WO2021035486A1 - 一种钽酸锂晶片及其黑化方法 - Google Patents

一种钽酸锂晶片及其黑化方法 Download PDF

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WO2021035486A1
WO2021035486A1 PCT/CN2019/102602 CN2019102602W WO2021035486A1 WO 2021035486 A1 WO2021035486 A1 WO 2021035486A1 CN 2019102602 W CN2019102602 W CN 2019102602W WO 2021035486 A1 WO2021035486 A1 WO 2021035486A1
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Prior art keywords
lithium tantalate
wafer
blackening
powder
release agent
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PCT/CN2019/102602
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English (en)
French (fr)
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杨胜裕
枋明辉
路林
黄世维
陈少斌
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福建晶安光电有限公司
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Priority to PCT/CN2019/102602 priority Critical patent/WO2021035486A1/zh
Priority to CN202311422740.XA priority patent/CN117568931A/zh
Priority to JP2021572880A priority patent/JP7330302B2/ja
Priority to CN201980005933.0A priority patent/CN112714805B/zh
Publication of WO2021035486A1 publication Critical patent/WO2021035486A1/zh
Priority to US17/679,635 priority patent/US20220178049A1/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/22—Complex oxides
    • C30B29/30—Niobates; Vanadates; Tantalates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C30B33/02—Heat treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/093—Forming inorganic materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/853—Ceramic compositions
    • H10N30/8542—Alkali metal based oxides, e.g. lithium, sodium or potassium niobates

Definitions

  • This case relates to a lithium tantalate wafer and its blackening method, in particular to an opaque lithium tantalate wafer.
  • Lithium tantalate (LiTaO 3 , LT) crystal is a multi-functional material with excellent piezoelectric, ferroelectric, acousto-optic and electro-optic effects, so it has become an important component in surface acoustic wave (SAW) devices, optical communications, lasers, and optoelectronics.
  • SAW surface acoustic wave
  • Basic functional materials Widely used in the manufacture of electronic communication devices such as resonators, filters, transducers, etc., especially in the manufacture of high-frequency surface acoustic wave devices with good electromechanical coupling, temperature coefficient and other comprehensive properties, and used in mobile phones, walkie-talkies, and satellite communications , Aerospace and many other high-end communications fields.
  • the medium and high frequency SAW devices under the 5G standard have no other more advantageous materials to replace it.
  • the lithium tantalate (LiTaO 3 , LT) crystal In the preparation of SAW devices, the lithium tantalate (LiTaO 3 , LT) crystal must be cut, ground, polished and other processes to become a lithium tantalate wafer, and then sputtered, photolithographic, etc. on the lithium tantalate wafer The procedure prepares a metal comb electrode.
  • the metal comb electrodes on the lithium tantalate wafers need to be thinner and thinner. Therefore, there are two major problems in the production of the lithium tantalate wafers in the SAW filter device, which will lead to the device yield Reduce and increase production costs.
  • LT crystal has high pyroelectric coefficient (23 ⁇ 10-5C/(m2.K)) and extremely high resistivity (1013 ⁇ cm ⁇ 1015 ⁇ cm), it is easy to be affected by temperature changes in the production of SAW filter devices. The difference is that a large amount of static charge accumulates on the surface of the lithium tantalate wafer. These static charges will be spontaneously released between the metal interdigital electrodes or the surface of the wafer, which will lead to problems such as chip cracking or burning of the metal interdigital electrode.
  • the light that passes through the substrate in the photolithography process which is one of the manufacturing processes of the SAW filter device, is reflected on the back of the substrate and returns to the surface, resulting in a decrease in the pattern formed. Resolution problem.
  • LT crystals can change the resistivity and color through reduction treatment.
  • the oxygen in the lithium tantalate wafer will react with reaction media such as hydrogen or nitrogen in a non-oxidizing atmosphere to reduce the resistance.
  • reaction media such as hydrogen or nitrogen in a non-oxidizing atmosphere
  • the wafer turns from white or light yellow to colored, usually gray or brown, so this reduction treatment is called "blackening". It can be seen that through blackening the lithium tantalate wafer can effectively reduce the resistivity and increase the resolution of the subsequent pattern, so that the yield of the SAW filter device is greatly improved, thereby reducing the manufacturing cost.
  • This process requires The high-unit price lithium tantalate crystal substrate is first made into a blackened clip at high temperature, and the flatness of the substrate is high, and it needs to be polished, otherwise it is difficult to ensure that the two wafers can be closely attached, and the two wafers must be closely attached.
  • the secondary reduction treatment leads to complex process, long process time, and high processing cost. After repeated verifications, the uniformity of the blackened color tends to show the state of black center white on the outer ring, and the process stability is not easy to be affected by the blackened substrate of the deep reduction treatment. Control, resulting in poor uniformity and affecting the accuracy of the subsequent exposure process.
  • Chinese patent CN1324167C Japan's Sumitomo Corporation proposed to use C, Si powder or placed in C, Si container to embed powder heat treatment of lithium tantalate crystals in the form of blanks, and also proposed the use of metal powders of Ca, Al, Ti, Zn and Si
  • the powder-embedded heat treatment of the lithium tantalate crystal in the form of a wafer due to the strong reduction of the metal element, makes the crystal easy to over-oxidize or destroy the piezoelectric characteristics of the crystal.
  • the same inventor Chinese patent CN100348785C also proposed to use Al and Al2O3 mixed powder to obtain a blackened lithium tantalate crystal substrate after reduction heat treatment in a gas atmosphere such as flowing N2, H2, and CO.
  • This metal powder reduction process has certain difficulties in adjusting the proportion and uniformity of the mixed powder, and affects the inconsistency of the color of the wafer after blackening. Summary of the invention
  • the present invention provides a solution to the above-mentioned problems, that is, a lithium tantalate wafer is provided.
  • a lithium tantalate wafer is provided.
  • the surface charge that has been generated does not accumulate, so that the The surface charge generated by the application of temperature disappears, and at the same time, it is possible to maintain a single polarization structure and exert effective piezoelectricity.
  • a lithium tantalate wafer of the present invention at least part of the surface of the wafer has an oxygen concentration of less than 13wt%, and the surface of this part of the wafer is the main working surface of the lithium tantalate wafer.
  • a greater concentration of oxygen holes is achieved by reducing the oxygen concentration, Reducing resistivity and increasing oxygen vacancies increase the space for electrons to move inside the material, thereby increasing the conductivity of the wafer; pentavalent tantalum itself is relatively stable, and the present invention reduces the oxygen concentration of the wafer to form an oxygen-deficient state in the wafer. Enhancing the activity of pentavalent tantalum, pentavalent tantalum can be reduced to produce tetravalent tantalum in an oxygen-deficient state.
  • the surface of the wafer includes a depth of 0-50 ⁇ m to the inside of the wafer.
  • the blackening is actually a "total" reaction, but there is a difference in the degree of the surface and the inside.
  • the thickness is polished off after blackening. The more the total amount, the lighter the color of the wafer. If you look at the oxygen content data, there is little difference between the surface and the inside.
  • At least part of the wafer surface has an oxygen concentration of less than 12.5% by weight. From the perspective of reducing light transmittance and increasing conductivity, relatively speaking, an oxygen concentration below this value has better technical effects. It is a chip color center with better absorption of visible light and higher conductivity.
  • 80% to 95% of the wafer surface or more than 95% of the wafer surface has an oxygen concentration of 11.5% to 12.5% by weight.
  • the transmittance of the wafer is less than 1% under the light wavelength of 350nm to 450nm exposure light source, and the light wavelength of 350nm to 450nm is the commonly used G line/I line band (commonly used exposure light source for semiconductor exposure equipment) .
  • the wafer has a transmittance of 0% when irradiated by an exposure light source with a light wavelength of 350 nm to 450 nm, where 0% refers to substantially no light.
  • the chromaticity of the wafer is not greater than 60, and the chromaticity can be measured with a surface spectrophotometer.
  • the principle is to measure the brightness of the surface of the object. Usually after black and white calibration, the instrument is used to perform the measurement on the surface of the object. Brightness detection is a common color measurement standard.
  • the resistance of the wafer is not greater than 9*10 10 ⁇ cm.
  • the present invention provides a method for blackening lithium tantalate wafers in order to solve the shortcomings of the above-mentioned background technology, including the lack of uniformity caused by the clamping method and the various process problems of the traditional powder embedding process.
  • the principle is the oxygen abstraction reaction (reduction reaction). This method uses the added reagents to replace the oxygen in the material composition to make the material form an oxygen-deficient anoxic state, and the pentavalent tantalum is converted into tetravalent tantalum to form an appearance of color change.
  • the tantalic acid is heated and heated at the Curie temperature under a non-oxidizing atmosphere such as reducing or inert.
  • the lithium wafer undergoes reduction treatment, and the reduction medium is a mixed powder.
  • the reduction medium includes: a reduction powder with reducing characteristics and a catalyst that can accelerate the reduction process.
  • the catalyst is heated and decomposes into a reducing gas to contact the wafer.
  • the reduced powder includes one or more carbonates.
  • the carbon dioxide decomposed by the carbonate and the reducing gas generate carbon monoxide, and the carbon monoxide reacts with the pentavalent tantalum in the lithium tantalate wafer to generate carbon dioxide and tetravalent tantalum.
  • Valence tantalum through experiments, it is found that lithium carbonate has a better reduction effect, while other reducing materials such as metal powders with higher activity (iron, zinc, aluminum, copper or cesium powder) are not as effective as carbonate powders and may be stained.
  • the sintered hard material is on the surface of the wafer and is difficult to remove.
  • the catalyst includes organic matter with carboxyl groups, and unsaturated monomer chemical materials with high activity are selected, and only a small proportion, for example, 3% to 5% of the catalyst is added to the base powder, and the overall reduction medium is uniformly mixed. It is still in a powder state, and the carboxyl group can generate carbon monoxide after heating.
  • the catalyst includes unsaturated polyester resin, polyester acrylate, epoxy acrylate, and urethane acrylate.
  • the reducing medium also includes a release agent, which can promote the separation of the reducing medium from the lithium tantalate wafer, and the pure reduced powder and catalyst are easy to agglomerate after high-temperature sintering, and there is powder sintering residue on the surface of the wafer.
  • a release agent which can promote the separation of the reducing medium from the lithium tantalate wafer, and the pure reduced powder and catalyst are easy to agglomerate after high-temperature sintering, and there is powder sintering residue on the surface of the wafer.
  • it is difficult to increase the operation, and the chip fragmentation rate is high. Adding a release agent to the reducing medium can improve this type of problem.
  • the release agent includes non-metal oxide powder.
  • a release agent materials with a high melting point may be used. Because the reaction temperature of the present invention is around 400°C, a material with a melting point far greater than 400°C, for example, more than 1000°C, is selected to ensure that it does not participate in the reduction reaction during the process, and it will not sinter into agglomerates by itself. When the catalyst is reacted at a high temperature Then it can provide structural support to maintain breathability. Considering that the process needs to be stable and does not participate in the reaction to select non-metal oxides, the stability of general oxides is relatively high.
  • silicon dioxide is used as the release agent, and silicon carbide powder or silicon powder can also be selected as the release agent.
  • the weight ratio of the reduced powder is 50% to 95%
  • the weight ratio of the catalyst is 3% to 45%
  • the weight ratio of the release agent is 2% to 5%.
  • the weight of the reducing powder accounts for 85% to 95%
  • the catalyst accounts for 3% to 5% or 5% to 10% of the reducing medium
  • the release agent accounts for 2% to 95% by weight. 5%.
  • the difference between the particle size of the reduced powder and the particle size of the release agent does not exceed 10% of the particle size of the reduced powder.
  • the heating temperature is 350°C to 450°C, or 450°C to 560°C.
  • Traditional processes have poor response effects at low temperatures, such as less than 450°C, and cannot effectively increase the blackening depth of the wafer.
  • the temperature reaches a certain temperature, such as greater than 450°C, the powder will easily leave sintered particles on the surface of the wafer, resulting in complicated subsequent processing of the wafer surface.
  • the reduction treatment is close to the Curie temperature (603 °C) of LT (lithium tantalate) material, the furnace may be subject to excessive local temperature difference, resulting in local depolarization of the wafer and loss of pressure Electrical material properties.
  • the reduction reaction is carried out in a cylindrical jig with a porous structure on the side wall that is resistant to high temperature deformation.
  • the non-oxidizing atmosphere includes hydrogen or nitrogen.
  • Hydrogen can also be mixed with nitrogen to form a reducing gas. Both have different degrees of promotion of the reduction reaction. As an experimental conclusion, if the non-oxidizing atmosphere is carbon monoxide, almost It does not promote the reduction reaction.
  • the wafer has a transmittance of 0% under irradiation with a light wavelength of 350 nm to 450 nm.
  • the metal comb-shaped electrode is prepared by grinding and sputtering the above-mentioned lithium tantalate wafer, and finally the piezoelectric substrate of the piezoelectric chip is produced.
  • the reducing medium has the advantages of good oxygen absorptive capacity at low temperature and no sintered powder remains on the surface of the wafer. It has been verified that the reduction treatment time including the heating time is 3 hours to 3 hours at 350°C to 450°C. After 5 hours, it takes about 24 hours to cool down until the chip can be taken out. The color can be changed from white to dark black. With a ventilated cylindrical fixture to increase the flow distribution of the reducing atmosphere, the complexity of the traditional blackening process is greatly reduced and the process is shortened. Time, more effectively improve the pattern resolution problem caused by the reflection of light in the photolithography process of making the metal comb-shaped electrode, and greatly improve the photolithography yield.
  • Figure 1 is a schematic cross-sectional view of the cylindrical jig of the present invention
  • Figure 2 is a schematic diagram of the appearance of the cylindrical jig of the present invention.
  • the present invention mainly solves the shortcomings of the above-mentioned patents, including the lack of uniformity caused by the clamping method and various process problems of the traditional powder embedding technology.
  • the invention uses a substrate powder to add a catalyst and a release agent as a medium, and the lithium tantalate wafer is buried in the medium and placed in a reducing atmosphere furnace for reduction treatment, so that the lithium tantalate wafer is converted from white/yellow to brown or black , Reduce the impedance and reduce the penetration rate.
  • the process can obtain a good degree of blackening at a relatively low temperature and greatly shorten the process time.
  • the powder is in a loose state, and the surface can be easily cleaned with a brush without residues, which overcomes the traditional burying process
  • the problem of unloading is different from the conventional blackening process after cutting, and the present invention can be applied to both cut and polished wafers.
  • the lithium tantalate wafers to be processed are stacked and placed in an auxiliary tool for loading the wafers and the reducing medium, for example, placed in a quartz tube, and a substrate is placed between the substrate and the substrate.
  • Layer reducing medium heated at 350°C to 450°C in a non-oxidizing atmosphere with a flow rate of 1L/min to 3L/min, and the reduction treatment time is 2 hours to 4 hours. After cooling to room temperature, take it out to get the resistance.
  • Lithium tantalate wafers with a rate of 1*10 10 ⁇ cm to 9*10 11 ⁇ cm and a brown-black color.
  • the oxygen concentration on the surface of the obtained lithium tantalate wafer is 12wt% to 13wt%, and the oxygen concentration can be confirmed and analyzed by the energy spectrometer EDS. According to chromaticity measurement, when the oxygen concentration is 13% by weight, the chromaticity of the lithium tantalate wafer is about 60, and when the oxygen concentration is 12% by weight, the chromaticity of the lithium tantalate wafer is about 50. As the oxygen concentration decreases, The chromaticity of the lithium tantalate wafer decreases accordingly.
  • the transmittance of the lithium tantalate chip is less than 1% under the light wavelength of 350nm to 450nm exposure light source, and the light wavelength of 350nm to 450nm is the commonly used G line/I Line band.
  • the reducing medium includes reducing powder and catalyst, wherein the weight of the base powder accounts for 55% to 97%, and the weight of catalyst accounts for 3% to 45%.
  • the components are placed in a mixer before use and fully stirred.
  • the reducing powder used in this embodiment is a carbonate or multiple carbonate powders with a particle size ranging from #100 to #1000 (that is, the particle size is 10 ⁇ m to 100 ⁇ m), and the particle size will affect the reduction reaction.
  • the reduced powder can be used repeatedly in this embodiment. For example, lithium carbonate particles are used in this embodiment.
  • the catalyst used in this embodiment is an organic substance with carboxyl groups, such as unsaturated polyester resins or acrylic esters.
  • the basic chemical group in organic chemistry-carboxyl consists of one carbon atom, two oxygen atoms and A hydrogen atom is composed of the chemical formula -COOH, and an increased proportion of the catalyst can condense the reducing medium. Adding these highly reactive chemical materials to the reducing medium can accelerate the reaction, mainly because the functional groups at the ends of the polyester chain can react with metal oxides. Therefore, compared with other processes, this embodiment is easier to get darker.
  • the lithium tantalate wafers to be processed are stacked and placed in an auxiliary tool for loading the wafers and the reducing medium, such as placed in a quartz tube, and a substrate is placed between the substrate and the substrate.
  • Layer reducing medium heated at 350°C to 450°C in a non-oxidizing atmosphere with a flow rate of 1L/min to 3L/min, and the reduction treatment time is 2 hours to 4 hours. After cooling to room temperature, take it out to get the resistance.
  • Lithium tantalate wafers with a rate of 1*10 10 ⁇ cm to 9*10 11 ⁇ cm and a brown-black color.
  • the oxygen concentration on the surface of the obtained lithium tantalate wafer is 12wt% to 13wt%, and the oxygen concentration can be confirmed and analyzed by the energy spectrometer EDS. According to chromaticity measurement, when the oxygen concentration is 13% by weight, the chromaticity of the lithium tantalate wafer is about 60, and when the oxygen concentration is 12% by weight, the chromaticity of the lithium tantalate wafer is about 50. As the oxygen concentration decreases, The chromaticity of the lithium tantalate wafer decreases accordingly.
  • the transmittance of the lithium tantalate chip is less than 1% under the light wavelength of 350nm to 450nm exposure light source, and the light wavelength of 350nm to 450nm is the commonly used G line/I Line band.
  • the reducing medium includes reducing powder and a release agent.
  • a catalyst can also be added to deepen the degree of blackening.
  • the weight of the base powder accounts for 50% to 95%, and the weight of the catalyst accounts for 3% to 45%.
  • the weight of the film is 2% to 5%, and the components are placed in the mixer before use and fully stirred evenly.
  • the reducing powder used in this embodiment is a carbonate or multiple carbonate powders with a particle size ranging from #100 to #1000 (that is, the particle size is 10 ⁇ m to 100 ⁇ m), and the particle size will affect the reduction reaction
  • the reduced powder can be used repeatedly in this embodiment, for example, lithium carbonate is used in this embodiment.
  • the catalyst used in this embodiment is an organic substance with carboxyl groups, such as unsaturated polyester resins or acrylic esters.
  • the basic chemical group in organic chemistry-carboxyl consists of one carbon atom, two oxygen atoms and It is composed of a hydrogen atom and has the chemical formula -COOH.
  • the release agent used in this embodiment is a non-metal oxide powder with a particle size ranging from #100 to #1000 (that is, the particle size is from 10 ⁇ m to 100 um).
  • the particle size will not affect the release effect, but mainly affect the air permeability
  • the particle size of the release agent is preferably close to or the same as the particle size of the reduced powder, and the difference between the particle size of the release agent and the particle size of the reduced powder is controlled below 10% to avoid interference or interference by the release agent. Prevent the reduced powder from contacting the wafer.
  • the release agent is set at a low temperature (not greater than 450°C) to make the reducing medium difficult to sinter into agglomerates and easy to release the film.
  • the base foundation is easy to agglomerate and hard in the process at high temperature (greater than 450°C).
  • the addition of the release agent helps the wafer Take it out, the reducing medium powder appears loose after the overall reaction. After gently pulling apart, the complete wafer can be easily removed.
  • the reducing atmosphere used in this embodiment is hydrogen or a mixture of hydrogen and nitrogen. .
  • the lithium tantalate wafers to be processed are stacked in a conventional quartz fixture, and a layer of reducing medium is spread between the substrate and the substrate, and the flow rate is 1L/min to 3L/min.
  • the reducing medium includes reducing powder, catalyst and release agent.
  • the weight of the base powder accounts for 85% to 95%, the catalyst accounts for 3% to 10%, and the release agent accounts for 2% to 5% by weight. , Put each component into the mixer before use and mix it evenly. By increasing the heating temperature, the reduction effect of the lithium tantalate wafer is improved.
  • the reducing powder used in this embodiment is a carbonate or multiple carbonate powders with a particle size ranging from #100 to #1000 (that is, the particle size is 10 ⁇ m to 100 ⁇ m), and the particle size will affect the reduction reaction Experiments show that the smaller the particle size of the reduced powder, the more uniform the blackening effect.
  • the reduced powder can be used repeatedly in this embodiment.
  • the reduced powder in this embodiment uses lithium carbonate.
  • the catalyst takes up a large proportion and presents a paste, it is not easy to spread evenly on both sides, and even during the turning process, it is easy to cause a layer of reaction medium that was evenly spread on the other side to flow again due to the influence of gravity, so it may need to be increased.
  • Baking is the process of fixing the reducing medium. Although a high proportion of the catalyst can condense the reducing medium, it is easy to cause shrinkage and cracking of the surface coating layer during the high temperature process. The cracks will cause the reaction medium to be in contact with the wafer, resulting in localized conditions.
  • the catalyst weight ratio is reduced to 3% to 10%.
  • the powder is evenly spread on the wafer and compacted so that the wafer is fully in contact with the powder, and the reduction medium can be aggregated without baking during the process.
  • the catalyst used in this embodiment is an organic substance with carboxyl groups, such as unsaturated polyester resins or acrylic esters.
  • the basic chemical group in organic chemistry-carboxyl consists of one carbon atom, two oxygen atoms and It is composed of a hydrogen atom and has the chemical formula -COOH.
  • the release agent used in this embodiment is a non-metal oxide powder with a particle size ranging from #100 to #1000.
  • the reducing atmosphere used in this embodiment is hydrogen or a mixed gas of hydrogen and nitrogen.
  • the lithium tantalate wafers 100 to be processed are stacked and placed in a ventilating cylindrical jig 200 resistant to high temperature deformation, in order to save the reaction medium and facilitate The coating covers the entire circular wafer, so the circular cylindrical jig 200 is more appropriate and saves reducing media materials.
  • the cylindrical jig 200 includes air holes 201 to allow the reactant gas to enter the reaction and allow the reacted
  • the carbon dioxide is discharged to avoid accumulation in the inside and cause unevenness, and the pores 201 can help the reactant gas to enter and participate in the reaction, and help the reacted gas to exhaust.
  • the transmittance of the lithium tantalate wafer is close to 0% under the irradiation of an exposure light source with a light wavelength of 350 nm to 450 nm.
  • the oxygen concentration is 11.5% by weight, the chromaticity of the lithium tantalate wafer is about 43.
  • the composition of the reducing medium used in this embodiment includes: reducing powder, catalyst, and release agent.
  • the base powder accounts for 85% to 95% by weight
  • the catalyst accounts for 3% to 10% by weight
  • the release agent accounts for 2% to 5% by weight. Put the components in the mixer before use and stir them fully. Evenly.
  • the reducing powder used in this embodiment is a carbonate or multiple carbonate powders with a particle size ranging from #100 to #1000 (that is, the particle size is 10 ⁇ m to 100 ⁇ m), and the particle size will affect the reduction reaction
  • the reduced powder can be used repeatedly in this embodiment, for example, lithium carbonate is used in this embodiment.
  • the catalyst used in this embodiment is an organic substance with carboxyl groups, such as unsaturated polyester resins or acrylic esters.
  • the basic chemical group in organic chemistry-carboxyl consists of one carbon atom, two oxygen atoms and It is composed of a hydrogen atom and has the chemical formula -COOH.
  • the release agent used in this embodiment is a non-metal oxide powder, which can reduce the difficulty of separating the reducing medium from the lithium tantalate wafer after the reduction reaction.
  • the particle size ranges from #100 to #1000 (ie, particle size). 10 ⁇ m to 100 ⁇ m), although the particle size will not affect the release effect too much, it will affect the air permeability.
  • the particle size of the release agent should be close to or consistent with the particle size of the reduced powder to avoid Affecting the uniform contact between the reduced powder and the wafer
  • the reducing atmosphere used in this embodiment is hydrogen or a mixture of hydrogen and nitrogen. The use of hydrogen can achieve a darker performance at a relatively low temperature.
  • a lithium tantalate wafer with a resistivity of 1*10 9 ⁇ cm to 9*10 10 ⁇ cm and a dark black color can be obtained, so there is no pyroelectricity, and the obtained lithium tantalate wafer has an oxygen concentration on its surface. 11.5% by weight to 12.5% by weight, the lithium tantalate wafer has a transmittance close to 0% under the exposure of an exposure light source with a light wavelength of 350nm to 450nm, and changes from colorless and transparent to colored and opaque. At the same time, it is fully functional as piezoelectric The characteristics of the material.

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Abstract

一种钽酸锂晶片及其黑化方法，通过在低于居里温度的还原性环境里进行黑化反应，压电晶片表面具有小于13wt％的氧浓度，该氧浓度下的压电晶片具有较低的电阻率，在波长350～450nm的光照射下透射率为0％，有效降低电阻率、提高后段图案的分辨率，使其制作的滤波器器件良率大幅提升，进而降低制造成本。

Description

一种钽酸锂晶片及其黑化方法 技术领域
本案涉及一种钽酸锂晶片及其黑化方法，特别是一种不透光的钽酸锂晶片。
背景技术
钽酸锂(LiTaO 3，LT)晶体是一种多功能材料，具有优良的压电、铁电、声光及电光效应，因而成为表面声波(SAW)器件、光通讯、激光及光电子领域中的基本功能材料。广泛应用于谐振器、滤波器、换能器等电子通讯器件的制造，尤其以良好的机电耦合、温度系数等综合性能而被用于制造高频声表面波器件，并应用于手机、对讲机、卫星通讯、航空航天等许多高端通讯领域。目前在5G标准下的中、高频SAW器件还没有其他更具有优势的材料可以替代它。
SAW器件的制备须先将钽酸锂(LiTaO 3，LT)晶体经过切割、研磨、抛光等多段工序后成为钽酸锂晶片，再于钽酸锂晶片上透过溅镀法、光刻等其他工序制备金属梳状电极。然而随着频率的提高，钽酸锂晶片上的金属梳状电极需将往薄且细趋势制备，故于钽酸锂晶片于SAW滤波器器件制作中出现两个主要问题，将导致器件成品率降低、增加生产成本。
第一，因LT晶体具有高的热释电系数(23×10-5C/(m2.K))和极高的电阻率(1013Ωcm～1015Ωcm)，故于SAW滤波器器件制作中容易受温度变化差异在钽酸锂晶片表面积累大量的静电荷，这些静电荷会在金属叉指电极间或晶片表面自发释放，进而导致晶片开裂或金属叉指电极烧毁等问题。
第二，因钽酸锂晶片高的光透射率，使得在SAW滤波器器件制造工序之一的光刻工序中透过基板内的光在基板背面反射并返回到表面，产生降低所形成图案的分辨率的问题。
经过学者研究发现，LT晶体能透过还原处理来改变电阻率和颜色，此还原处理过程中钽酸锂晶片中的氧会与非氧化气氛中的氢气或者氮气等反应介质产生反应，进而降低电阻率，同时晶片由白色或淡黄色转变为有色化，通常会是灰色或棕色，故将此还原处理称作为“黑化”。由此可知，钽酸锂晶片透过黑化可以有 效降低电阻率及提高后段图案的分辨率，使其SAW滤波器器件良率大幅提升，进而降低制造成本。
目前钽酸锂晶片黑化做法有中国专利CN100424235C，日本信越公司提出将钽酸锂、铌酸锂及储氢金属先进行深度还原处理，深度还原处理需在流通的还原性气体或惰性气体中对待处理的钽酸锂晶体基片进行高温深度还原处理后获得黑化基片，然后将深度还原处理过的基片与待处理的钽酸锂晶片交替层叠进行还原处理的方法，此种工艺需要以高单价钽酸锂晶体基片先经高温制作成黑化后的夹片，且对基片平整度要求高，需经过研磨加工，否则难以保证两种晶片能紧密贴合，且还要经过二次还原处理，导致工艺复杂、制程时间长、处理成本高，经过反复验证黑化颜色均匀性容易呈现外圈黑中心白的状况，主要受到深度还原处理的黑化基片影响制程稳定性不容易控制，导致均匀性不佳而影响后续曝光制程的精准度。
中国专利CN1324167C，日本住友公司提出使用C、Si粉或置于C、Si容器对胚料形式的钽酸锂晶体进行埋粉热处理，同时还提出使用Ca、Al、Ti、Zn及Si的金属粉末对晶片形式的钽酸锂晶体进行埋粉热处理，由于金属单质具有强的还原性，使得晶体容易过氧化或者破坏晶体压电特性。同发明人中国专利CN100348785C又提出使用Al和Al2O3混合粉末，在流动N2，H2、CO等气体气氛中进行还原热处理后获得黑化钽酸锂晶体基片。此种金属粉末还原工艺对于混合粉末调节比例及均匀性控制具有一定的难度，而影响黑化后晶片颜色深浅程度不一致。发明概述
技术问题
问题的解决方案
技术解决方案
本发明提供了上述问题的解决方法，即提供了一种钽酸锂晶片，通过提高钽酸锂晶片的导电率，使已产生的表面电荷不产生聚集现象，从而可使由于对钽酸锂晶片施加温度而产生的表面电荷消失，同时，能够维持单一极化构造而发挥有效的压电性。
本发明的一种钽酸锂晶片，至少部分晶片表面具有小于13wt％的氧浓度，该部 分晶片表面为钽酸锂晶片的主要工作表面，通过减小氧浓度实现更大的氧空穴浓度，降低电阻率，增大的氧空缺增加了电子于材料内部移动的空间，进而提升晶片的导电率；五价钽本身性质较稳固，而本发明降低晶片氧浓度，在晶片内形成缺氧态，增强五价钽的活性，在缺氧态下五价钽可经过还原反应生成四价钽。
根据本发明，优选的，晶片表面包括至晶片内部0至50μm的深度，黑化实际上是“总体性”的反应，但存在表层与内部程度上的差异，实务上黑化后研磨掉的厚度总量越多，晶片颜色越浅，如果以含氧量数据来看的话，表层与内部差异不大。
根据本发明，优选的，至少部分晶片表面具有小于12.5wt％的氧浓度，从降低透光率和增加导电率来看，相对而言，该数值以下的氧浓度具有更好的技术效果，调整为对可见光更好的吸收性的晶片色心以及更高导电率。
根据本发明，优选的，80％至95％的晶片表面或者大于95％的晶片表面具有11.5wt％至12.5wt％的氧浓度。
根据本发明，优选的，晶片在光波长为350nm至450nm的曝光光源照射下透射率小于1％，光波长为350nm至450nm是常用的G line/I Line波段(半导体曝光设备常用的曝光光源)。
根据本发明，优选的，晶片在光波长为350nm至450nm的曝光光源照射下透射率为0％，这里的0％指的是基本不透光。
根据本发明，优选的，晶片的色度不大于60，色度可用表面分光色度计进行量测，原理为量测物体表面的明暗程度，通常经过黑白校正之后，用此仪器对物体表面进行明暗度检测，为一般常见的颜色量测标准。
根据本发明，优选的，晶片的电阻不大于9*10 10Ωcm。
此外，本发明为解决上述背景技术的不足，包含夹片作法导致均匀性的不足以及传统埋粉工艺的各项制程问题，而提供了一种钽酸锂晶片的黑化方法，该黑化的原理为夺氧反应(还原反应)，本方法即利用添加的试剂将材料组成里面的氧置换反应掉，让材料形成氧空缺的缺氧态，五价钽转换成四价钽，形成外观颜色的改变。
该方法中，至少在钽酸锂晶片与晶片之间设置上一层还原介质，例如采用平铺一层还原介质，在还原或者惰性等非氧化气氛下，加热并在居里温度下对钽酸锂晶片进行还原处理，还原介质为混合粉末，还原介质包括：具有还原特性的还原粉体和能促进还原处理加速反应的催化剂，例如催化剂加热后分解成还原气体与晶片接触。
根据本发明，优选的，还原粉体包括一种或者多种碳酸盐，碳酸盐分解的二氧化碳与还原气体生成一氧化碳，一氧化碳与钽酸锂晶片中的五价钽发生还原反应生成二氧化碳和四价钽，通过实验得知碳酸锂具有较好的还原效果，而其他还原物质比如活性比较大的金属粉(铁、锌、铝、铜或铯粉)效果不如碳酸盐粉体且可能会沾烧结硬物在晶片表面而难以去除。
根据本发明，优选的，催化剂包括具备羧基的有机物，选用活性大的不饱和单体化学材料，仅需少比例，例如3％至5％的催化剂添加到基底粉体，均匀混合后整体还原介质仍呈现粉末状态，羧基加热后能生成一氧化碳。
根据本发明，优选的，催化剂包括不饱和聚酯树脂、聚酯丙烯酸酯、环氧丙烯酸酯、聚氨酯丙烯酸酯。
根据本发明，优选的，还原介质还包括脱膜剂，脱膜剂可促进还原介质与钽酸锂晶片分离，而单纯还原粉体和催化剂于高温烧结完容易结块，晶片表面存在粉末烧结残留严重，增加作业困难，晶片破片率高，在还原介质中加入脱膜剂则可改善该类问题。
根据本发明，优选的，脱膜剂包括非金属氧化物粉体。作为脱膜剂，融点高的材料可能可以使用。因为本发明反应温度在400℃附近，因此选用了一个融点远大于400℃、例如超过1000℃的材料，可以确保在过程中不参与还原反应，自身也不会烧结成块，当催化剂被高温反应后得以提供结构性的支撑维持透气性。因考量了过程需要稳定且不参与反应选择非金属氧化物，一般氧化物稳定性都相对高。本发明采用二氧化硅作为脱膜剂，也可以选用碳化硅粉或者硅粉作为脱膜剂。
根据本发明，优选的，还原粉体重量占比为50％至95％，催化剂重量占比为3％至45％，脱膜剂重量占比为2％至5％。
根据本发明，优选的，还原粉体重量占比为85％至95％，且催化剂占还原介质比重的3％至5％或者5％至10％，且脱膜剂重量占比为2％至5％。
根据本发明，优选的，还原粉体粒径与脱膜剂粒径差值不超过还原粉体粒径的10％。
根据本发明，优选的，加热温度为350℃至450℃，或者450℃至560℃。传统工艺于低温下，例如小于450℃的反应效果差，无法有效提升晶片黑化颜色深度，达到一定温度下例如大于450℃时，粉末容易于晶片表面残留烧结颗粒，造成晶片表面后续工艺处理复杂。在高温下，例如高于550℃的高温下进行还原处理，因接近LT(钽酸锂)材料居里温度(603℃)，炉子可能受到局部温差过大，导致晶片局部退极化而失去压电材料特性。
根据本发明，优选的，还原反应在耐高温形变之侧壁具有多孔结构的圆筒形治具中进行。
根据本发明，优选的，非氧化气氛包括氢气或氮气，也可以氢气混合在氮气中形成还原气体，皆对还原反应有不同程度的促进作用，作为实验结论，如果非氧化气氛为一氧化碳时，几乎对还原反应没有促进作用。
根据本发明，优选的，晶片在光波长为350nm至450nm的照射下透射率为0％。
除了上述黑化工艺外，需要知道的是，可以通过简化本发明的技术方案，仅将还原粉体和脱膜剂混合构成还原介质对晶片进行黑化。
通过对上述的钽酸锂晶片进行研磨、溅镀等工艺制备金属梳状电极，最终制得压电芯片的压电基板。
发明的有益效果
有益效果
本发明的有益效果包括但不限于：
还原介质具备于低温下就有良好的夺氧能力，并且于晶片表面不残留烧结粉体的优点，经验证于350℃至450℃的情况下，包含升温时间在内的还原处理时间3小时至5小时，降温到可以取出晶片需要约24小时，就能将由于颜色由白色转变为深黑色，搭配通气圆筒形治具增加还原气氛流动分布，大幅降低传统黑化工艺的复杂程度并且缩短工艺时间，更有效地改善制作金属梳状电极的光刻工序 中光的反射造成图案的分辨率问题，大幅提高光刻良率。
对附图的简要说明
附图说明
附图用来提供对本发明的进一步理解，并且构成说明书的一部分，与本发明的实施例一起用于解释本发明，并不构成对本发明的限制。此外，附图数据是描述概要，不是按比例绘制。
图1为本发明的筒形治具的剖视示意图；
图2为本发明的筒形治具的外观示意图。
图中标示：100、待处理的钽酸锂晶片；200、筒形治具；201、气孔。
发明实施例
本发明的实施方式
下面便结合附图对本发明若干具体实施例作进一步的详细说明。但以下关于实施例的描述及说明对本发明保护范围不构成任何限制。
应当理解，本发明所使用的术语仅出于描述具体实施方式的目的，而不是旨在限制本发明。进一步理解，当在本发明中使用术语“包含”、″包括″时，用于表明陈述的特征、整体、步骤、组件、和/或封装件的存在，而不排除一个或多个其他特征、整体、步骤、组件、封装件、和/或它们的组合的存在或增加。
除另有定义之外，本发明所使用的所有术语(包括技术术语和科学术语)具有与本发明所属领域的普通技术人员通常所理解的含义相同的含义。应进一步理解，本发明所使用的术语应被理解为具有与这些术语在本说明书的上下文和相关领域中的含义一致的含义，并且不应以理想化或过于正式的意义来理解，除本发明中明确如此定义之外。
本发明主要解决上述各项专利的不足，包含夹片作法导致均匀性的不足以及传统埋粉工艺的各项制程问题。本发明采用一种基底粉体加入催化剂与脱膜剂作为介质，将钽酸锂晶片埋入介质中置于还原气氛炉中进行还原处理，使钽酸锂晶片由白色/黄色转变成棕色或黑色，降低阻抗减少穿透率。该工艺可于相对低温下得到良好的黑化程度，大幅缩短工艺时间，工艺结束后该粉体呈现松散的状态，可轻易使用毛刷刷除干净表面不会有残留物，克服传统埋粉工艺下片的 困扰，有别于以往的制程通常于切割后进行黑化工艺，本发明可同时适用于切割、研磨状态的晶片。
在本发明的第一个实施例中，将待处理的钽酸锂晶片堆叠放置于用来装填晶片与还原介质的辅助器具中，例如置于石英圆管中，基板与基板之间铺上一层还原介质，在流量为1L/min至3L/min的非氧化气氛下，加热350℃至450℃温度条件下，还原处理时间2小时至4小时，待降温至室温后取出，即可得到电阻率1*10 10Ωcm至9*10 11Ωcm且颜色为棕黑色的钽酸锂晶片。得到的该钽酸锂晶片其表面的氧浓度为12wt％至13wt％，可通过能谱仪EDS对氧浓度进行成分确认和浓度分析。根据色度测量，氧浓度在13wt％时，钽酸锂晶片的色度约为60，而当氧浓度为12wt％时，钽酸锂晶片的色度约为50，随着氧浓度的下降，钽酸锂晶片的色度随之下降。经过日立UH4150分光亮度计测试得知，钽酸锂晶片在光波长为350nm至450nm的曝光光源照射下透射率小于1％，光波长为350nm至450nm是常用的G line/I Line波段。
其中还原介质包括还原粉体、催化剂，其中基底粉体重量占比55％至97％，催化剂重量占比为3％至45％，使用前将各组成放置入混料机中充分搅拌均匀。
本实施例所使用的还原粉体为一种碳酸盐或多种碳酸盐粉体，粒径介于#100至#1000(即粒径为10μm至100μm)，粒径大小会影响还原反应，通过实验表明，还原粉末的粒径越小黑化效果越均匀，还原粉体在本实施例中可多次反复使用，例如本实施例中采用碳酸锂颗粒。
本实施例所使用的催化剂为具备羧基的有机物，例如由不饱和聚酯树脂类或者丙烯酸酯类组成，有机化学中的基本化学基-羧基(carboxyl)，由一个碳原子、两个氧原子和一个氢原子组成，化学式-COOH，增大比例的催化剂可凝聚还原介质。在还原介质中添加这些活性大的化学材料可加速反应，主要是这些聚酯链末端的官能基可和金属氧化物反应，因此相对于其他工艺，本实施例比较容易黑。
在本发明的第二个实施例中，将待处理的钽酸锂晶片堆叠放置于用来装填晶片与还原介质的辅助器具中，例如置于石英圆管中，基板与基板之间铺上一层还原介质，在流量为1L/min至3L/min的非氧化气氛下，加热350℃至450℃温度条件 下，还原处理时间2小时至4小时，待降温至室温后取出，即可得到电阻率1*10 10Ωcm至9*10 11Ωcm且颜色为棕黑色的钽酸锂晶片。得到的该钽酸锂晶片其表面的氧浓度为12wt％至13wt％，可通过能谱仪EDS对氧浓度进行成分确认和浓度分析。根据色度测量，氧浓度在13wt％时，钽酸锂晶片的色度约为60，而当氧浓度为12wt％时，钽酸锂晶片的色度约为50，随着氧浓度的下降，钽酸锂晶片的色度随之下降。经过日立UH4150分光亮度计测试得知，钽酸锂晶片在光波长为350nm至450nm的曝光光源照射下透射率小于1％，光波长为350nm至450nm是常用的G line/I Line波段。
其中还原介质包括还原粉体和脱膜剂，本实施例中也可以加入催化剂加深黑化程度，其中基底粉体重量占比50％至95％，催化剂重量占比为3％至45％，脱膜剂重量占比为2％至5％，使用前将各组成放置入混料机中充分搅拌均匀。
本实施例所使用的还原粉体为一种碳酸盐或多种碳酸盐粉体，粒径介于#100至#1000(即粒径为10μm至100μm)，粒径大小会影响还原反应，通过实验表明，还原粉末的粒径越小黑化效果越均匀，还原粉体在本实施例中可多次反复使用，例如本实施例中采用碳酸锂。
本实施例所使用的催化剂为具备羧基的有机物，例如由不饱和聚酯树脂类或者丙烯酸酯类组成，有机化学中的基本化学基-羧基(carboxyl)，由一个碳原子、两个氧原子和一个氢原子组成，化学式-COOH。
本实施例所使用的脱膜剂为非金属氧化物粉体，粒径介于#100至#1000(即粒径为10μm至100um)，粒径不会影响脱模效果，主要会影响透气性，此外，脱膜剂的粒径最好与还原粉体粒径接近或者一致，脱模剂的粒径大小与还原粉体粒径大小差异控制在10％以下，用以避免脱膜剂干扰或者阻碍还原粉体与晶片接触。脱模剂的设置在低温下(不大于450℃)使还原介质不易烧结成块容易脱膜，高温下(大于450℃)的制程基体粉底容易结块且硬，加入脱膜剂有助于晶片取出，还原介质粉体整体反应后呈现松散的状态，轻轻拨开后，完整的晶片即可轻易取下，本实施例所使用的还原气氛为氢气、或者氢气和氮气两者的混合之气体。
在本发明的第三个实施例中，将待处理的钽酸锂晶片堆叠放置于常规石英治具 中，基板与基板之间铺上一层还原介质，在流量为1L/min至3L/min的非氧化气氛下，加热450℃至560℃温度条件下，例如采用560℃还原处理时间2小时至4小时，待降温至室温后取出。
其中还原介质包括还原粉体、催化剂和脱膜剂，其中基底粉体重量占比85％至95％，催化剂重量占比为3％至10％，脱膜剂重量占比为2％至5％，使用前将各组成放置入混料机中充分搅拌均匀。通过提高加热温度，提升钽酸锂晶片的还原效果。
本实施例所使用的还原粉体为一种碳酸盐或多种碳酸盐粉体，粒径介于#100至#1000(即粒径为10μm至100μm)，粒径大小会影响还原反应，通过实验表明，还原粉末的粒径越小黑化效果越均匀，还原粉体在本实施例中可多次反复使用，例如本实施例中还原粉体采用碳酸锂。
催化剂占比过大呈现糊状，则不容易均匀涂抹于两个面上，甚至在翻面的过程中容易因重力影响导致另一面原本涂抹均匀的一层反应介质又流动了，因此可能需要增加烘烤将还原介质固定的工艺，高比例的催化剂虽然可凝聚还原介质，但容易于高温过程中导致表面涂抹层发生收缩龟裂，裂缝处就会造成反应介质与晶片没有接触的状况，出现局部黑化不均匀的现象，且于高温过程中容易挥发，造成只留下粉体与晶片局部接触，导致不均，如蚂蚁洞的现象，晶片上也留下涂抹层收缩龟裂的痕迹。因此，在本实施例中催化剂重量占比下调至3％至10％。本实施例中将粉末均匀铺上晶片并压实使其与晶片充分与粉体接触，过程中不需要经过烘烤的动作即可实现凝聚还原介质。
本实施例所使用的催化剂为具备羧基的有机物，例如由不饱和聚酯树脂类或者丙烯酸酯类组成，有机化学中的基本化学基-羧基(carboxyl)，由一个碳原子、两个氧原子和一个氢原子组成，化学式-COOH。
本实施例所使用的脱膜剂为非金属氧化物粉体，粒径介于粒径介于#100至#1000。本实施例所使用的还原气氛为氢气或者氢气和氮气两者的混合之气体。
参考图1和图2，在本发明的第四个实施例中，将待处理的钽酸锂晶片100堆叠放置于耐高温形变之通气圆筒形治具200中，为了要节省反应介质并且容易涂布布满整个圆形晶片，因此圆形的筒形治具200会比较适当且节省还原介质材料， 筒形治具200包括气孔201是为了让反应气体能够进去参与反应，并且让反应后的二氧化碳排出避免积累在里面造成不均匀，气孔201可以帮助反应气体进入参与反应，帮助反应后的气体排气。
待处理的钽酸锂晶片100与待处理的钽酸锂晶片100之间铺上一层还原介质，在流量为1L/min至2L/min的非氧化气氛下，加热350℃至450℃温度条件下，还原处理时间0.5小时至1小时，待降温至室温后取出，即可得到电阻率1*10 9Ωcm至1*10 11Ωcm且颜色为黑色不透光的晶片。得到的该钽酸锂晶片其表面的氧浓度为11.5wt％至12.5wt％。钽酸锂晶片在光波长为350nm至450nm的曝光光源照射下透射率趋近于0％，当氧浓度为11.5wt％时，钽酸锂晶片的色度约为43。
本实施例所使用的还原介质组成包括：还原粉体、催化剂和脱膜剂。其中基底粉体重量占比85％至95％，催化剂重量占比为3％至10％，脱膜剂重量占比为2％至5％，使用前将各组成放置入混料机中充分搅拌均匀。
本实施例所使用的还原粉体为一种碳酸盐或多种碳酸盐粉体，粒径介于#100至#1000(即粒径为10μm至100μm)，粒径大小会影响还原反应，通过实验表明，还原粉末的粒径越小黑化效果越均匀，还原粉体在本实施例中可多次反复使用，例如本实施例中采用碳酸锂。
本实施例所使用的催化剂为具备羧基的有机物，例如由不饱和聚酯树脂类或者丙烯酸酯类组成，有机化学中的基本化学基-羧基(carboxyl)，由一个碳原子、两个氧原子和一个氢原子组成，化学式-COOH。
本实施例所使用的脱膜剂为非金属氧化物粉体，可降低还原反应后还原介质与钽酸锂晶片分离的难度，粒径介于粒径介于#100至#1000(即粒径为10μm至100μm)，粒径大小虽然不会给脱模效果造成太大影响，但会影响透气性，此外，脱模剂的颗粒粒径最好与还原粉体的粒径接近或者一致，避免影响还原粉体与晶片均匀接触，本实施例所使用的还原气氛为氢气或者氢气和氮气两者的混合之气体，其中使用氢气可以在相对低温下得到更黑的表现。
本实施例可得到电阻率1*10 9Ωcm至9*10 10Ωcm且颜色为深黑色的钽酸锂晶片，因此不存在热释电性，得到的该钽酸锂晶片其表面的氧浓度为11.5wt％至12.5wt％，该钽酸锂晶片在光波长为350nm至450nm的曝光光源照射下透射率趋近于0 ％，并且从无色透明变成有色不透明的同时，充分具有作为压电材料的特性。因此，不存在由于在表面弹性波组件等的组件制造工序中所受的温度变化，电荷累积在基板表面上引起火花，从而破坏形成在基板表面的图案、或者进一步在基板上产生裂缝等问题，另外，不存在在光刻工序中通过基板内的光反射在基板背面并返回到表面，从而降低所形成的图案的分辨率的问题，因此适合用于表面弹性波组件用基板上。
以上实施方式仅以钽酸锂晶片为例进行描述，实际上，本发明的设计也可适用于铌酸锂晶片，鉴于铌酸锂晶片相对钽酸锂晶片而言，黑化工艺条件要求相对低，因此本发明不再进行赘述。
以上实施方式仅用于说明本发明，而并非用于限定本发明，本领域的技术人员，在不脱离本发明的精神和范围的情况下，可以对本发明做出各种修饰和变动，因此所有等同的技术方案也属于本发明的范畴，本发明的专利保护范围应视权利要求书范围限定。

Claims (31)

  1. 一种钽酸锂晶片，其特征在于：至少部分晶片表面具有小于13wt％的氧浓度。
  2. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：晶片表面包括至晶片内部0至50μm的深度。
  3. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：至少部分晶片表面具有小于12.5wt％的氧浓度。
  4. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：80％至95％的晶片表面或者大于95％的晶片表面具有小于12.5wt％的氧浓度。
  5. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：80％至95％的晶片表面或者大于95％的晶片表面具有11.5wt％至12.5wt％的氧浓度。
  6. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：晶片在光波长为350nm至450nm的照射下透射率小于1％。
  7. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：晶片在光波长为350nm至450nm的照射下透射率为0％。
  8. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：晶片的色度L值不大于60。
  9. 根据权利要求1所述的一种钽酸锂晶片，其特征在于：晶片的电阻不大于9*10 10Ωcm。
  10. 一种钽酸锂晶片的黑化方法，至少在钽酸锂晶片与晶片之间设置上一层还原介质，在非氧化气氛下，加热并在居里温度下对钽酸锂晶片进行还原处理，还原介质为混合粉末，还原介质包括：还原粉体，经加热会分离成还原气体的催化剂。
  11. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体包括一种或者多种碳酸盐。
  12. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：催化剂包括具备羧基的有机物。
  13. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：催化剂包括不饱和聚酯树脂类或者丙烯酸酯类。
  14. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：还原介质还包括脱膜剂。
  15. 根据权利要求14所述的一种钽酸锂晶片的黑化方法，其特征在于：脱膜剂可促进还原介质与钽酸锂晶片分离。
  16. 根据权利要求14所述的一种钽酸锂晶片的黑化方法，其特征在于：脱膜剂包括非金属氧化物粉体。
  17. 根据权利要求14所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体重量占比为50％至95％，且催化剂重量占比为3％至45％，且脱膜剂重量占比为2％至5％。
  18. 根据权利要求14所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体重量占比为85％至95％，且催化剂占还原介质比重的3％至5％或者5％至10％，且脱膜剂重量占比为2％至5％。
  19. 根据权利要求14所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体粒径与脱膜剂粒径差值不超过还原粉体粒径的10％。
  20. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：加热温度为350℃至450℃，或者450℃至560℃。
  21. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：还原反应在耐高温形变之侧壁具有多孔结构的圆筒形治具中进行。
  22. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：非氧化气氛包括氢气、氮气或者二者的混合气体。
  23. 根据权利要求10所述的一种钽酸锂晶片的黑化方法，其特征在于：晶片在光波长为350nm至450nm的照射下透射率为0％。
  24. 一种钽酸锂晶片的黑化方法，至少在钽酸锂晶片与晶片之间设置上一层还原介质，在非氧化气氛下，加热并在居里温度下对钽酸锂晶片进行还原处理，还原介质为混合粉末，还原介质包括：还 原粉体和脱膜剂。
  25. 根据权利要求24所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体包括一种或者多种碳酸盐。
  26. 根据权利要求24所述的一种钽酸锂晶片的黑化方法，其特征在于：脱膜剂包括非金属氧化物粉体。
  27. 根据权利要求24所述的一种钽酸锂晶片的黑化方法，其特征在于：脱膜剂为二氧化硅粉、碳化硅粉或者硅粉。
  28. 根据权利要求24所述的一种钽酸锂晶片的黑化方法，其特征在于：还原粉体粒径与脱膜剂粒径差值不超过还原粉体粒径的10％。
  29. 根据权利要求24所述的一种钽酸锂晶片的黑化方法，其特征在于：还原介质还包括经加热会分离成还原气体的催化剂。
  30. 根据权利要求29所述的一种钽酸锂晶片的黑化方法，其特征在于：催化剂包括具备羧基的有机物。
  31. 一种钽酸锂基板，根据权利要求1至权利要求30中任意一项所述的钽酸锂晶片的黑化方法制得的压电基板。
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050265916A1 (en) * 2004-05-25 2005-12-01 Jundt Dieter H Using condensed chemicals to precondition lithium niobate and lithium tantalate crystals
CN102369612A (zh) * 2009-03-16 2012-03-07 埃赛力达技术公司 热释电材料-辐射传感器-辐射传感器的制作方法-钽酸锂和铌酸锂的用途
CN102443851A (zh) * 2010-10-13 2012-05-09 济南晶正电子科技有限公司 一种薄膜材料的剥离方法
CN106048735A (zh) * 2016-08-12 2016-10-26 天通控股股份有限公司 一种钽酸锂或铌酸锂晶体基片黑化方法
CN106544735A (zh) * 2016-12-06 2017-03-29 中国电子科技集团公司第二十六研究所 一种钽酸锂黑片的制作方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3938147B2 (ja) * 2003-04-08 2007-06-27 住友金属鉱山株式会社 タンタル酸リチウム基板およびその製造方法
JP6238478B2 (ja) 2016-03-16 2017-11-29 信越化学工業株式会社 タンタル酸リチウム単結晶基板の製造方法
JP6598378B2 (ja) 2016-11-17 2019-10-30 信越化学工業株式会社 タンタル酸リチウム単結晶基板の製造方法
JP6672243B2 (ja) * 2017-11-22 2020-03-25 Kddi株式会社 データ提供システム、データ提供装置、データ提供方法、及びデータ提供プログラム
CN110129891A (zh) * 2018-02-02 2019-08-16 福建晶安光电有限公司 一种晶片的黑化方法及黑化后晶片

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050265916A1 (en) * 2004-05-25 2005-12-01 Jundt Dieter H Using condensed chemicals to precondition lithium niobate and lithium tantalate crystals
CN102369612A (zh) * 2009-03-16 2012-03-07 埃赛力达技术公司 热释电材料-辐射传感器-辐射传感器的制作方法-钽酸锂和铌酸锂的用途
CN102443851A (zh) * 2010-10-13 2012-05-09 济南晶正电子科技有限公司 一种薄膜材料的剥离方法
CN106048735A (zh) * 2016-08-12 2016-10-26 天通控股股份有限公司 一种钽酸锂或铌酸锂晶体基片黑化方法
CN106544735A (zh) * 2016-12-06 2017-03-29 中国电子科技集团公司第二十六研究所 一种钽酸锂黑片的制作方法

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