Attorney’s Docket Number: KLA-086 (P6266)
Filing Date: 12/20/2023
Claimed Domestic Priority Date: 1/12/2023 (PRO 63/438,788)
Applicant(s): Butaeva et al.
Examiner: Rianna B. Greer
DETAILED ACTION
This Office Action respond to the application filed on 12/20/2023.
Remarks
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . The application serial no. 18/391,595 filed on 12/20/2023 has been entered. Pending in this Office Action are claims 1-20.
Specification
2. The disclosure is objected to because of the following informalities:
- In Par. [0054], “pure boron coating 180B is then formed by depositing an amorphous layer of pure boron on the exposed backside surface using a low-temperature boron deposition process (block 110B).” should read --Pure boron coating 180B is then formed by depositing an amorphous layer of pure boron on the exposed backside surface using a low-temperature boron deposition process (block 110B).--
- In Par. [0058], “silicon layer 165C is formed after the boron deposition by way of an anneal step that causes boron atoms to heavily p-doped a portion of epitaxial silicon located adjacent to backside surface 162C.” should read -- silicon layer 165C is formed after the boron deposition by way of an anneal step that causes boron atoms to heavily p-dope
- In Par. [0061], “It is also possible that in some embodiments represented by 5B, the interface of the protection layer and fluoride layer may have a few layers of mixed oxy-fluoride or nitro-fluorides type compounds due to intermixing of the oxide or nitride and fluoride layers during the fluorination process.” should read --It is also possible that in some embodiments represented by 5C, the interface of the protection layer and fluoride layer may have a few layers of mixed oxy-fluoride or nitro-fluorides type compounds due to intermixing of the oxide or nitride and fluoride layers during the fluorination process--
- In Par. [0062], “silicon layer 165D is formed after the boron deposition by way of an anneal step that causes boron atoms to heavily p-doped a portion of epitaxial silicon located adjacent to backside surface 162D.” should read -- silicon layer 165D is formed after the boron deposition by way of an anneal step that causes boron atoms to heavily p-dope
- In Par. [0067], “To perform the fluorination process, a gas delivery controller 621E controls the flow of plasma gas and fluorine containing gas into processing region 612E and through one or more apertures formed in an electrode 631F, and plasma controller 635F biases electrode 631F (e.g., using a plasma voltage VP) with respect to stage 613F, which acts as a 2nd electrode, to generate a capacitively coupled plasm 637F over membrane 160F.” should read -- To perform the fluorination process, a gas delivery controller 621E controls the flow of plasma gas and fluorine containing gas into processing region 612E and through one or more apertures formed in an electrode 631F, and plasma controller 635F biases electrode 631F (e.g., using a plasma voltage VP) with respect to stage 613F, which acts as a 2nd electrode, to generate a capacitively coupled plasma 637F over membrane 160F.--
Appropriate corrections are required.
Claim Rejections - 35 USC § 103
3. Claims 1-5, 7-13, and 17-20 are rejected under 35 U.S.C. 103 as being unpatentable over Chern (US2013/0264481) in view of Wakatsuki (US2019/0279932).
4. Regarding Claim 1, Chern (see, e.g., Fig. 3G) shows most aspects of the instant invention including a back-illuminated image sensor configured to sense at least one of deep ultraviolet (DUV) radiation and vacuum ultraviolet (VUV) radiation (e.g., Par. [0020]: back-illuminated image sensor with operation for DUV and VUV radiation), the image sensor comprising:
- a semiconductor membrane (e.g., Fig. 3G and Par. [0023]: semiconductor membrane comprising 301A, 302) having a frontside surface and an opposing backside surface
- front-end circuit structures (e.g., front-side circuit elements 305) disposed on the frontside surface
- a pure boron coating (e.g., pure boron layer 306) disposed on the backside surface
- a protective layer disposed on the pure boron coating (e.g., Par. [0054]: other layers deposited on the boron layer may include a protective layer)
- a fluoride-based anti-reflection coating (e.g., Par. [0054]: other layers deposited on the boron layer may include an anti-reflection coating comprising, e.g., magnesium fluoride and lithium fluoride)
- wherein the protective layer has a thickness in the range of 0.5 nm and 10 nm (e.g., Par. [0054]: protective layer comprises a thin layer of a refractory metal with a thickness between approximately 1 nm and approximately 10 nm)
5. However, while Chern discloses that both the protective layer and the anti-reflection coating are disposed on the pure boron layer 306, they are silent about a particular arrangement wherein the anti-reflection coating is disposed on the protective layer as claimed. Furthermore, while Chern discloses that the protective layer comprises a thin layer of a refractory metal, they are silent about the protective layer comprising one of an oxide film and a nitride film as claimed.
6. Wakatsuki (see, e.g., Pars. [0041], [0044]), on the other hand and in the related field of mitigating fluoride migration, teaches a semiconductor structure having a crystal separation layer 18 between a fluoride-containing layer 19 and remaining layers of the semiconductor structure, wherein layer 18 is preferably not a single metal film but a metal oxide film or a metal nitride film having a thickness in the range of 0.5 nm and 2 nm, to implement an intervening layer of more thermally stable material for preventing fluoride migration from the fluoride-containing layer into the remaining layers and to mitigate the deterioration of said remaining layers.
7. Accordingly, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have the protective layer comprising one of an oxide film and a nitride film instead and the anti-reflection coating being disposed on the protective layer in the structure of Chern, as taught by Wakatsuki, to implement an intervening layer of more thermally stable material for preventing fluoride migration from the fluoride-containing anti-reflection coating into the remaining layers and to mitigate the deterioration of said remaining layers.
8. Regarding Claim 2, Chern shows that the semiconductor membrane comprises an epitaxial layer having a thickness in the range of 10 μm to 100 μm (see, e.g., Par. [0037]: 20 μm to 40 μm).
9. Regarding Claim 3, Chern shows that the pure boron coating has a thickness in the range of 2 nm to 20 nm (see, e.g., Par. [0020]: between about 2 nm and about 20 nm thick).
10. Regarding Claim 4, Wakatsuki teaches that the protective layer comprises one of Al2O3, MgO, La2O3, Li2O, CaO, BeO, HfO2, AlN, Li3N, LaN, Mg3N2, HfN and Ca3N2 (see, e.g., Par. [0031]: the crystal separation layer 18 is, for example, a metal oxide film such as an Al2O3 film, or an AlN film).
11. Regarding Claim 5, Wakatsuki teaches that the protective layer comprises one of Al2O3 and AlN (see, e.g., Par. [0031]: the crystal separation layer 18 is, for example, a metal oxide film such as an Al2O3 film, or an AlN film) and has a thickness in the range of 0.5 nm and 5 nm (see, e.g., Par. [0044]: the thickness of the crystal separation layer 18 is preferably between 0.5 nm and 2.0 nm).
12. Regarding Claim 7, Chern (see, e.g., Figs. 1-2, 3A-3G) shows most aspects of the instant invention including a method of fabricating an image sensor configured to sense at least one of deep ultraviolet (DUV) radiation and vacuum ultraviolet (VUV) radiation, the method comprising:
- forming front-end circuit structures on a first surface of a semiconductor membrane (e.g., Fig. 3B)
- forming a pure boron coating on a second surface of the semiconductor membrane (e.g., Fig. 3E)
- forming a protective layer on the pure boron coating (e.g., Par. [0054]: other layers deposited on the boron layer may include a protective layer)
- forming a fluoride-based anti-reflection coating (e.g., Par. [0054]: other layers deposited on the boron layer may include an anti-reflection coating comprising, e.g., magnesium fluoride and lithium fluoride)
- wherein the protective layer has a thickness in the range of 0.5 nm and 50 nm (e.g., Par. [0054]: protective layer comprises a thin layer of a refractory metal with a thickness between approximately 1 nm and approximately 10 nm)
13. However, while Chern discloses that both the protective layer and the anti-reflection coating are formed on the pure boron layer 306, they are silent about a particular arrangement wherein the anti-reflection coating is formed on the protective layer as claimed. Furthermore, while Chern discloses that the protective layer comprises a thin layer of a refractory metal, they are silent about the protective layer comprising one of an oxide film and a nitride film as claimed.
14. Wakatsuki (see, e.g., Pars. [0041], [0044]), on the other hand and in the related field of mitigating fluoride migration, teaches the formation of a crystal separation layer 18 between a fluoride-containing layer 19 and remaining layers of the semiconductor structure, wherein layer 18 is preferably not a single metal film but a metal oxide film or a metal nitride film having a thickness in the range of 0.5 nm and 2 nm, to implement an intervening layer of more thermally stable material for preventing fluoride migration from the fluoride-containing layer into the remaining layers and to mitigate the deterioration of said remaining layers.
15. Accordingly, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have the protective layer comprising one of an oxide film and a nitride film instead and the anti-reflection coating formed on the protective layer in the method of Chern, as taught by Wakatsuki, to implement an intervening layer of more thermally stable material for preventing fluoride migration from the fluoride-containing anti-reflection coating into the remaining layers and to mitigate the deterioration of said remaining layers.
16. Regarding Claim 8, Chern shows that the method of forming said pure boron coating comprises depositing one or more layers of amorphous boron on the second surface until the pure boron coating has a total thickness in the range of 2 nm to 20 nm (see, e.g., Par. [0020]: between about 2 nm and about 20 nm thick).
17. Regarding Claim 9, Chern shows that the method of forming said pure boron coating comprises utilizing a high temperature deposition process (see, e.g., Fig. 1 and Par. [0042]: this deposition can be performed at a temperature of about 700-800 °C), and wherein the method further comprises forming metal interconnects over the front-end circuit structures after forming said pure boron coating (see, e.g., Fig. 1 and Par. [0042]: in step 111, an amorphous layer of pure boron is deposited on the back-side of the back-side surface, followed by Par. [0046]: in step 115, interconnects on the front surface can be fabricated, and these interconnects may be formed by Al, Cu, or another metal).
18. Regarding Claim 10, Chern shows that the method further comprises forming metal interconnects over the front-end circuit structures before forming said pure boron coating (see, e.g., Fig. 2 and Par. [0048]: the circuit elements can be created in step 201, followed by Par. [0053]: in step 211, boron is deposited on the back-side surface of the wafer), and wherein forming said pure boron coating comprises utilizing a low temperature deposition process (see, e.g., Fig. 2 and Par. [0053]: this deposition can be done at a temperature of about 400-450 °C).
19. Regarding Claim 11, Wakatsuki teaches that the method of forming the protective layer comprises depositing at least one of Al2O3, MgO, La2O3, Li2O, CaO, BeO, HfO2, AlN, Li3N, LaN, Mg3N2, HfN and Ca3N2 on an upper surface of the pure boron coating (see, e.g., Par. [0031]: the crystal separation layer 18 is, for example, a metal oxide film such as an Al2O3 film, or an AlN film).
20. Regarding Claim 12, Wakatsuki teaches that forming the protection layer comprises depositing said one of said oxide film and said nitride film such that said thickness is in the range of 0.5 nm to 10 nm (see, e.g., Pars. [0041], [0044]: layer 18 is preferably not a single metal film but a metal oxide film or a metal nitride film having a thickness in the range of 0.5 nm and 2 nm), and Chern shows that forming the fluoride-based anti-reflective coating comprises depositing one or more fluoride-based materials onto the protection layer (e.g., Par. [0054]: the anti-reflection coating comprises, e.g., magnesium fluoride and lithium fluoride).
21. Regarding Claim 13, Chern shows that depositing one or more fluoride-based materials comprises depositing at least one of AlF3, MgF2, CaF2, LaF3, LiF and HfF4 (e.g., Par. [0054]: the anti-reflection coating comprises, e.g., magnesium fluoride and lithium fluoride).
22. Regarding Claim 17, Chern shows that said semiconductor membrane includes a p-doped epitaxial silicon layer (see, e.g., Par. [0037]: the epi layer is doped with p-type dopants), disposed on a silicon substrate, and wherein the method further comprises back-thinning at least a portion of the silicon substrate to expose at least a portion of the p-doped epitaxial silicon layer, where said exposed portion of the p-doped epitaxial silicon layer forms the second surface of said semiconductor membrane (see, e.g., Figs. 1-2, 3A-3G, and Par. [0038]: in step 103, the active sensor areas or even the whole wafer may be thinned from the backside).
23. Regarding Claim 18, Chern (see, e.g., Figs. 4A-4G) shows that said semiconductor membrane includes a p-doped epitaxial silicon layer formed on a top silicon substrate of a silicon-on-insulator (SOI) structure (see, e.g., Fig. 4A and Par. [0058]: the substrate is an SOI (silicon-on-insulator) wafer), the p-doped epitaxial silicon layer having a first p-type doping concentration and the top silicon substrate having a second p-type doping concentration that is greater than the first p-type doping concentration (see, e.g., Par. [0058]: substrate 401 is a p+ substrate, and epi layer 402 is a p- epi layer), wherein forming the front-end circuit structures (e.g., front-side circuit elements 403) on the first surface of the semiconductor membrane comprises forming the front-end circuit structures on the p-doped epitaxial silicon layer (e.g., Fig. 4B), and wherein forming the pure boron coating (e.g., pure boron layer 406) on the second surface of the semiconductor membrane comprises: removing at least a portion of a handle substrate and oxide layer of the SOI structure to expose one or more surface portions of the top silicon substrate (e.g., Figs. 4D-4E); and forming the pure boron coating on the exposed surface portions (e.g., Fig. 4F).
24. Regarding Claim 19, Chern shows that the method further comprises forming through-silicon vias in the semiconductor membrane before forming the pure boron coating (see, e.g., Fig. 4B).
25. Regarding Claim 20, Chern (see, e.g., Fig. 11) shows most aspects of the instant invention including an inspection system comprising:
- an illumination source (e.g., illumination source 1102)
- a set of optics (e.g., optics 1103) including an objective lens (e.g., objective lens 1105) configured to direct and focus incident light from the illumination source onto a sample (e.g., sample 1108) and to collect, direct, and focus reflected/scattered light from the sample onto a detector assembly (e.g., detector assembly 1104), wherein the detector includes one or more image sensors configured to sense at least one of deep ultraviolet (DUV) radiation and vacuum ultraviolet (VUV) radiation (e.g., Fig. 3G and Par. [0020]: back-illuminated image sensor with operation for DUV and VUV radiation), wherein each said image sensor comprises a semiconductor membrane (e.g., Fig. 3G and Par. [0023]: semiconductor membrane comprising 301A, 302), circuit elements (e.g., front-side circuit elements 305) formed on a first surface of the semiconductor membrane, at least one pure boron layer (e.g., pure boron layer 306) formed on a second surface of the semiconductor membrane, a protective layer formed on the pure boron layer (e.g., Par. [0054]: other layers deposited on the boron layer may include a protective layer), and a fluoride-based antireflection coating disposed over the protective layer (e.g., Par. [0054]: other layers deposited on the boron layer may include an anti-reflection coating comprising, e.g., magnesium fluoride and lithium fluoride), and wherein the protective layer has a thickness in the range of 0.5 nm and 10 nm (e.g., Par. [0054]: protective layer comprises a thin layer of a refractory metal with a thickness between approximately 1 nm and approximately 10 nm)
26. However, while Chern discloses that both the protective layer and the anti-reflection coating are disposed on the pure boron layer 306, they are silent about a particular arrangement wherein the anti-reflection coating is disposed on the protective layer as claimed. Furthermore, while Chern discloses that the protective layer comprises a thin layer of a refractory metal, they are silent about the protective layer comprising one of an oxide film and a nitride film as claimed.
27. Wakatsuki (see, e.g., Pars. [0041], [0044]), on the other hand and in the related field of mitigating fluoride migration, teaches a semiconductor structure having a crystal separation layer 18 between a fluoride-containing layer 19 and remaining layers of the semiconductor structure, wherein layer 18 is preferably not a single metal film but a metal oxide film or a metal nitride film having a thickness in the range of 0.5 nm and 2 nm, to implement an intervening layer of more thermally stable material for preventing fluoride migration from the fluoride-containing layer into the remaining layers and to mitigate the deterioration of said remaining layers. See comments stated above in Par. 7 with regards to Claim 1, which are considered repeated here.
28. Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Chern (US2013/0264481) in view of Wakatsuki (US2019/0279932) and in further view of Muramatsu (US2015/0200216).
29. Regarding Claim 6, while Chern shows that the fluoride-based antireflection coating comprises one of AlF3, MgF2, CaF2, LaF3, LiF, and HfF4 (e.g., Par. [0054]: other layers deposited on the boron layer may include an anti-reflection coating comprising, e.g., magnesium fluoride and lithium fluoride), they are silent about the fluoride-based antireflection coating having a thickness in the range of 2 nm and 40 nm. Therefore, Chern in view of Wakatsuki does not explicitly show the fluoride-based antireflection coating with the thickness in range as claimed. Muramatsu (see, e.g., Par. [0031]), on the other hand and in the same field of endeavor, teaches that anti-reflection layers for image sensors configured to sense DUV and VUV radiation are preferably thin (between about 10 nm and 20 nm thick) since limiting layer thickness to one or two atomic layers has the advantage of maintaining consistent reflectivity (and therefore consistent sensitivity) between image sensors.
30. Accordingly, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have with the thickness of the fluoride-based antireflection coating in the range of 2 nm and 40 nm in the structure of Chern in view of Wakatsuki, as taught by Muramatsu, because antireflection coatings having a thickness in the range of 2 nm and 40 nm maintain consistent sensitivity between image sensors.
31. Claims 14-16 are rejected under 35 U.S.C. 103 as being unpatentable over Chern (US2013/0264481) in view of Wakatsuki (US2019/0279932) and in further view of Lange (US2025/0230535).
32. Regarding Claim 14, while Wakatsuki teaches that forming the protection layer comprises depositing said one of said oxide film and said nitride film (see, e.g., Par. [0031]: the crystal separation layer 18 is, for example, a metal oxide film such as an Al2O3 film, or an AlN film), they are silent about the protection layer having a total thickness in the range of 10 nm to 50 nm. Furthermore, they are also silent about how forming the fluoride-based anti-reflective coating comprises utilizing a fluorination process to convert an upper region of the protection layer into the fluoride-based anti-reflection coating. Lange (see, e.g., Fig. 1 and Par. [0022]), on the other hand and in the same field of endeavor, teaches the fluorination of a deposited oxide layer to form an oxyfluoride layer as an anti-reflective coating for optical elements tailored for use in the VUV wavelength range (see, e.g., Par. [0004]) and to introduce oxide layers in such optical elements reduces degradation at high radiation intensities and extends the service lives of such optical elements. The formation of an oxyfluoride layer is consistent with the applicant’s specification, which discloses the possibility that the interface of the protection layer and fluoride-based anti-reflection coating may have an oxyfluoride layer due to intermixing of the oxide and fluoride layers during the fluoride deposition process in Par. [0057]. Lange (see, e.g., Pars. [0045], [0075]) also discloses that the thickness of the oxide layer deposited is variable; for example, if the oxide layer has a small thickness (in the range of 5 nm to 10 nm), then the oxide layer is completely converted into a fluoride layer, while if the oxide layer has a greater thickness (above 10 nm), only a volume area of the oxide layer adjacent to the surface is converted into the fluoride layer and an oxyfluoride layer is created. Therefore, Lange implicitly recognizes the thickness of the deposited oxide layer as a result-effective variable. Accordingly, the specific thickness of the protection layer claimed by the applicant, i.e. a thickness in the range of 10 nm to 50 nm, is only considered to be the “optimum” oxide layer thickness disclosed by Lange that a person having ordinary skill in the art would have been able to obtain using routine experimentation based on the degree of fluorination achieved by irradiation time, and since neither non-obvious nor unexpected results, i.e. results which are different in kind and not in degree from the results of the prior art, will be obtained so long as an oxide layer is fluorinated to create the oxyfluoride layer.
33. Accordingly, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to form the protection layer comprising depositing said one of said oxide film and said nitride film with a total thickness in the range of 10 nm to 50 nm, and wherein forming the fluoride-based anti-reflective coating comprises utilizing a fluorination process to convert an upper region of the protection layer into the fluoride-based anti-reflection coating in the method of Chern in view of Wakatsuki, as taught by Lange, to introduce oxide layers in optical elements tailored for use in the VUV wavelength range and to reduce degradation at high radiation intensities and extend the service lives of such optical elements.
34. Regarding Claim 15, Lange teaches that utilizing said fluorination process comprises exposing the protection layer to at least one fluorine-containing gas (see, e.g., Par. [0024]: the fluorination agent can be a gas from which a reactive fluorine species is generated, and this reactive fluorine species can chemically convert the oxide into a fluoride, at least in the region of the surface of the oxide layer).
35. Regarding Claim 16, Lange teaches that utilizing the fluorination process comprises using a plasma process (see, e.g., Par. [0024]: the fluorination agent can be a gas which photodissociates as a consequence of irradiation with UV/VUV radiation and in the process forms a molecular and/or atomic, especially also ionized and/or excited, reactive fluorine species).
Conclusion
36. Any inquiry concerning this communication or earlier communications from the examiner should be directed to Rianna B. Greer whose telephone number is (571) 272-7985. The examiner can normally be reached Monday - Friday, 8 AM - 6 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Wael Fahmy can be reached at (571) 272-1705. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/R.B.G./Examiner, Art Unit 2814
/WAEL M FAHMY/Supervisory Patent Examiner, Art Unit 2814