DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
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.
Claim(s)1-17, is/are rejected under 35 U.S.C. 103 as being unpatentable over U. S. Patent Application Publication No. 2014/0356770 (Hayashi) in view of U. S. Patent Application Publication No. 2013/0078555 (hereinafter referred to as Orihara).
Hayashi, in the abstract, in [0005], [0020]-[0034], discloses a mask blank that has a stacked layer on the substrate that includes a pattern forming film layer that comprises chromium and nitrogen (CrN layer, absorber layer that has a two layered stack). Hayashi, in [0041], discloses that the surface roughness (RMS) is at most 0.5nm i.e., less than 0.5nm which inherently includes less than 0.5nm average/mean surface roughness (claimed arithmetic mean). Hayashi, in [0063]-[0064] uses a substrate for the mask blank of 152mm square and Hayashi, in [0087], discloses that the absorber layer formed on the mask blank is of a smooth surface i.e., the entire regions that constitute the 152mm square and includes the central region and the peripheral regions adjacent and non-overlapping to the central region, and Hayashi, in [0117], discloses that the surface of the absorber layer (the entire surface of the absorber film on the mask blank) formed on the mask blank most preferably has surface roughness at most 0.3nm and includes the claimed 1-µm square central region of the film with respect to the center of the substrate. Hayashi, in [0101]-[0105], and [0136], and [0193] discloses that the absorber layer is patterned using a resist pattern as the mask overlying the absorber layer (pattern forming thin film) and the exposed absorber layer is removed by dry etching so as to form an absorber pattern (transfer pattern), and the absorber pattern (transfer pattern) is used for patterning the underlying low reflective layer by using the absorber pattern as the mask (claimed transferring the pattern to the phase shift film-low reflective layer) such that portions of the low reflective layer (exposed) are removed by patterning (etching, claimed dry etching) to form the mask (photomask) (claims 1-2, 14-15). Hayashi, in [0084], [0117], discloses that the root-mean-square roughness of the absorber layer (CrN containing film) is at most 0.3nm (claim 4). Hayashi, in [0065], [0131]-[0132], [0156], discloses that the absorber layer is subjected to inspection (the entire surface includes the claimed central region or inner region of the claimed size of the blank substrate) for defect inspection at a wavelength of about 193nm and discloses that no defects are present i.e., defects less than 100, and if a defect (1) is present on the surface of the film, the height of the convex defect is not more than 2nm (less than 10nm) (claim 5). Hayashi, in [0020], and [0023], discloses that the film formed on the mask blank substrate includes chromium and nitrogen, and Hayashi, in [0085], discloses that the nitrogen content in the CrN film is greater than 3 at%, and Hayashi, in [0084], discloses that the chromium content in the CrN film is greater than 40 at% wherein the CrN layer can be a single layer (lower layer film or part of a stack of layers) (claims 6-7). Hayashi, in [0035], discloses forming protective film on the two-layer structure (absorber layer) wherein the protective film includes silicon ([0039]) and oxygen ([0034]-[0035]), and Hayashi, in [0193], discloses that the layer formed on the absorber layer is a hard mask layer i.e., the hard mask layer can be formed on the absorber multilayer (CrON/CrN) (claims 8, 10). Hayashi, in [0023], discloses forming a Cr film as the absorber layer and Hayashi, in [0031], discloses that the Cr film is a CrN film, and Hayashi, in [0034], discloses that the CrN upper layer is a two-layer structure that includes forming a CrON layer above the CrN layer i.e., the claimed one additional layer containing chromium and nitrogen formed on the underlying CrN based layer includes oxygen (claims 9, and 17). Hayashi, in the abstract, [0019], [0020], [0023], [0029]-[0030], discloses that overlying the surface of the mask blank substrate and underlying the absorber layer (i.e., between the substrate and the absorber layer, the absorber layer is the claimed pattern-forming thin film) is a reflective layer (claimed phase shift film) that causes the light reflected to have a phase difference of about 180° +/- 10° with respect to the exposure light, and Hayashi, in [0067], discloses that the reflective layer is a Mo/Si reflective film and is the same composition as the claimed phase shift film and inherently transmits light is the claimed amount (claims 11-12). Hayashi, in [0007], [0009], and [0051], discloses that the transferring of a pattern to the absorber layer results in the formation of a mask with a transfer pattern (mask pattern, claimed transfer mask) that is used as a mask during exposure of a resist film on a substrate (semiconductor substrate) to transfer the mask pattern onto the resist film (photolithography) (claim 16).
The difference between the claims and Hayashi is that Hayashi does not disclose the claimed ratio of the maximum height to mean roughness or the maximum height value recited in claim 3. Hayashi does not disclose the phase shift transmittance at the claimed wavelength. Hayashi does not disclose the claimed optical density of the stack layers recited in claim 13.
Orihara, in [0240]-[0243], discloses that the CrN layer formed on the mask substrate has a roughness of about 0.1nm (root mean squared roughness which is greater than the average roughness) and has a maximum height of about 0.95nm (claimed maximum height Sz) such that the ratio of the maximum height to the roughness is about 9.5 and is the same as the claimed ratio. Orihara discloses in [0102], the use of a phase shift film on the mask blank at the claimed exposure wavelength (ArF excimer laser, 193nm). Orihara, in [0102], and [0282], discloses that the stack of layers (absorber layer and phase shift film) has the same claimed optical density (about 3.0) at the claimed wavelength (ArF excimer light).
Therefore, it would be obvious to a skilled artisan to modify Hayashi by employing the height to roughness ratio taught by Orihara because Hayashi teaches a surface roughness in the same claimed range and Orihara teaches in [0216] that keeping the maximum height to a value as low as 0.6nm enables a reduction in the variation of the surface roughness of the surface and Hayashi teaches in [0116], [0117], that the surface roughness is kept at such a low value so as to enable a smooth surface of the film on the mask blank. It would be obvious to a skilled artisan to modify Hayashi by using the mask in the claimed exposure wavelength as taught by Orihara because Hayashi does not prohibit the use of the claimed wavelength, and Hayashi teaches that the film underlying the absorber layer is of the same material and causes phase shift in the reflected light and will inherently possess the claimed transmittance in the claimed wavelength. It would be obvious to a skilled artisan to modify Hayashi by using the claimed optical density as taught by Orihara because Hayashi teaches the same claimed layered stack taught by Orihara, and Hayashi teaches that the mask blank substrate includes a low reflective layer (claimed phase shifting film) and overlying absorber layer that has the same claimed compositional components and stack (CrON layer formed atop the CrN) and will inherently and necessarily possess the claimed optical density at the claimed wavelength.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Daborah Chacko-Davis whose telephone number is (571) 272-1380. The examiner can normally be reached on 9:30AM-6:00PM EST Mon-Fri. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Mark F. Huff can be reached on (571) 272-1385. The fax phone number for the organization where this application or proceeding is assigned is 571-272-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/DABORAH CHACKO-DAVIS/Primary Examiner, Art Unit 1737 March 19, 2026.
Prosecution Insights