the photoelectric conversion efficiency is improved.

  A p-type organic semiconductor (compound) is a donor organic semiconductor, and is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. Not limited to this, as described above, any organic compound having an ionization potential smaller than that of an organic compound used as an n-type (acceptor) compound may be used as a donor organic semiconductor.

  An n-type organic semiconductor (compound) is an acceptor organic semiconductor, and is mainly represented by an electron-transporting organic compound and refers to an organic compound having a property of easily accepting electrons. More specifically, an n-type organic semiconductor refers to an organic compound having a larger electron affinity when two organic compounds are used in contact with each other. Therefore, any organic compound can be used as the acceptor organic compound as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (E.g. pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, Benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxa Azoles, imidazopyridines, pyralidines, pyrrolopyridines, thiadiazolopyridines, dibenzazepines, tribenzazepines, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds as ligands Etc. Not limited to this, as described above, any organic compound having an electron affinity higher than that of the organic compound used as the p-type (donor) compound may be used as the acceptor organic semiconductor.

  Any organic dye may be used as the p-type organic semiconductor or the n-type organic semiconductor, but preferably a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye (including zero methine merocyanine (simple merocyanine)), 3 Nuclear merocyanine dye, 4-nuclear merocyanine dye, rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye, azamethine dye, coumarin dye, arylidene dye, anthraquinone dye, tri Phenylmethane dye, azo dye, azomethine dye, spiro compound, metallocene dye, fluorenone dye, fulgide dye, perylene dye, perinone dye, phenazine dye, phenothiazine color , Quinone dye, diphenylmethane dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye, quinophthalone dye, phenoxazine dye, phthaloperylene dye, diketopyrrolopyrrole dye, dioxane dye, porphyrin dye, chlorophyll dye, phthalocyanine dye, And metal complex dyes and condensed aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives).

As the n-type organic semiconductor, it is particularly preferable to use fullerene or a fullerene derivative having excellent electron transport properties. The fullerene, fullerene _{C 60,} fullerene _{C 70,} fullerene _{C 76,} fullerene _{C 78,} fullerene _{C 80,} fullerene _{C 82,} fullerene _{C 84,} fullerene _{C 90,} fullerene _{C 96,} fullerene _{C 240,} fullerene _{C 540,} mixed Fullerene and fullerene nanotube are represented, and a fullerene derivative represents a compound having a substituent added thereto.

  The substituent for the fullerene derivative is preferably an alkyl group, an aryl group, or a heterocyclic group. More preferably, the alkyl group is an alkyl group having 1 to 12 carbon atoms, and the aryl group and the heterocyclic group are preferably a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring. , Biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran Ring, benzimidazole ring, imidazopyridine ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring, phenanthroline , Thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, or phenazine ring, more preferably a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, pyridine ring, imidazole ring, oxazole ring, or A thiazole ring, particularly preferably a benzene ring, a naphthalene ring, or a pyridine ring. These may further have a substituent, and the substituents may be bonded as much as possible to form a ring. In addition, you may have a some substituent and they may be the same or different. A plurality of substituents may be combined as much as possible to form a ring.

  When the photoelectric conversion layer contains fullerene or a fullerene derivative, electrons generated by photoelectric conversion can be quickly transported to the pixel electrode 104 or the counter electrode 108 via the fullerene molecule or fullerene derivative molecule. When fullerene molecules or fullerene derivative molecules are connected to form an electron path, the electron transport property is improved, and the high-speed response of the photoelectric conversion element can be realized. For this purpose, it is preferable that 40% or more of fullerene or fullerene derivative is contained in the photoelectric conversion layer. However, when there are too many fullerenes or fullerene derivatives, the p-type organic semiconductor is reduced, the junction interface is reduced, and the exciton dissociation efficiency is lowered.

  When a triarylamine compound described in Japanese Patent No. 4213832 is used as a p-type organic semiconductor mixed with fullerene or a fullerene derivative in a photoelectric conversion layer, a high SN ratio of the photoelectric conversion element can be expressed. preferable. If the ratio of fullerene or fullerene derivative in the photoelectric conversion layer is too large, the amount of the triarylamine compound is reduced and the amount of incident light absorbed is reduced. As a result, the photoelectric conversion efficiency is reduced, so that the fullerene or fullerene derivative contained in the photoelectric conversion layer preferably has a composition of 85% or less.

  An electron donating organic material can be used for the first blocking layer and the second blocking layer. Specifically, in a low molecular material, N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD) or 4,4′-bis [N Aromatic diamine compounds such as-(naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, polyarylalkane, butadiene 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, etc. Polyphyrin compounds, triazole derivatives, oxa Zazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, etc. In the polymer material, a polymer such as phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, diacetylene, or a derivative thereof can be used. Any compound having sufficient hole transportability can be used.

  An inorganic material can also be used as the charge blocking layer. In general, since an inorganic material has a dielectric constant larger than that of an organic material, when used in a charge blocking layer, a large voltage is applied to the photoelectric conversion layer, and the photoelectric conversion efficiency can be increased. Materials that can be a charge blocking layer include calcium oxide, chromium oxide, chromium oxide copper, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, oxide Examples include indium silver and iridium oxide.

  In the charge blocking layer composed of a plurality of layers, the layer adjacent to the photoelectric conversion layer among the plurality of layers is preferably a layer made of the same material as the p-type organic semiconductor contained in the photoelectric conversion layer. In this way, by using the same p-type organic semiconductor for the charge blocking layer, it is possible to suppress the formation of an intermediate level at the interface between the photoelectric conversion layer and the adjacent layer, and to further suppress the dark current. .

  When the charge blocking layer is a single layer, the layer can be a layer made of an inorganic material, or in the case of a plurality of layers, one or more layers can be a layer made of an inorganic material. .

<Pixel electrode>
The pixel electrode 104 collects electron or hole charges generated in the organic film 107 including the photoelectric conversion layer on the pixel electrode 104. The charges collected by each pixel electrode 104 become a signal in the readout circuit 116 of each corresponding pixel, and an image is synthesized from signals acquired from a plurality of pixels.

At the edge of the pixel electrode 104, a step corresponding to the film thickness of the pixel electrode 104 is steep, there are significant irregularities on the surface of the pixel electrode 104, or minute dust adheres to the pixel electrode 104. The organic film 107 on the pixel electrode 104 becomes thinner than a desired film thickness or cracks. When the counter electrode 108 is formed on the organic film 107 in such a state, a pixel defect such as an increase in dark current or a short circuit occurs due to contact between the pixel electrode 104 and the counter electrode 108 in the defective portion or electric field concentration.

  In order to prevent the above defects and improve the reliability of the solid-state imaging device, the surface roughness Ra of the pixel electrode 104 is preferably 0.6 nm or less. The smaller the surface roughness Ra of the pixel electrode 104, the smaller the surface unevenness, and the better the surface flatness. In order to remove particles on the pixel electrode 104, it is particularly preferable to clean the substrate by a general cleaning technique used in a semiconductor manufacturing process before the organic film 107 is formed.

<Counter electrode>
The counter electrode 108 applies an electric field to the organic film 107 by sandwiching the organic film 107 including the photoelectric conversion layer together with the pixel electrode 104, and collects the charges generated in the photoelectric conversion layer at the pixel electrode 104. Collects charges with the opposite polarity to the signal charge. Since the collection of the reverse polarity charge does not need to be divided among the pixels, the counter electrode 108 can be shared by a plurality of pixels. Therefore, it may be called a common electrode (common electrode).

  The counter electrode 108 is preferably formed of a transparent conductive film so that light enters the organic film 107 including the photoelectric conversion layer. For example, a metal, a metal oxide, a metal nitride, a metal boride, or an organic conductive material is used. Examples thereof include compounds and mixtures thereof. Specific examples include tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), conductive metal oxides such as titanium oxide, and metal nitrides such as TiN. Metal, gold (Au), platinum (Pt), silver (Ag), chromium (Cr), nickel (Ni), aluminum (Al), etc., and a mixture or laminate of these metals and conductive metal oxides Products, organic conductive compounds such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO. Particularly preferable materials for the transparent conductive film are ITO, IZO, tin oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), zinc oxide, antimony-doped zinc oxide (AZO), gallium-doped zinc oxide ( GZO).

  The sheet resistance of the counter electrode 108 is preferably 10 kΩ / □ or less, more preferably 1 kΩ / □ or less when the readout circuit 116 is of the CMOS type. When the readout circuit 116 is a CCD type, it is preferably 1 kΩ / □ or less, more preferably 0.1 kΩ / □ or less.

<Sealing film>
The following conditions are required for the sealing film 110.
First, it is possible to protect the photoelectric conversion layer by preventing intrusion of a factor that degrades the photoelectric conversion material contained in the solution, plasma, or the like in each manufacturing process of the stacked solid-state imaging device.
Second, after manufacturing the stacked solid-state imaging device, the penetration of factors that deteriorate the photoelectric conversion material such as water molecules is prevented, and the deterioration of the photoelectric conversion layer is prevented over a long period of storage / use.
Third, when forming the sealing film 110, the already formed photoelectric conversion layer is not deteriorated.
Fourth, since the incident light reaches the photoelectric conversion layer through the sealing film 110, the sealing film must be transparent to light having a wavelength detected by the photoelectric conversion layer.

The sealing film 110 can be composed of a thin film made of a single material. However, by providing a multi-layered structure and providing each layer with a different function, stress relaxation of the entire sealing film 110 and generation of dust during the manufacturing process are possible. Such effects as the suppression of defects such as cracks and pinholes caused by the above, and the optimization of material development can be expected. For example, the sealing film 110 is formed by laminating a “sealing auxiliary layer” having a function that is difficult to achieve on a layer that serves the original purpose of preventing penetration of deterioration factors such as water molecules. A two-layer structure can be formed. Although it is possible to have three or more layers, it is preferable that the number of layers is as small as possible in consideration of manufacturing costs.

<Formation of sealing film by atomic layer deposition method>
The performance of photoelectric conversion materials including organic materials is significantly deteriorated due to the presence of deterioration factors such as water molecules. Therefore, it is necessary to cover and seal the entire photoelectric conversion layer with ceramics such as dense metal oxide / metal nitride / metal nitride oxide that does not allow water molecules to permeate, diamond-like carbon (DLC), or the like. Conventionally, aluminum oxide, silicon oxide, silicon nitride, silicon nitride oxide, their laminated structure, laminated structure of them and organic polymer, etc. are used as the sealing film 110 by various vacuum film forming techniques. However, since these conventional sealing films 110 are difficult to grow a thin film at steps due to structures on the substrate surface, minute defects on the substrate surface, particles adhering to the substrate surface, etc. (because the steps become shadows), they are flat portions. The film thickness becomes significantly thinner than For this reason, the step portion becomes a path through which the deterioration factor penetrates. In order to completely cover the step with the sealing film 110, it was necessary to form the film so as to have a film thickness of 1 μm or more in the flat portion, and to increase the thickness of the sealing film 110 as a whole.

In a stacked solid-state imaging device having a pixel size of less than 2 μm, particularly about 1 μm, if the distance between the color filter and the photoelectric conversion layer, that is, the film thickness of the sealing film 110 is large, the incident light is diffracted / Divergence occurs and color mixing occurs. For this reason, a material / manufacturing method of the sealing film 110 is necessary for the stacked solid-state imaging device having a pixel size of about 1 μm so that the device performance does not deteriorate even if the film thickness of the entire sealing film 110 is reduced. Become.

The atomic layer deposition (ALD) method is a kind of CVD method, and adsorption / reaction of organometallic compound molecules, metal halide molecules, and metal hydride molecules, which are thin film materials, onto the substrate surface and unreacted groups contained therein. Is a technique for forming a thin film by alternately repeating decomposition. When the thin film material reaches the substrate surface, it is in the above-mentioned low molecular state, so that the thin film can be grown in a very small space where the low molecule can enter. For this reason, the step portion, which was difficult with the conventional thin film formation method, is completely covered (the thickness of the thin film grown on the step portion is the same as the thickness of the thin film grown on the flat portion), that is, the step coverage is very high. Excellent. For this reason, steps due to structures on the substrate surface, minute defects on the substrate surface, particles adhering to the substrate surface, and the like can be completely covered, and such a step portion does not become an intrusion path for a deterioration factor of the photoelectric conversion material. When the sealing film 110 is formed by the atomic layer deposition method, the required thickness of the sealing film 110 can be reduced more effectively than in the prior art.

  In the case where the sealing film 110 is formed by the atomic layer deposition method, a material corresponding to ceramics preferable for the sealing film 110 described above can be selected as appropriate. However, since the photoelectric conversion layer of the present invention uses an organic photoelectric conversion material, it is limited to a material capable of growing a thin film at a relatively low temperature so that the organic photoelectric conversion material does not deteriorate. According to the atomic layer deposition method using alkyl aluminum or aluminum halide as the material, a dense aluminum oxide thin film can be formed at less than 200 ° C. at which the organic photoelectric conversion material does not deteriorate. In particular, when trimethylaluminum is used, an aluminum oxide thin film can be formed even at about 100 ° C. Silicon oxide and titanium oxide are also preferable because a dense thin film can be formed at less than 200 ° C., similarly to aluminum oxide, by appropriately selecting materials.

<Color filter>
A color filter 111 is provided in each of the plurality of pixel portions. In addition, the partition 112 provided between the adjacent color filters 111 among the plurality of pixel portions functions as a light condensing unit for condensing light incident on the pixel portion onto the photoelectric conversion layer of the pixel portion. The color filter manufacturing process includes a light shielding layer forming process, a first color filter forming process, a second color filter forming process, a third color filter forming process, and a partition forming process.
As the light shielding layer 113, any one of the first to third color filters may be formed outside the effective pixel region, and the process of forming only the light shielding layer 113 can be omitted, thereby reducing the manufacturing cost. The partition wall forming process can be performed after the light shielding layer forming process, after the first color filter forming process, after the second color filter forming process, or after the third color filter forming process. It can select suitably by the combination of a method.

This specification discloses the following matters.
(1) A method for manufacturing a solid-state imaging device, comprising: a substrate; an organic film provided on the substrate; and a pixel region that generates a charge in response to light incident on the organic film,
A deposition step of depositing the organic film on the light incident side surface of the substrate;
After the vapor deposition step, before forming another film on the organic film, by exposing the vapor deposited organic film to a magnetic field, a particle removal step of removing particles attached to the surface of the organic film; A method for manufacturing a solid-state imaging device.
(2) It is a manufacturing method of the solid-state image sensing device given in (1),
A method for manufacturing a solid-state imaging device, wherein in the particle removal step, the magnetic field is formed using a magnet, and the particles are attracted to the magnet.
(3) A method for producing a solid-state imaging device according to (1) or (2),
A method of manufacturing a solid-state imaging device, wherein the organic film is patterned using a silicon mask in the vapor deposition step.
(4) The method for manufacturing a solid-state imaging device according to any one of (1) to (3),
A pixel electrode forming step of forming a transparent electrode on the organic film after the particle removing step;
And a sealing film forming step of forming a sealing film covering the pixel electrode.
(5) The method for manufacturing a solid-state imaging device according to any one of (1) to (4),
The solid-state imaging device has a plurality of pixel portions, and the pixel portions are shared by the pixel electrodes, the organic film provided above the pixel electrodes, and the plurality of pixel portions above the organic film. A manufacturing method of a solid-state image sensor including a counter electrode provided.
(6) A method for manufacturing a solid-state imaging device, comprising: a substrate; an organic film provided on the substrate; and a pixel region that generates charges in response to light incident on the organic film,
A method for producing a solid-state imaging device, comprising: a vapor deposition step of pattern vapor-depositing the organic film on a light incident side surface of the substrate using a silicon mask.

DESCRIPTION OF SYMBOLS 100 Solid-state image sensor 101 Substrate 104 Pixel electrode 107 Organic film 108 Counter electrode 110 Sealing film M Mask MG Magnet

Claims (5)

A method for manufacturing a solid-state imaging device, comprising: a substrate; an organic film provided on the substrate; and a pixel region that generates a charge in response to light incident on the organic film,
A deposition step of depositing the organic film on the light incident side surface of the substrate;
After the deposition process, before depositing another film on the organic film, by exposing the organic film deposited on the magnetic field, and a metal removing step of removing the metal adhered to the organic membrane surface, A method for manufacturing a solid-state imaging device. It is a manufacturing method of the solid-state image sensing device according to claim 1,
A method of manufacturing a solid-state imaging device, wherein in the metal removal step, the magnetic field is formed using a magnet, and the metal is attracted to the magnet. It is a manufacturing method of the solid-state image sensing device according to claim 1 or 2,
A method of manufacturing a solid-state imaging device, wherein the organic film is patterned using a silicon mask in the vapor deposition step. It is a manufacturing method of the solid-state image sensing device according to any one of claims 1 to 3,
A counter electrode forming step of forming a transparent counter electrode on the organic film after the metal removing step;
And a sealing film forming step of forming a sealing film covering the counter electrode. It is a manufacturing method of the solid-state image sensing device according to any one of claims 1 to 4,
The solid-state imaging device has a plurality of pixel portions, and the pixel portions are shared by the pixel electrodes, the organic film provided above the pixel electrodes, and the plurality of pixel portions above the organic film. A manufacturing method of a solid-state image sensor including a counter electrode provided.

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