DETAILED ACTION
This action is responsive to the application filed January 29, 2025. Claims 1-20 are pending. Claims 1, 10, and 20 are independent.
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 .
Information Disclosure Statement
Acknowledgment is made of applicant’s Information Disclosure Statements (IDS) filed on February 4, 2025, April 21, 2026, and August 11, 2026. These IDS have been considered.
Claim Objections
Claims 6, 7, 14, and 15 are objected to because of the following informalities:
Each of the claims uses the grammatically incorrect phrase "the another" or "the another one". The correct phrasing is either "the other" or "another" (without the definite article). Appropriate correction is required.
Claim Rejections - 35 USC § 112 – Written Description
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claims 6-8, and 14-16 are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Regarding claims 6, 8, 14, and 16, the claims recite, in relevant part:
Claim 6: “determining whether the partial read threshold calibration provides sufficiently good calibration of a read threshold that is shared with the one of the plurality of entangled pages; and in response to determining whether the partial read threshold calibration provides sufficiently good calibration…”
Claim 8 (depending from claim 6): “in response to determining that the partial read threshold calibration does not provide sufficiently good calibration…”
Claim 14: parallel language to claim 6 (“sufficiently good calibration of a read threshold that is shared with the page of data”)
Claim 16 (depending from claim 14): parallel language to claim 8
The only disclosure directed to the determination appears in paragraphs 80 - 81: "In another embodiment, an indication of BER can be read after the calibration of Page4 to see if Page5 can now be read successfully or whether the calibration of Page6 is required before reading Page5 again.", "the controller 102 determines if there is an indication that partial read threshold correction is sufficient (1730) (e.g., if the partial read threshold calibration calibrates a read threshold that is shared with Page5). If partial read threshold correction is not sufficient, the read thresholds of Page6… are also calibrated (1740)… However, if partial read threshold correction is sufficient, the relevant read thresholds to Page5 are extracted without additional calibration (1760), and calibration of remaining Page5 read thresholds are slated to a background operation time (1770)."
This disclosure is limited to two vague examples: (1) reading "an indication of BER" to see whether the page "can now be read successfully," and (2) determining sufficiency based solely on whether a shared threshold has been calibrated. No objective metric, threshold value, algorithm, or decision criterion is provided that defines the boundary of "sufficiently good." The specification does not describe how a person of ordinary skill would determine, across the range of possible BER conditions, logical mappings, or entanglement configurations, whether a partial calibration meets the claimed "sufficiently good" standard.
Because the claim language employs a relative, subjective term whose scope is not reasonably conveyed by the limited examples in the specification, the disclosure fails to show that the inventors had possession of the full breadth of the claimed invention.
Claims 7 and 15 depend from claims 6 and 14 respectively and do not cure the deficiency. Therefore, they are likewise rejected for the same reasons set forth.
Claim Rejections - 35 USC § 112 - Indefiniteness
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.
Claims 6-8, and 14-16 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.
Regarding claims 6, 8, 14, and 16, each of these claims recites a determination of whether a partial read threshold calibration provides (or does not provide) "sufficiently good calibration" of a shared read threshold.
The term "sufficiently good" is a relative term that renders the claims indefinite. The specification does not provide an objective standard or working definition by which a person of ordinary skill in the art would be able to determine the metes and bounds of the claim with reasonable certainty.
The only guidance in the specification appears in paragraphs 80-81, which refer to reading "an indication of BER" to see whether a page “can now be read successfully” or determining sufficiency based on whether a shared threshold has been calibrated. These limited examples do not supply a clear, objective criterion (e.g., a BER threshold, syndrome-weight threshold, successful ECC decode condition, or other measurable metric) that defines when a calibration is "sufficiently good." As a result, the claims are indefinite.
Claims 7 and 15 depend from claims 6 and 14 respectively and do not cure the deficiency. Therefore, they are likewise rejected for the same reasons set forth.
As per MPEP § 2173.06, since claims 6-8 and 14-16 are rejected under 35 U.S.C. § 112(a) as failing to comply with the written description requirement and under 35 U.S.C § 112(b) as being indefinite for the reasons set forth above concerning the term "sufficiently good calibration", prior art will not be applied to these claims at this time because the metes and bounds cannot be reasonably determined. Should Applicant amend these claims to overcome the rejections under 35 U.S.C. § 112, further consideration of the prior art will be made.
Regarding claim 14, the claim recites, in relevant part: "in response to determining whether the partial read threshold calibration calibrates a read threshold that is shared with the page of data, using the calibrated read threshold of the another page of data as a calibrated read threshold of the page of data."
The use of the word "whether" renders the "in response to" clause logically defective. A determination of "whether" a condition is true always yields a result (true or false); the clause therefore fails to establish a conditional trigger for the subsequent "using" step. The claim language does not make clear under what circumstances the calibrated threshold is actually used.
By contrast, the parallel language in claim 6 properly conditions the "using" step on a determination that the partial calibration does provide sufficiently good calibration. The inconsistent and logically incomplete phrasing in claim 14 creates ambiguity as to the scope of the claim and renders it indefinite. See MPEP § 2173.05(e).
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.
Claims 1-2, 4-5, 9-13, and 17-20 are rejected under 35 U.S.C. 103 as being unpatentable over Fujita et al. (US 20230110995; "Fujita") in view of Sharon et al. (US 11488684).
Regarding independent claims 1 and 20, Fujita discloses a data storage device comprising:
a memory comprising a wordline, wherein the wordline comprises first and second sets of memory cells (para. 91; "According to some embodiments, both of the memory cells that are programmed to generate a joint data state may be physically coupled to a common word line (WL), but each memory cell of the pair is coupled to a separate bit line (BL)).
and one or more processors (Fig. 1 where it illustrates Processor 120), individually or in combination, configured to:
program a plurality of entangled pages of data in the first and second sets of memory cells, wherein read thresholds are shared between at least some of the plurality of entangled pages (para. 90; "a fractional number of bits-per-cell programming scheme may be applied in order to provide an improved balance between the objectives of increased storage density and efficient and steady performance.");
Fujita discloses a non-volatile memory that stores a fractional number of bits per cell using pairs of memory cells that generate joint data states, and further discloses that the same read level is applied to both cells of the pair. Fujita is silent with respect to calibrating the read thresholds of the entangled pages.
However, Sharon teaches and (means for) calibrate read thresholds of one of the plurality of entangled pages (col. 6, ln. 3-5; "A bit error rate (BER) estimation scan (BES) is another method to calibrate and optimize read thresholds.").
Fujita and Sharon are from the same field of endeavor as applicant' s invention directed to operations in fractional bit-per-cell memory. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the memory device of Fujita by applying the read-threshold calibration of Sharon. Both references are directed to improving the reliability and performance of multi-level NAND flash memory. Fujita's multi-threshold pages are subject to threshold voltage drift and would therefore benefit from the BES-based calibration methods taught by Sharon in order to minimize bit error rate and maintain data integrity.
Regarding claim 2, Fujita and Sharon combined disclose the limitations of claim 1.
As applied, Fujita further discloses data storage device of Claim 1, wherein read thresholds for the first and second sets of memory cells are identical (para. 97; "With respect to the fractional number of bits-per-cell programming approach, certain embodiments specify that the read level applied to both memory cells of the utilized pair be the same as a result of the construction, design, and architecture of the non-volatile memory."),
Fujita is silent with respect to the calibration method.
However, Sharon teaches and wherein the read thresholds of the one of the plurality of entangled pages are calibrated using a bit error rate (BER) estimation scan (BES) that applies a plurality of read operations around a single read threshold (col. 6, ln. 3-5; "A bit error rate (BER) estimation scan (BES) is another method to calibrate and optimize read thresholds. BES relies on optimizing the read threshold such that syndrome weight (SW), which is a proxy for the bit error rate, is minimized").
Regarding claims 4 and 12, Fujita and Sharon combined disclose the limitations of claims 1 and 10 respectively.
As applied, Fujita further discloses wherein the one or more processors, individually or in combination (Fig. 1, Processor 120), are further configured to perform
And also, as applied, Sharon further discloses a full scan of the plurality of read thresholds for a desired scanning resolution (col. 7, ln. 53-54; "As part of the BES operation, a grid of five or seven sense points is read allowing the emulation of all the 5*#TH or 7*#TH… different hypotheses for read threshold placement (note that the number of hypotheses is exponential with the number of thresholds)." It is noted that the exponential set of hypotheses constitutes a full scan of the plurality of read thresholds and the number of sense points (five or seven) sets the desired scanning resolution).
Regarding claims 5 and 13, Fujita and Sharon combined disclose the limitations of claims 1 and 10 respectively.
As applied, Fujita further discloses wherein the one or more processors, individually or in combination (Fig. 1, Processor 120),
And also, as applied, Sharon further discloses are further configured to perform an emulated scan (col. 9, ln. 44-45; "these embodiments can include the option to conduct emulations of reads instead of actually doing read.").
Regarding claim 9, Fujita and Sharon combined disclose the limitations of claim 1.
As applied, Fujita further discloses wherein the memory comprises a three-dimensional memory (Fig. 9. See also para 23; "a representative subsection of a monolithic three-dimensional NAND-type memory").
Regarding independent claim 10, Fujita discloses in a data storage device comprising
a memory, wherein a page of data is stored between first and second sets of fractional bits per cell (BPC) memory cells (para. 90; "According to various exemplary embodiments, a fractional number of bits-per-cell programming scheme may be applied in order to provide an improved balance between the objectives of increased storage density and efficient and steady performance."):
Fujita discloses a non-volatile memory that stores a fractional number of bits per cell using pairs of memory cells that generate joint data states but is silent with respect to a specific iterative process of fixing some read thresholds while scanning others, then reversing the process.
However, Sharon teaches fixing some read thresholds of the page of data (col. 8, ln. 9-14; "When operating the proposed decision-based read threshold calibration, the latency of the operation is set and very low. The bit error rate should only be calculated for 5*#TH or 7*#TH hypotheses. The minimum for each scanning comb will be selected as the optimal read threshold for that scanning comb, without any caveats or dependencies." It is noted that Sharon indicates that thresholds of a multi-threshold page can be treated independently.) while scanning other read thresholds of the page of data (col. 7, ln. 53-54; "As part of the BES operation, a grid of five or seven sense points is read allowing the emulation of all the 5*#TH or 7*#TH… different hypotheses for read threshold placement.);
performing a bit error rate estimation scan on the page of data to generate optimized scanned read thresholds (col. 6, ln. 3-5; "A bit error rate (BER) estimation scan (BES) is another method to calibrate and optimize read thresholds.");
fixing the optimized scanned read thresholds and scanning the previously-fixed read thresholds (Sharon does not explicitly disclose the reverse step. However, once the thresholds are understood to be independent (as noted above), the act of fixing the newly optimized thresholds and then optimizing the ones that were previously held fixed is a predictable continuation of the same multi-parameter optimization process. A person of ordinary skill in the art seeking a complete calibrated set would have found it obvious to reverse the process so that every threshold is optimized.);
calibrating the previously-fixed read thresholds (This step is the direct result of the revers scan of the element above and is therefore obvious for the same reasons);
and outputting a set of calibrated read thresholds for the page of data (Inherent in any successful multi-threshold calibration process. Sharon's BES produces optimized read thresholds that are thereafter used for reading.).
Fujita and Sharon are from the same field of endeavor as applicant' s invention directed to operations in fractional bit-per-cell memory. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the multi-threshold BES techniques of Sharon to the fractional BPC / joint-page memory of Fujita. Once Sharon's teaching that the thresholds of a multi-threshold page can be treated independently is applied to Fujita's joint pages, the sequential process of holding some thresholds fixed while optimizing others, and then reversing the process, is an ordinary and predictable multi-parameter optimization technique to obtain a complete set of calibrated thresholds with reduced computational complexity.
Regarding claim 11, Fujita and Sharon combined disclose the limitations of claim 10.
As applied, Fujita further discloses wherein the page of data comprises an entangled page of data (para. 92; "the pair of memory cells that form the basis of the joint data state map", "a 3.5 fractional bits memory cell has 12 possible data states and, when combined with a second memory cell with the identical storage capacity, forms 144 total joint data states and associated with each joint data state is a 7-bit binary number encoding.")
Regarding claim 17, Fujita and Sharon combined disclose the limitations of claim 10.
As applied, Sharon further discloses wherein the scanning is performed by the memory (col. 5, ln. 65-67; "valley search (VS) is an algorithm that can be used to optimize a read threshold by finding the minima on a cell voltage distribution (CVD) histogram between every two adjacent states. It is typically implemented inside the NAND die.". See also col. 9, ln. 58-59; "conducting a read threshold calibration process independently from the controller 102").
Regarding claim 18, Fujita and Sharon combined disclose the limitations of claim 10.
wherein the bit error rate estimation scan is performed by a controller in the data storage device (col. 1, ln. 60-64; "In one embodiment, a storage system is provided comprising a memory and a controller. The controller is configured to decode a codeword read from a wordline in the memory and cause read threshold calibration to be performed using data from the decoded codeword.", "using data from the decoded codeword instead of syndrome weight in a bit error rate estimate scan (BES).").
Regarding claim 19, Fujita and Sharon combined disclose the limitations of claim 10.
As applied, Sharon further discloses further comprising using the set of calibrated read thresholds to read the page of data (This step is the ordinary and necessary purpose of any read-threshold calibration. Once the thresholds have been optimized, they are applied to the subsequent reads of the page. Both Sharon and Fujita presuppose that the calibrated (or optimized) thresholds are thereafter used for reading.)
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Fujita et al. (US 20230110995; "Fujita") in view of Sharon et al. (US 11488684) and further in view of Pletka et al. (US 20230207023).
Regarding claim 3, Fujita and Sharon disclose the limitations of claim 1.
As applied, Fujita further discloses wherein read thresholds for the first and second sets of memory cells are different (para. 99; "apply a read voltage bias level that is not uniform across both memory cells within a pair of memory cells utilized in a fractional number of bits-per-cell programming approach. Rather, a first read voltage bias level may be applied to one memory cell within the memory cell pair, and a second read voltage bias level different from the first read voltage bias level may be applied to the second memory cell of the pair."),
Fujita and Sharon combined disclose the fractional-BPC memory in which the left and right side cells may use different read levels but are silent with respect to calibrating one page's thresholds by reusing calibrated values obtained from another page that shares a threshold.
However, Pletka teaches and wherein the read thresholds of the one of the plurality of entangled pages are calibrated based on read thresholds of other ones of the plurality of entangled pages that share a read threshold with the one of the plurality of entangled pages (Abstr. "Performing the read voltage threshold calibration includes calibrating read voltage thresholds based on only the particular physical page of the page group.". See also para. 46; "may apply the voltage thresholds determined for the affected page to all physical pages in the page group.". Although Pletka's page groups are formed on the basis of expected similarity of error characteristics (page type, word line, physical layer, etc.) rather than an explicit logical mapping "shared physical threshold" relationship of the kind illustrated in the instant application's entangled-page embodiment, under the broadest reasonable interpretation of claim 3 the distinction is not material. Claim 3 requires only that the system calibrate the thresholds of one page by using the calibrated values obtained from another page that is treated as sharing those thresholds – the functional result taught by Pletka.)
Fujita and Sharon combined, along with Pletka are from the same field of endeavor as applicant' s invention directed to operations in non-volatile memory. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply Pletka's page-group reuse technique to the multi-threshold joint pages of the memory device of Fujita as modified by Sharon. Doing so would address the problem of efficiently calibrating read thresholds across related pages. Reusing a calibrated threshold value obtained from one page for other pages that share (or are treated as sharing) that threshold is a known method of reducing calibration overhead, and yields the predictable result of lower latency and power while still obtaining usable thresholds for the subject page.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Shibata et al. (US 20190259458) – entangled data storage using pairs of memory cells across planes.
Papandreou et al. (US 20210065813) – read calibration in which some read voltages are calibrated independently while others receive a common offset.
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/James S. Wells/Examiner, Art Unit 2825
/Alfredo Bermudez Lozada/Primary Examiner, Art Unit 2825
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