Texas Instruments Corporation

Other

Shin-Puu Jeng

Bruce E Gnade

Douglas M Smith

William C Ackerman

Gregory P Johnston

Robert H Havemann

Qi-Zhong Hong

Richard A Stoltz

Wei-Yung Hsu

Teresa A Ramos

Alok Maskara

Chih-Chen Cho

Kelly Jay Taylor

Amitava Chatterjee

Dennis I Robbins

Johnson J Lin

Mi-Chang Chang

This invention has enabled a new, simple thin film nanoporous dielectric fabrication method. In general, this invention uses glycerol, or another low volatility compound, as a solvent. This new method allows thin film aerogels/low density xerogels to be made without supercritical drying, freeze drying, or a surface modification step before drying. Thus, this invention allows production of nanoporous dielectrics at room temperature and atmospheric pressure, without a separate surface modification step. Although this new method allows fabrication of aerogels without substantial pore collapse during drying, there may be some permanent shrinkage during aging and/or drying. This invention allows controlled porosity thin film nanoporous aerogels to be deposited, gelled, aged, and dried without atmospheric controls. In another aspect, this invention allows controlled porosity thin film nanoporous aerogels to be deposited, gelled, rapidly aged at an elevated temperature, and dried with only passive atmospheric controls, such as limiting the volume of the aging chamber.

Low volatility solvent-based method for forming thin film nanoporous aerogels on semiconductor substrates

This invention pertains generally to precursors and deposition methods suited to aerogel thin film fabrication. An aerogel precursor sol which contains an oligomerized metal alkoxide (such as TEOS), a high vapor pressure solvent (such as ethanol) and a low vapor pressure solvent (such as water and 1-butanol) is disclosed. By a method according to the present invention, such a precursor sol is applied as a thin film to a semiconductor wafer, and the high vapor pressure solvent is allowed to evaporate while evaporation of the low vapor pressure solvent is limited, preferably by controlling the atmosphere adjacent to the wafer. The reduced sol is then allowed to gel at a concentration determined by the ratio of metal alkoxide to low vapor pressure solvent. One advantage of the present invention is that it provides a stable, spinnable sol for setting film thickness and providing good planarity and gap fill for patterned wafers. In addition, however, the reduced sol may be gelled rapidly from a known sol concentration keyed to the desired final density of the aerogel thin film and largely independent of film thickness and spin conditions.

Aerogel thin film formation from multi-solvent systems

This pertains generally to precursors and deposition methods suited to aerogel thin film fabrication of nanoporous dielectrics. An aerogel precursor sol is disclosed. This aerogel precursor sol contains a metal alkoxide (such as TEOS) and a solvent, but no gelation catalyst. By a method according to the present invention, such a precursor sol is applied as a nongelling thin film,to a semiconductor substrate,This substrate may contain patterned conductors,gaps,or other structures. An independent gelation catalyst (preferably, vapor phase ammonia) is added to promote rapid gelation of the thin film sol,at the desired time. One advantage is that it allows substantially independent control of gelation and pore fluid evaporation. This independent catalyst introduction allows additional processing steps to be performed between sol deposition and the onset of substantial gelation. One potential step is to evaporate a portion of the pore fluid solvent. Additional advantages of independent catalyst introduction are that it reduces the need for process steps requiring critical timing and provides a large increase in the pot life of the precursor sol.

Nanoporous dielectric thin film formation using a post-deposition catalyst

This invention pertains generally to precursors and deposition methods suited to aerogel thin film fabrication. An aerogel precursor sol which contains an oligomerized metal alkoxide (such as TEOS), a high vapor pressure solvent (such as ethanol) and a low vapor pressure solvent (such as water and 1-butanol) is disclosed. By a method according to the present invention, such a precursor sol is applied as a thin film to a semiconductor wafer, and the high vapor pressure solvent is allowed to evaporate while evaporation of the low vapor pressure solvent is limited, preferably by controlling the atmosphere adjacent to the wafer. The reduced sol is then allowed to gel at a concentration determined by the ratio of metal.alkoxide to low vapor pressure solvent. One advantage of the present invention is that it provides a stable, spinnable sol for setting film thickness and providing good planarity and gap fill for patterned wafers. In addition, however, the reduced sol may be gelled rapidly from a known sol concentration keyed to the desired final density of the aerogel thin film and largely independent of film thickness and spin conditions.

An improved method is provided for integrating HSQ into integrated circuit structures and processes, especially those requiring multiple levels of interconnect lines. In a preferred embodiment, interconnect lines 14 are first patterned and etched on a substrate 10. A low-k material such as hydrogen silsesquioxane (HSQ) 18 is spun across the surface of the wafer to fill areas between interconnect lines. A capping layer such as SiO.sub.2 20 is applied to on top of the low-k material. The HSQ is then heated to cure. A thick SiO.sub.2 planarization layer 22 may then be applied and planarized. In other embodiments, the HSQ and SiO.sub.2 process steps can be repeated for multiple layers of HSQ.

Hydrogen silsesquioxane thin films for low capacitance structures in

This pertains generally to precursors and deposition methods suited to aerogel thin film fabrication of nanoporous dielectrics. A method of forming a nanoporous dielectric on a semiconductor substrate is disclosed. By a method according to the present invention, a precursor sol is applied as a nongelling thin film 14 to a semiconductor substrate 10. This substrate may contain patterned conductors 12, gaps 13, and/or other structures. A portion of the solvent is evaporated from the thin film 14 to produce a reduced thickness film 18. Film 18 is gelled and may be aged. A surface modification agent is introduced to the reaction atmosphere in a vaporish form, e.g., a vapor, mist, aerosol, or similar form. The surface modifier can then diffuse into, condense onto, and/or settle onto the wet gel and then diffuse throughout the thin film. This vaporish introduction of the surface modification agent ensures that there are no strong fluid flows across the wafer that might damage the wet gel. It can also be compatible with standard processing equipment and can potentially be used with other reaction atmosphere controls that reduce premature drying of the gel.

Nanoporous dielectric thin film surface modification

In accordance with the present invention, an improved method and structure is provided for integrating polymer and other low dielectric constant materials, which may have undesirable properties, into integrated circuit structures and processes, especially those requiring multiple levels of interconnect lines. Since the bond is typically weak between low-k materials such as polymers 18 and traditional dielectrics such as SiO.sub.2 22, the weak bonding may cause delamination or other problems during subsequent processing. The present invention increases yield and simplifies processing subsequent to application of the low-k material by providing an adhesion/protective layer 20 between the low-k material 18 and the intermetal dielectric 22. A preferred embodiment is a spun-on layer 20 of HSQ cured on a hotplate prior to application of the SiO.sub.2 intermetal dielectric.

Low capacitance interconnect structures in integrated circuits having an

A method is provided for forming sidewall diffusion barriers from a dielectric material. A trench or via is formed in a semiconductor device. A layer of dielectric material is deposited over the surfaces of the semiconductor device. The deposited layer of dielectric material is removed from all surfaces except the sidewall of the trench or via, thereby forming the dielectric diffusion barriers on the sidewall. Because dielectric materials have an amorphous structure which does not readily permit diffusion, impurities do not need to be added to the dielectric diffusion barriers. Furthermore, dielectric diffusion barriers produce a smaller RC time delay relative to metallic diffusion barriers having a comparable thickness.

Method of forming diffusion barriers encapsulating copper

Methods are provided for the construction of metal-to-metal connections between non-adjacent layers in a structure, such as a semiconductor device. A first metal conductor layer is provided along a substrate. An anti-reflection cap is provided in overlying relation with said first conductor layer. At least a portion of the dielectric layer and the anti-reflection cap is removed to define a passage which extends from an upper surface of the dielectric layer to the first metal conductor. The passage is substantially filled with a fill metal, and a second metal conductor layer is applied over at least a portion of the dielectric layer and the substantially filled passage to electrically connect the first and second metal conductors. A diffusion liner can optionally be applied to the passage prior to application of the fill metal. The passage fill metal and second conductor layer can be integrally formed, and the fill metal and at least one of the conductor layers are formed from the same matrix metal.

Method for producing barrier-less plug structures

Low volatility solvent-based method for forming thin film nanoporous

A method for forming air gaps 22 between metal leads 16 of a semiconductor device and semiconductor device for same. A metal layer is deposited on a substrate 12. The metal layer is etched to form metal leads 16. A disposable solid layer 18 is deposited between the metal leads 16. A porous dielectric layer 20 is deposited on the disposable solid layer 18 and the tops of the leads 16, and the disposable solid layer 18 is removed through the porous dielectric layer 20, to form air gaps 22 between the metal leads 16 beneath the porous dielectric layer 20. The air gaps have a low-dielectric constant and result in reduced sidewall capacitance of the metal leads.

Multilevel interconnect structure with air gaps formed between metal

A TiSi.sub.2 /TiN clad LI strap process and structure are disclosed which combine the advantages of both TiSi.sub.2 and TiN LI processes. According to the invention, the retention of a thin TiN layer between the local interconnect and contacts provides a diffusion barrier against counterdoping and relaxes the thermal budget for subsequent processing.

TiSi.sub.2 /TiN clad interconnect technology

A low capacitance interconnect structure and process is provided for integrating low-k decomposed polymers into integrated circuit structures and processes, especially those requiring multiple levels of interconnect lines, for reduced capacitance over prior art structures. Embodiments of the present invention use polymers which typically decompose into gases with lower dielectric coefficients than the original polymer to provide a lower dielectric constant material between conductive interconnects on an integrated circuit. The materials are decomposed after being sealed in with a cap layer to prevent contamination of the gas filled void left after decomposition. The present invention also combines the advantages of SiO.sub.2 with low dielectric decomposed polymers by placing the low decomposed material only between tightly spaced lines. The low-k polymer material can be applied by spin-on techniques or by vapor deposition.

Growing community of inventors

Plano, TX, United States of America

Shin-Puu Jeng