This invention relates to methods of forming conductive contacts to source/drain regions of field effect transistors, and to methods of forming local interconnects.
Integrated circuitry includes a plurality of different type of electronic components or devices, some of which electrically connect with one another and others of which are electrically isolated from one another. By way of example only, exemplary devices include field effect transistors, capacitors and conductive lines. Field effect transistors are commonly composed of a pair of source/drain regions having a switchable channel region formed therebetween which is controlled by a conductive gate. Conductive electrical contact is typically made to one or both of the source/drain regions to connect the transistor with other integrated circuitry devices.
Conductive lines, for example transistor gate lines, can extend or run globally over large areas of a substrate comprising the integrated circuitry. Some conductive lines are much shorter and associated with very small portions of integrated circuitry, and are typically referred to as local interconnects. For example, and by way of example only, some local interconnects electrically connect source/drain regions of different field effect transistors. Further by way of example only, some local interconnects electrically connect a source/drain region of one transistor with a gate of another transistor. Further by way of example only, local interconnects are utilized to connect different conductive node regions of the integrated circuitry which do not necessarily constitute any portion of a field effect transistor.
While the invention was motivated in addressing the above identified issues, it is in no way so limited. The invention is only limited by the accompanying claims as literally worded, without interpretative or other limiting reference to the specification, and in accordance with the doctrine of equivalents.
The invention comprises methods of forming a conductive contact to a source/drain region of a field effect transistor, and methods of forming local interconnects. In one implementation, a method of forming a conductive contact to a source/drain region of a field effect transistor includes providing gate dielectric material intermediate a transistor gate and a channel region of a field effect transistor. At least some of the gate dielectric material extends to be received over at least one source/drain region of the field effect transistor. The gate dielectric material received over the one source/drain region is exposed to conditions effective to change it from being electrically insulative to being electrically conductive and in conductive contact with the one source/drain region.
In one implementation, a method of forming a local interconnect includes providing gate dielectric material intermediate a transistor gate and a channel region of a field effect transistor over a semiconductor substrate. At least some of the gate dielectric material extends to be received between first and second node regions of the semiconductor substrate. The gate dielectric material received between the first and second node regions is exposed to conditions effective to change it from being electrically insulative to being electrically conductive and a local interconnect is formed from the changed material which electrically connects the first and second node regions.
In one implementation, a method of forming a local interconnect includes providing capacitor dielectric material proximate a first capacitor electrode over a semiconductor substrate. At least some of the capacitor dielectric material extends to be received between first and second node regions of the semiconductor substrate. The capacitor dielectric material received between the first and second node regions is exposed to conditions effective to change it from being electrically insulative to being electrically conductive and a local interconnect is formed from the changed material which electrically connects the first and second node regions.
Other aspects and implementations are contemplated.
Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
By way of example only, exemplary preferred implementations of methods of forming a conductive contact to a source/drain region of a field effect transistor are initially described with reference to
Substrate fragment 10 comprises a field effect transistor 16 in fabrication. Such is depicted as comprising source/drain regions 18 and 20, and a channel region 22 therebetween in fabrication within semiconductive material 12. A transistor gate construction 24 is received operably proximate channel region 22, with a gate dielectric material 26 being provided over semiconductor substrate 12/14 intermediate transistor gate construction 24 and channel region 22. By way of example only, gate construction 24 is depicted as comprising a conductive transistor gate portion 28 comprised of two conductive layers, for example a metal or metal silicide layer 30 received over conductively doped polysilicon 32. Gate construction 24 is also depicted as comprising insulative sidewall spacers 34 and an insulative cap 36, for example comprised of silicon nitride. The depicted construction is exemplary only, and of course, other constructions are contemplated (whether existing or yet-to-be developed), and further by way of example only, the exemplary spacers and insulative cap (if used) might not be fabricated at this portion in the process. Further, at this point in the process, source/drain regions 18 and 20 (and channel 22) might or might not be effectively conductively doped with a conductively enhancing impurity, and further by way of example only, might constitute elevated source/drains and/or conductive metal and/or conductive metal compounds. In the depicted example, field effect transistor 16 is formed over a semiconductor substrate 12/14 and is oriented generally horizontally relative thereto, although of course other orientations are contemplated.
At least some of gate dielectric material 26 extends to be received over at least one of source/drain regions 18 and 20 of field effect transistor 16, with material 26 extending to be received over both such source/drain regions in the depicted example. Further in the exemplary preferred embodiment, all of the elevational thickness of gate dielectric material 26 extends to be received over the source/drain region or regions. An exemplary preferred thickness range for gate dielectric material 26 is from 5 Angstroms to 100 Angstroms. Preferably, extending gate dielectric material 26 is a high k dielectric material having a dielectric constant of at least 8. By way of example only, preferred gate dielectric materials 26 include metal oxides, for example any one or a combination of hafnium oxide, aluminum oxide, tantalum oxide, zirconium oxide and titanium oxide (and including silicates of hafnium, aluminum, tantalum, zirconium and titanium), to name a few. Other gate dielectric materials are, of course, also contemplated, and whether existing or yet-to-be developed. For purposes of the continuing discussion, gate dielectric material 26 can be considered as having an extending portion 31 received over source/drain region 20.
Referring to
Referring to
Referring to
By way of example only, the above exemplary preferred metal oxide dielectric materials might be transformed to conductive metal nitrides, conductive metal borides or conductive elemental metals of the metal oxides. For example, exposure of such materials to a nitrogen containing atmosphere (N2 and/or NH3), preferably including plasma species thereof at a preferred temperature range of from 500° C. to 900° C. and at a preferred pressure range of from 1 mTorr to atmospheric and above pressures, can be utilized to form conductive metal nitride (i.e., HfN, TaN, AlN and/or TiN) extending portions 31. If a hydrogen species, for example H2, were utilized in place of N2 or NH3, the exposure could be conducted for a time period effective to reduce the metal oxides all the way back to there elemental metals, including alloys thereof (i.e., Hf, Ta, Al and/or Ti). Exemplary exposure to B2H6 could be utilized to form conductive metal borides. Further by way of example only, the exposing could include forming the extending material to comprise an elemental metal followed by exposure to a reactive one of a nitride and/or boron containing material to form a conductive metal nitride and/or conductive metal boride.
Further by way of example where a silicide is desired to be formed, such might result from one or both of exposure to a silicon-comprising atmosphere, and/or from the reaction of metal of the extending gate dielectric material with silicon of the one source/drain region where such comprises silicon.
The exposing of gate dielectric material received over source/drain region 20 to change it from being electrically insulative to being electrically conductive also preferably, by way of example only, includes methods as described in our co-pending U.S. patent application Ser. No. 10/822,118, filed Apr. 8, 2004, which is now U.S. Patent Application Publication No. 2005/0227487, the application of which is herein fully incorporated by reference. Exemplary preferred methods are, by way of example only, described with reference to
Referring to
Referring to
The above exemplary preferred and described embodiment was with respect to fabrication of a field effect transistor which was oriented generally horizontally relative to the substrate. By way of example only,
The above-described exemplary preferred embodiments were with respect to methods of forming a conductive contact to a source/drain region through a contact opening in a dielectric layer received over the transistor gate and at least one source/drain region of the transistor. However, the invention also contemplates methods of forming a conductive contact to a source/drain region of a field effect transistor independent of such being conducted relative to a contact opening formed through a dielectric layer received over a transistor gate and a source/drain region. A preferred exemplary such method includes providing gate dielectric material intermediate a transistor gate and the channel region of a field effect transistor. At least some of the gate dielectric material extends to be received over at least one source/drain region of the field effect transistor. The gate dielectric material received over the one source/drain region is exposed to conditions effective to change it from being electrically insulative to be electrically conductive and in conductive contact with the one source/drain region. Preferred attributes are otherwise as described above independent of the provision of a dielectric layer 38 and a contact opening 40 therein.
The invention also contemplates methods of forming a local interconnect. First exemplary preferred embodiments of the same are described initially with reference to
Referring to
The above-described exemplary method of forming a local interconnect was where first and second node regions 66 and 68 comprise a source/drain region of one field effect transistor and a source/drain region of another field effect transistor. However, the invention also contemplates forming a local interconnect where one of the first and second node regions does not constitute any component of a field effect transistor, including any source/drain region. Of course, the invention contemplates forming a local interconnect where one of the first and second node regions is a source/drain region of one transistor, and the other of the first and second node regions is a gate of another transistor. Further, the invention also contemplates neither of first and second node regions 66 and 68 constituting any portion of a field effect transistor. Regardless and by way of example only, either of first and second node regions 66 and 68 might comprise any one or combination of the same or different conductively doped semiconductive material and/or at least one of an elemental metal (which includes alloys of elemental metals) and a conductive metal compound.
By way of example only, exemplary additional implementations of methods of forming a local interconnect are described with reference to
A capacitor 90 has been fabricated over dielectric layer 83. Such comprises a first capacitor electrode 92, a second capacitor electrode 94 and a capacitor dielectric material 95 received therebetween. Exemplary preferred materials for capacitor dielectric 95 include those described above for gate dielectric material 26. At least some of capacitor dielectric material 95 extends to be received between first and second node regions 86 and 88, respectively, of semiconductor substrate 80. In the depicted preferred embodiment, capacitor dielectric material 95 extends to be received over at least one of first and second node regions 86 and 88, with capacitor dielectric material 95 being received over both first and second node regions 86 and 88 in the exemplary embodiment.
Referring to
The exemplary
The above exemplary embodiments of
In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
This patent resulted from a divisional application of U.S. patent application Ser. No. 11/525,762, filed Sep. 21, 2006, entitled “Methods of Forming Conductive Contacts to Source/Drain Regions and Methods of Forming Local Interconnects”, naming Cem Basceri, Gurtej S. Sandhu and H. Montgomery Manning as inventors, which resulted from a divisional application of U.S. patent application Ser. No. 10/932,218, filed Sep. 1, 2004, entitled “Methods of Forming Conductive Contacts to Source/Drain Regions and Methods of Forming Local Interconnects”, naming Cem Basceri, Gurtej S. Sandhu and H. Montgomery Manning as inventors, the disclosures of which are incorporated by reference.
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Number | Date | Country | |
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20120070955 A1 | Mar 2012 | US |
Number | Date | Country | |
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Parent | 11525762 | Sep 2006 | US |
Child | 13302231 | US | |
Parent | 10932218 | Sep 2004 | US |
Child | 11525762 | US |