DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election without traverse of group I, claims 1, 2, 4-11, and 13-17 in the reply filed on 4/20/2026 is acknowledged.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 2 and 4 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 2 recites the limitation "a surface of the handling substrate" in lines 2-3. There is insufficient antecedent basis for this limitation in the claim. Parent claim 1 has introduced the element of “a surface of the handling substrate” in line 8, and the limitation in claim 2 appears to be a reference back to claim 1. The examiner recommends amending claim 2 to recite “the surface of the handling substrate”.
Claim 4 recites the limitation "a surface of the handling substrate" in lines 2-3. There is insufficient antecedent basis for this limitation in the claim. Parent claim 1 has introduced the element of “a surface of the handling substrate” in line 8, and the limitation in claim 4 appears to be a reference back to claim 1. The examiner recommends amending claim 4 to recite “the surface of the handling substrate”.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-2, 4-7, 9-11 and 13-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Akiyama (EP 3306644 A1), Belhachemi (WO 2019186053 A1) and Okuyama (WO 2015008658 A1).
As to claim 1, Akiyama discloses a method of manufacturing a donor substrate for the transfer of a piezoelectric layer onto a support substrate, comprising:
providing a handling substrate (“support wafer 24”);
providing a piezoelectric substrate (“oxide single-crystal wafer 11”, which can be “an oxide single-crystal film, which is a lithium tantalate or lithium niobate film”, which is disclosed as a “typical piezoelectric material”);
performing a surface activation treatment on a surface of the piezoelectric substrate to form an activated surface of the piezoelectric substrate (“The surface 11s of the oxide single-crystal wafer 11 from which the ions have been implanted and the surface 14s of a support wafer 14 to be laminated with the oxide single-crystal wafer are both subjected to surface activation treatment by exposing them to an ion beam 15 (in step b).”); and
assembling the piezoelectric substrate on the handling substrate (“the surface 11 s of the oxide single-crystal wafer from which the ions have been implanted is bonded to the surface 14s of the support wafer to obtain a laminate 16 (in step c).”).
See the translation, disclosing:
An oxide single crystal such as lithium tantalate (LT) and lithium niobate (LN) is a typical piezoelectric material and has been used widely as a material of surface acoustic wave (SAW) devices. The oxide single crystal used as a piezoelectric material enables band broadening because an electromechanical coupling factor, which indicates the conversion efficiency of electromagnetic energy into dynamic energy, is large. However, it has low stability against a temperature change, and the frequency to which it can respond varies with the temperature change. The low stability against the temperature change owes to the thermal expansion coefficient of the oxide single crystal.
…
By using the above-described method, a composite wafer comprising a support wafer, and an oxide single-crystal film, which is a lithium tantalate or lithium niobate film, on the support wafer can be obtained. The thickness of the oxide single-crystal film of the resulting composite wafer corresponds to the implantation depth of hydrogen ions during the hydrogen ion implantation and is preferably from 100 to 1000 nm. The surface of the oxide single-crystal film may be optionally ground.
According to the invention, the method of producing a composite wafer is not particularly limited, and one of the embodiments is shown in FIG. 1. Hydrogen ions 12 are implanted into an oxide single-crystal wafer 11 through a surface thereof to form an ion-implanted layer 13 inside the oxide single-crystal wafer 11 (in step a). The surface 11s of the oxide single-crystal wafer 11 from which the ions have been implanted and the surface 14s of a support wafer 14 to be laminated with the oxide single-crystal wafer are both subjected to surface activation treatment by exposing them to an ion beam 15 (in step b). After the surface activation treatment, the surface 11 s of the oxide single-crystal wafer from which the ions have been implanted is bonded to the surface 14s of the support wafer to obtain a laminate 16 (in step c). The laminate 16 thus obtained is heat-treated at a temperature of 90°C or higher (in step d). By bringing a wedge-like blade 19 of a ultrasonic cutter into contact with a side surface of the heat treated laminate 16, that is, an end portion of the ion-implanted layer 13, and applying ultrasonic vibration to the laminate 16, the oxide single-crystal wafer can be split along the ion-implanted layer 13 to remove a portion 11b of the oxide single-crystal wafer and obtain a composite wafer 18 having an oxide single-crystal film 11a transferred onto the support wafer 14 (in step e). Another embodiment of the step e is shown in FIG. 2. In this step e, the heat-treated laminate 16 is immersed in a water tank 31 equipped with a vibrator 33, ultrasonic waves are applied to the water tank 31 so that the ultrasonic vibration is applied to the laminate 16 via a liquid 32 to split the oxide single-crystal wafer along the ion-implanted layer 13 to remove a portion 11b of the oxide single-crystal wafer and obtain a composite wafer 18 having an oxide single-crystal film 11a transferred onto a support wafer 14.
See also marked up Figure 1, below, in combination with the translation above:
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Akiyama does not disclose depositing a polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate or assembling the piezoelectric substrate on the handling substrate such that the polymer layer is between the activated surface of the piezoelectric substrate and the handling substrate.
However, Belhachemi discloses and makes obvious depositing a polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate and assembling the piezoelectric substrate on the handling substrate such that the polymer layer is between the surface of the piezoelectric substrate and the handling substrate.
See the Belhachemi translation, disclosing:
depositing a photo-polymerizable adhesive layer on the support substrate, bonding the piezoelectric substrate on the support substrate via the dielectric layer and the adhesive layer, to form an assembled substrate,
irradiating the assembled substrate with a luminous flux to polymerize the adhesive layer, said adhesive layer and the dielectric layer together forming the electrically insulating layer.
See later in the Belhachemi translation, disclosing:
The use of the polymer layer 2 as a bonding layer makes it possible, on the one hand, to bond the piezoelectric substrate 3 to the support substrate 1 in an efficient manner, in particular because the surface of the piezoelectric substrate is rough, and it is commonly accepted that a polymer material sticks more easily on a slightly rough surface. On the other hand, the deposition of the adhesive layer 2, the assembly of the substrates 1 and 3, and the irradiation of the assembled substrate 5 are carried out more quickly and in a simplified manner compared to the techniques of the state of the for which the successive deposits of SiO .sub.2 layers on the rough surface and on the surface opposite the rough surface of the piezoelectric layer are long and tedious to implement.
In addition, the proposed method has a greatly reduced cost, since the deposition and UV irradiation of the adhesive layer are much less expensive than the successive Si0 .sub.2 deposits, and do not require the realization of mechano-chemical polishing (CMP). .
The proposed polymer layer bonding also makes it possible to regulate another major problem occurring during the successive deposition of SiO .sub.2 layers, namely the creation of an undesirable large curvature in the substrate, which hinders the manufacture of radiofrequency devices from said substrate, by freeing such deposits of Si0 .sub.2 . The method of the invention thus makes it possible to avoid, or at least to reduce, the deformations of the piezoelectric substrate and the support substrate during the deposition of the dielectric layer and of the adhesive layer respectively, as well as the final substrate obtained after collage and irradiation.
Subsequently, the assembled substrate 5 is irradiated with a luminous flux 6 in order to polymerize the adhesive layer 2. The irradiation of the assembled substrate 5 is shown in FIG. 4.
Additionally, Okuyama discloses and makes obvious using a polymer layer with at least one of the activated surface of the piezoelectric substrate (“include piezoelectric materials such as PLZT is.”) or a surface of the handling substrate and assembling the piezoelectric substrate on the handling substrate such that the polymer layer is between the activated surface of the piezoelectric substrate and the handling substrate.
See the Okuyama translation, disclosing piezoelectric materials:
As the ceramic plate, Al2O3, Mullite, AlN, SiC, Si3N4, BN, crystallized glass, Cordierite, Spodumene, Pb-BSG + CaZrO3 + Al2O3, Crystallized glass + Al2ZQ, SG + BGSQ, SG + SG2G + SG3G + BGSQ Glass-ceramic, ceramics for substrates such as zero-dur, TiO2, strontium titanate, calcium titanate, magnesium titanate, alumina, MgO, steatite, BaTi4O9, BaTiO3, BaTi4 + CaZrO3, BaSrCaZrTiO3, Ba (TiZr) O3, PMN-PT And PFN-PFW Capacitor materials, PbNb2O6, Pb0.5Be0.5Nb2O6, PbTiO3, BaTiO3, PZT, 0.855PZT-95PT-0.5BT, 0.873PZT-0.97PT-0.3BT, include piezoelectric materials such as PLZT is.
As the semiconductor wafer, a silicon wafer, a semiconductor wafer, a compound semiconductor wafer, or the like can be used. The silicon wafer is obtained by processing single crystal or polycrystalline silicon on a thin plate, and is n-type or p-type. This includes all doped silicon wafers, intrinsic silicon wafers, etc., and silicon wafers with silicon oxide layers and various thin films deposited on the surface of silicon wafers. In addition to silicon wafers, germanium, silicon- Germanium, gallium-arsenic, aluminum-gallium-indium, nitrogen-phosphorus-arsenic-antimony, SiC, InP (indium phosphorus), InGaAs, GaInNAs, LT, LN, ZnO (zinc oxide), CdTe (cadmium tellurium), ZnSe ( Semiconductor wafers such as zinc selenide) It can be used as the object semiconductor wafer.
See also later in the translation, disclosing that the substrates are activated.
<Means for bonding inorganic substrate and polymer film>
In the present invention, known adhesives such as silicone resins, epoxy resins, acrylic resins, polyester resins, and pressure-sensitive adhesives can be used as means for bonding the inorganic substrate and the polymer film. In the present invention, for example, a pressure-sensitive adhesive using a side chain crystalline polymer having a property that the adhesive strength is reduced by cooling can be used.
A preferable adhesive means in the present invention is an extremely thin adhesive / adhesive layer adhesive means having a thickness of 5 μm or less, or preferably an adhesive means that does not substantially use an adhesive / adhesive.
In the present invention, the inorganic substrate side is subjected to organic treatment such as silane coupling agent treatment and UV ozone treatment, and activation treatment. Similarly, the polymer film side is also subjected to vacuum plasma treatment, atmospheric pressure plasma treatment, corona treatment, It is possible to use a joining method in which activation treatment such as flame treatment, itro treatment, UV ozone treatment, exposure treatment to an active gas, etc. is performed, and both treatment surfaces are brought into close contact with each other to perform pressurization and heat treatment.
Additionally, the Okuyama translation discloses that UV or ozone irradiation of the inorganic substrate is a preferable operation. See the following translation excerpt, disclosing:
In the present invention, it is preferable to expose the inorganic substrate to the silane coupling agent vapor while holding the silane coupling agent application surface of the inorganic substrate downward. In the liquid phase coating method, the coating surface of the inorganic substrate is inevitably facing upward during and before coating, and therefore it is impossible to deny the possibility that floating foreign substances or the like in the working environment are deposited on the surface of the inorganic substrate. However, the coating method using the gas phase can hold the inorganic substrate downward. It is possible to greatly reduce the adhesion of foreign substances in the environment.
Cleaning the surface of the inorganic substrate before the silane coupling agent treatment by means such as short wavelength UV / ozone irradiation or cleaning with a liquid cleaning agent is a significant preferable operation.
Theoretically, a single molecular layer is sufficient for the coating amount and thickness of the coupling agent, and a negligible thickness is sufficient for mechanical design. Generally, it is less than 400 nm (less than 0.4 μm), preferably 200 nm or less (0.2 μm or less), more practically 100 nm or less (0.1 μm or less), more preferably 50 nm or less, still more preferably 10 nm or less. However, when the calculation is in the region of 5 nm or less, it is assumed that the coupling agent is present not in the form of a uniform coating but in a cluster shape, which is not preferable. The film thickness of the coupling agent layer can be determined by ellipsometry or calculation from the concentration of the coupling agent solution at the time of coating and the coating amount.
In the present invention, an inorganic substrate that has been treated with a silane coupling agent, an untreated inorganic substrate, or an inorganic substrate that has been cleaned with ultrapure water or the like is activated by performing UV ozone treatment. An inorganic substrate can be used. The UV ozone treatment in the present invention means a treatment in which ultraviolet rays having a wavelength of 270 nm or less, preferably 210 nm or less, more preferably 180 nm or less are irradiated at a relatively short distance in the presence of oxygen. Short wavelength ultraviolet rays ozonize oxygen in the atmosphere, and the ultraviolet rays themselves attenuate. Therefore, if the distance between the light source and the object to be processed is increased, the effect cannot be obtained. In the present invention, the distance between the light source and the object to be processed is 30 mm or less, preferably 16 mm or less, and more preferably 8 mm or less.
In the present invention, only with the silane coupling agent treatment, the adhesive force between the inorganic substrate and the polymer film becomes too strong, which may hinder peeling. Adjustment is possible by reducing the coating amount of the silane coupling agent, but since processing spots tend to appear, in the present invention, UV ozone treatment or the like is performed after the silane coupling agent treatment and introduced by the silane coupling agent. We recommend a method of deactivating functional groups.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized depositing a polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate or assembling the piezoelectric substrate on the handling substrate such that the polymer layer is between the activated surface of the piezoelectric substrate and the handling substrate as suggested by Belhachemi and Okuyama in order to reduce makes it possible to avoid, or at least to reduce, the deformations of the piezoelectric substrate and the support substrate and to also achieve cleaning of the surfaces before the polymer bonding operations.
As to claim 2, Akiyama does not disclose that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the activated surface of the piezoelectric substrate.
However, Belhachemi and Okuyama as applied above would make obvious that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the activated surface of the piezoelectric substrate. See the citations above in claim 1; Belhachemi makes obvious the polymer layer as an adhesive layer and Okuyama discloses activating the polymer as well as the substrates.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the activated surface of the piezoelectric substrate as suggested by Belhachemi and Okuyama in order to reduce makes it possible to avoid, or at least to reduce, the deformations of the piezoelectric substrate and the support substrate and to also achieve cleaning of the surfaces before the polymer bonding operations.
As to claim 4, Akiyama does not disclose that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the handling substrate.
However, Belhachemi and Okuyama as applied above would make obvious that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the handling substrate. See the citations above in claim 1; Belhachemi makes obvious the polymer layer as an adhesive layer and Okuyama discloses activating the polymer as well as the substrates.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized that depositing the polymer layer onto at least one of the activated surface of the piezoelectric substrate or a surface of the handling substrate comprises depositing the polymer layer directly on the handling substrate as suggested by Belhachemi and Okuyama in order to reduce makes it possible to avoid, or at least to reduce, the deformations of the piezoelectric substrate and the support substrate and to also achieve cleaning of the surfaces before the polymer bonding operations.
As to claim 5, Akiyama does not disclose further comprising treating the polymer layer to obtain a crosslinked polymer layer and bond the handling substrate to the piezoelectric substrate.
However, Belhachemi discloses and makes obvious further comprising treating the polymer layer to obtain a crosslinked polymer layer and bond the handling substrate to the piezoelectric substrate. See the translation, disclosing:
irradiating the assembled substrate with a luminous flux to polymerize the adhesive layer, said adhesive layer and the dielectric layer together forming the electrically insulating layer.
See later in the translation, disclosing:
Subsequently, the assembled substrate 5 is irradiated with a luminous flux 6 in order to polymerize the adhesive layer 2. The irradiation of the assembled substrate 5 is shown in FIG. 4.
The light source is preferably a laser.
The light radiation 5, or luminous flux, is preferably ultraviolet (UV) radiation. Depending on the composition of the adhesive layer 2, UV radiation with a wavelength between 320 nm (nanometers) and 365 nm will preferably be selected.
The irradiation is carried out by exposing the free face 31 of the piezoelectric substrate to the incident light radiation 6. Thus, the light radiation enters the assembled substrate 5 from the free face 31 of the piezoelectric substrate 3, passes through the piezoelectric substrate, passes through the dielectric layer 4, until reaching the adhesive layer 2, thereby causing the polymerization of said adhesive layer. The polymerization of the adhesive layer makes it possible to form a polymer layer 20 which ensures the mechanical cohesion of the assembled substrate, while keeping together the support substrate 1 and the piezoelectric substrate 3 which form the final substrate 7.
Irradiation of the assembled substrate 5 gives rise to a thermal process in which the piezoelectric layer 3, traversed by the radiation, can partly absorb the energy of the radiation and heat up. Excessive heating would be likely to destabilize the structure of the piezoelectric layer, which could lead to degradation of the physical and chemical properties of the piezoelectric layer. In addition, overheating would cause deformation of the piezoelectric layer and the support substrate due to their difference in coefficient of thermal expansion, resulting in a global deformation ("bow") of the assembled substrate and thus the resulting final substrate.
In order to avoid excessive heating of the piezoelectric layer 3, the irradiation is advantageously effected in a pulsed manner, that is to say by exposing the assembled substrate to a plurality of light ray pulses. Each pulse is performed during a given irradiation time, which may be equal or different from one pulse to the next. The pulses are spaced in time by a determined rest period during which the assembled substrate is not exposed to light rays.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized further comprising treating the polymer layer to obtain a crosslinked polymer layer and bond the handling substrate to the piezoelectric substrate as taught by Belhachemi by irradiating with a luminous flux in order to polymerize the adhesive layer because the polymerization of the adhesive layer makes it possible to form a polymer layer which ensures the mechanical cohesion of the assembled substrate.
As to claim 6, Akiyama discloses wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing an oxygen-based surface activation treatment creating pendant bonds on the activated surface of the piezoelectric substrate.
See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 7, Akiyama discloses wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing a treatment with ozone. See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 9, Akiyama discloses wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing a plasma treatment. See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 10, Akiyama discloses wherein providing the piezoelectric substrate comprises selecting the piezoelectric substrate to be a lithium tantalate substrate, a lithium niobate substrate, an aluminum nitride substrate, a lead zirconate titanate substrate, a langasite substrate, or a langatate substrate.
See the translation, which discloses that “An oxide single crystal such as lithium tantalate (LT) and lithium niobate (LN) is a typical piezoelectric material”
As to claim 11, Akiyama discloses or makes obvious further comprising thinning the piezoelectric substrate of the donor substrate after assembling the piezoelectric substrate on the handling substrate.
See the translation, which discloses that thinning of the oxide single crystal wafer is known:
For improving the temperature stability in the case where the oxide single crystal is used as a piezoelectric material, there is provided, for example, a method comprising steps of: laminating, with an oxide single-crystal wafer, a material having a thermal expansion coefficient smaller than that of the oxide single crystal, more specifically, a sapphire wafer; and thinning (e.g. grinding) the oxide single-crystal wafer side of the resulting laminate to a thickness of from several to tens of .Math.m to suppress the influence of thermal expansion of the oxide single crystal (Non-Patent Document 1).
It should be noted that Akiyama discloses thinning and grinding in the context of the prior art or background of the invention. In any event, these disclosed background techniques could be used with the other techniques disclosed in Akiyama.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized further comprising thinning the piezoelectric substrate of the donor substrate after assembling the piezoelectric substrate on the handling substrate in order to suppress the influence of thermal expansion of the oxide single crystal as taught in the background section of Akiyama.
As to claim 13, Akiyama discloses further comprising selecting the handling substrate to comprise a silicon-based substrate. See the translation, disclosing “Examples of the support wafer include a sapphire wafer, a silicon wafer, a silicon wafer with an oxide film, and a glass wafer.”
As to claim 14, Akiyama discloses wherein performing the treatment with ozone comprises performing a wet treatment. See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 15, Akiyama discloses wherein performing the treatment with ozone comprises performing a UV assisted treatment. See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 16, Akiyama discloses wherein performing the plasma treatment comprises performing an oxygen-based plasma treatment. See the translation, disclosing:
Examples of the surface activation treatment include ozone water treatment, UV ozone treatment, ion beam treatment, and plasma treatment. When the ozone water treatment is selected, the surface can be activated with active ozone, for example, by introducing an ozone gas into pure water to obtain ozone water, and immersing the wafer in the resulting ozone water. When UV ozone treatment is selected, the surface can be activated, for example, by retaining the wafer in an atmosphere in which active ozone has been generated by irradiating the air or an oxygen gas with short-wavelength UV light (having, for example, a wavelength of about 195 nm). When ion beam treatment is selected, the surface can be activated, for example, by applying an ion beam such as Ar to the wafer surface in high vacuum (e.g. less than 1×10.sup.-5 Pa) to allow highly active dangling bonds to be exposed on the surface. When plasma treatment is selected, the surface is treated with plasma, for example, by exposing the wafer placed in a vacuum chamber to a plasma gas under reduced pressure (for example, from 0.2 to 1.0 mTorr) for about 5 to 60 seconds. As the plasma gas, an oxygen gas is used for oxidizing the surface, while a hydrogen gas, a nitrogen gas, an argon gas, or a mixture thereof may be used for not oxidizing the surface. When the wafer surface is treated with plasma, organic matters thereon are removed by oxidation and further, the wafer surface is activated because of the increased number of OH groups on the surface.
As to claim 17, Akiyama discloses wherein thinning the piezoelectric substrate of the donor substrate comprises grinding the piezoelectric substrate.
See the translation, which discloses that thinning of the oxide single crystal wafer is known:
For improving the temperature stability in the case where the oxide single crystal is used as a piezoelectric material, there is provided, for example, a method comprising steps of: laminating, with an oxide single-crystal wafer, a material having a thermal expansion coefficient smaller than that of the oxide single crystal, more specifically, a sapphire wafer; and thinning (e.g. grinding) the oxide single-crystal wafer side of the resulting laminate to a thickness of from several to tens of .Math.m to suppress the influence of thermal expansion of the oxide single crystal (Non-Patent Document 1).
It should be noted that Akiyama discloses thinning and grinding in the context of the prior art or background of the invention. In any event, these disclosed background techniques could be used with the other techniques disclosed in Akiyama.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized wherein thinning the piezoelectric substrate of the donor substrate comprises grinding the piezoelectric substrate in order to suppress the influence of thermal expansion of the oxide single crystal as taught in the background section of Akiyama.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Akiyama (EP 3306644 A1), Belhachemi (WO 2019186053 A1) and Okuyama (WO 2015008658 A1) as applied to claims 1-2,4-7, 9-11 and 13-17 above, and further in view of Reinhardt (FR 2988538 A1).
As to claim 8, Akiyama, Belhachemi and Okuyama do not disclose wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing a treatment with a solution based on hydrogen peroxide.
However, Reinhardt discloses and makes obvious wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing a treatment with a solution based on hydrogen peroxide in methods that can utilize a donor substrate made of piezoelectric material. See the translation, disclosing:
According to a variant of the invention, the method comprises the production of said piezoelectric transducer on a host substrate and is characterized in that it comprises the following steps: - the production of a first part of a cavity resonating on the surface a donor substrate made of piezoelectric material; - Making a second portion of said resonant cavity on the surface of a host substrate; gluing the first and second parts of the resonant cavity so as to define a single resonant cavity at the frequency Fi; an operation of delimiting a layer of material in said donor substrate so as to obtain said layer; piezoelectric material; the production of at least one series of electrodes on the surface of said separated piezoelectric layer. According to a variant of the invention, the first and second parts being half-cavities, each of these half-cavities comprises the deposition of a layer of thickness equal to n / i / 4 with non-zero integer. According to a variant of the invention, the operation of delimiting a layer of material in said donor substrate comprises: producing a zone weakened in said substrate so as to delimit in said substrate, said piezoelectric layer; Separating said piezoelectric layer from said donor substrate. According to a variant of the invention, the realization of a weakened zone in said substrate is carried out by implantation.
See later in the translation, disclosing the use of hydrogen peroxide treatments:
According to a first step illustrated in FIG. 14a, starting from a substrate S, made of boron-doped silicon (resistivity of 10 to 15 mΩ.cm) that is cleaned by a bath RCA type (mixture of deionized water, hydrochloric acid and hydrogen peroxide), followed by a deoxidation operation in a dilute HF solution.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the filing of the invention to have utilized wherein performing the surface activation treatment on the surface of the piezoelectric substrate to form the activated surface of the piezoelectric substrate comprises performing a treatment with a solution based on hydrogen peroxide as taught by Reinhardt in order to ensure proper cleaning of the surfaces of the substrates.
Conclusion
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/GEORGE R KOCH/Primary Examiner, Art Unit 1745
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