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 .
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) 1-9 and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over LEE (Pub. No.: US 2017/0077228) in view of Min (Pub. No.: US 2022/0069092).
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Re claim 1, LEE, FIGS. 3H-3I teaches a semiconductor structure comprising:
a first fin (left 120) and a second fin (right 120);
an epitaxial source/drain structure (130) disposed on the first fin and the second fin (left/right 120); and
a source/drain contact (MD of FIG. 3L) disposed on the epitaxial source/drain structure, wherein the source/drain contact and the epitaxial source/drain structure have a triangle interface (the hollow portions at the bottom) that spans a width of the source/drain contact along a gate lengthwise direction (direction along the length 142 of FIG. 4A) is below ([BofI], FIG. 6D [as shown above]) top surfaces of the first fin and the second fin (left/right 120).
LEE fails to teach wherein the source/drain contact and the epitaxial source/drain structure have a concave interface.
Min teaches wherein the source/drain contact (CT) and the epitaxial source/drain structure (SD, FIG. 2) have a concave interface.
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claim invention to include the above said teaching for the purpose of preventing short channel effect as taught by Min. [0004].
Moreover, after the combination of LEE and Lee would teach the concave interface is below top surfaces of the first fin and the second fin
Re claim 2, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 1, wherein the epitaxial source/drain structure includes:
a first epitaxial layer (left of 250 on the right) disposed on the first fin (left 210);
a second epitaxial layer (right of 250 on the right) disposed on the second fin (right 210); and
a third epitaxial layer (middle of 250 on the right) disposed on the first epitaxial layer and the second epitaxial layer, wherein the concave interface is between the third epitaxial layer and the source/drain contact (185).
Re claim 3, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 2, wherein the epitaxial source/drain structure further includes a fourth epitaxial layer (150 on the left) disposed on the third epitaxial layer.
Re claim 4, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 2, wherein the third epitaxial layer (middle of 250 on the right) includes a first sublayer disposed on the first fin and a second sublayer disposed on the second fin, the first sublayer merges with the second sublayer and forms a trough of the epitaxial source/drain structure (250 on the right), and the source/drain contact (185) fills the trough.
Re claim 5, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 1, wherein the source/drain contact includes a silicide layer (155/255, [0097]) and a conductive plug (185), wherein the silicide layer is between the conductive plug and the epitaxial source/drain structure (250/150) and Min teaches the silicide layer (of LEE) spans the width of the source/drain contact along the gate lengthwise direction (direction along the length 142 of FIG. 4A).
Re claim 6, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 1, wherein
an isolation structure (105a, FIG, 2, [0038]) is disposed between the first fin and the second fin (left/right of 250 on the right); and
LEE teaches a lowest point of the concave [BofI] interface below the top surfaces of the first fin and the second fin (left/right 120) is disposed over the isolation structure (105a of Min, FIG. 2, [0038]).
Re claim 7, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 5, wherein the silicide layer (155/255) is below the top surfaces of the first fin and the second fin (left/right 120 of LEE, FGIS. 3H-3I).
Re claim 8, in the combination, Min, FIG. 2 teaches the semiconductor structure of claim 5, wherein the epitaxial source/drain structure includes silicon germanium (210/250, [0033]), the silicide layer includes metal silicide (metal silicide, [0104]), and the conductive plug includes contact material (185).
Min differs from the invention by not showing the silicide layer includes titanium silicide, and the conductive plug includes cobalt.
However, it would have been obvious to one having ordinary skill in the art at the time of the invention was made to include the above said teaching since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416.
Re claim 9, LEE, FIG. 3H-3I teaches a device comprising:
a first fin (left 120) and a second fin (right 120) extending lengthwise along a first direction, wherein the first fin and the second fin each have a non-recessed portion and a recessed portion;
a gate extending lengthwise (140, ¶ [0023]) along a second direction that is different than the first direction, wherein the gate wraps the non-recessed portion of the first fin and the non-recessed portion of the second fin;
a merged epitaxial source/drain (130) on the recessed portion of the first fin and the recessed portion of the second fin; and
a source/drain contact (MD, FIG. 3L) on the merged epitaxial source/drain, wherein the source/drain contact and the merged epitaxial source/drain (130) have a V-shaped interface (at the bottom) therebetween and the source/drain contact extends below tops of the non-recessed portions of the first fin and the second fin (top most surface of 120).
LEE fails to teach an isolation structure between the recessed portion of the first fin and the recessed portion of the second fin along the second direction; a merged epitaxial source/drain on the recessed portion of the first fins and on the recessed portion of the second fin, and over the isolation structure.
Min teaches an isolation structure (105a, FIG. 2m [0038]) between the recessed portion of the first fin and the recessed portion of the second fin (left/right of 250 on the right) along the second direction; a merged epitaxial source/drain on the recessed portion of the first fins and on the recessed portion of the second fin, and over the isolation structure 105a).
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claim invention to include the above said teaching for the purpose of preventing short channel effect as taught by Min. [0004].
Moreover, after the combination of LEE and Min would teach a source/drain contact on the merged epitaxial source/drain, wherein the source/drain contact and the merged epitaxial source/drain have a V-shaped interface therebetween that is over the isolation structure.
Re claim 13, in the combination, LEE, FIGS. 3H-3I teaches the device of claim 9, wherein a tip of the V-shaped interface (at the bottom of interface between MD and 130) is between the first fin and the second fin (120) along the second direction.
Claim(s) 10-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over LEE in view of Lee (Pub. No.: US 2023/0128547).
Re claim 10, LEE teaches all the limitation of claim 9.
LEE fails to teach the limitation of claim 10.
Lee teaches wherein the source/drain contact includes a silicide layer (160S, FIG. 3, [0040]) disposed below tops of the non-recessed portions of the first fin and the second fin (the top flat portion of SD between 160S).
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claim invention to include the above said teaching for the purpose of enhancing more reliable electrical connection may be obtained and contact resistance may be reduced as taught by Lee, [0042].
Re claim 11, in the combination, Lee, FIG. 3 teaches the device of claim 10, wherein an angle between a first top surface of the silicide layer and a second top surface of the silicide layer is about 80° to about 140° (160S).
Re claim 12, LEE teaches wherein the source/drain contact (MD of FIG. 3L) extends to a depth below the tops of the non-recessed portions of the first fin and the second fin (left/right 120).
LEE differs from the claim invention by not disclosing wherein the depth is about 15 nm to about 25 nm.
However, Applicant has not disclosed that the ranges are for particular unobvious purpose, produce an unexpected result, or are otherwise critical. Therefore, it would have been obvious to one having ordinary skill in the art at the time the invention was made to include the above said teaching, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%.); see also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Hoeschele, 406 F.2d 1403, 160 USPQ 809 (CCPA 1969) (Claimed elastomeric polyurethanes which fell within the broad scope of the references were held to be unpatentable thereover because, among other reasons, there was no evidence of the criticality of the claimed ranges of molecular weight or molar proportions.). For more recent cases applying this principle, see Merck & Co. Inc. v. Biocraft Laboratories Inc., 874 F.2d 804, 10 USPQ2d 1843 (Fed. Cir.), cert. denied, 493 U.S. 975 (1989); In re Kulling, 897 F.2d 1147, 14 USPQ2d 1056 (Fed. Cir. 1990); and In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997).
Claim(s) 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over LEE in view of Wu (Patent No.: US 10930564).
Re claim 14, LEE, FIG. 3H-3I teaches wherein the source/drain contact is a first source/drain contact, the device further comprising:
a third fin (middle 120) extending lengthwise along the first direction, wherein the third fin has a non-recessed portion and a recessed portion;
the gate wraps (140) the non-recessed portion of the third fin;
an epitaxial source/drain (130) on the recessed portion of the third fin; and
a source/drain contact (MD, FIG. 3L) on the epitaxial source/drain, wherein the source/drain contact and the epitaxial source/drain have a V-shaped interface therebetween and the second source/drain contact extends below a top of the non-recessed portion of the third fin (middle 120).
Furthermore, the following limitation “the epitaxial source/drain have a U-shaped interface” had a little patentable weight because it has been held that where the only difference between the prior art and the claims was a recitation of relative size or shape of the claimed device, and a device having the claimed relative size or shape would not perform differently than the prior art device, the claimed device was not patentably distinct from the prior art device (MPEP §2144.04) and it would have been obvious that a mere change in shape of a component is generally recognized as being within the level of ordinary skill in the art.
LEE fails to teach a second source/drain contact.
Wu teaches a second source/drain contact (right 188, FIG. 1C, col. 7, lines 10-15).
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claim invention to include the above said teaching for the purpose of enlarging S/D contact landing area and reducing S/D contact resistance as taught by Wu, BACKGROUND.
Re claim 15, in the combination, Wu, FIG. 1C teaches the device of claim 14, wherein:
the first source/drain contact (left 188) has a first depth below the tops of the non-recessed portions of the first fin and the second fin (left 162);
the second source/drain contact (right 188) has a second depth below the top of the non-recessed portion of the third fin (right 162); and
the first depth (the depth that touch 114a) is greater than a second depth (the depth that touch 114b).
Allowable Subject Matter
Claims 21-25 are allowed.
The following is an examiner’s statement of reasons for allowance:
In the claim 21 that is written, the prior arts fail to show or fairly suggest the process steps of: “a third epitaxial material portion having a second dopant concentration greater than the first dopant concentration, wherein the third epitaxial material portion is disposed on the first epitaxial material portion, the third epitaxial material portion is disposed on the second epitaxial material portion, and the third epitaxial material portion is disposed over the first fin spacers, the second fin spacers, and the isolation structure” in context with the other limitation as stated in claim 21.
Response to Arguments
Applicant's arguments with respect to claims 1-15 on the remarks filed on 01/14/2026 have been considered but are moot in view of the new ground(s) of rejection.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TONY TRAN whose telephone number is (571)270-1749. The examiner can normally be reached Monday-Friday, 8AM-5PM, EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Britt Hanley can be reached at 571-270-3042. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TONY TRAN/Primary Examiner, Art Unit 2893